XL2

OPERATING MANUALHANDHELD AUDIO AND
ACOUSTIC ANALYZER

Contact NTi Audio at
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Firmware V4.84
Version 4.84.00 / Dec 22
All information subject to change without notice.
©
All rights reserved.
®
Minirator is a registered trademark of NTi Audio.
™
XL2, XL2-TA, EXEL, M2230, M2340, M2211, M2215, M4261, MA220, MA230,
M2230-WP, M2340-WP, M4261-WP, WP30 and WP61 are trademarks of NTi Audio.

Made in
Sw i t ze r l a n d

Table of Contents

Table of Contents
1. Introduction......................................................................5
2. Overview...........................................................................7
Operation........................................................................9
The Screen Display....................................................... 11
3. Getting Started..............................................................14
Power Supply ............................................................... 14
Attaching the Hand Strap.............................................. 17
Unfolding the Stand...................................................... 18
Connecting the XL2 ..................................................... 18
Switching the XL2 On and Off......................................20
Select Measurement Function......................................20
Calibration prior Measurement.....................................21
4. Sound Level Meter.........................................................22
Overview......................................................................26
Sound Level Meter - Getting Started............................34
RTA Measurement - Getting Started............................39
Reporting......................................................................43
Wav-File Recording.......................................................46
Events (optional)...........................................................49
Limits............................................................................56
Correction Value KSET..................................................58
Locked Run Mode.........................................................62

5. Acoustic Analyzer...........................................................64
FFT Analysis + Tolerance...............................................64
Reverberation Time....................................................... 74
Polarity..........................................................................86
Delay Time....................................................................90
1/12 Octave + Tolerance (optional)................................96
Noise Curves (optional)............................................... 108
Speech Intelligibility STIPA (optional).......................... 118
6. Audio Analyzer.............................................................135
RMS / THD+N............................................................. 135
Oscilloscope............................................................... 138
7. Vibration Meter.............................................................139
VibMeter / Spectrum.................................................. 139
FFT Analysis + Tolerance............................................. 146
Oscilloscope............................................................... 150
1/12 Octave + Tolerance (optional).............................. 151
8. Calibration....................................................................156
9. Profiles..........................................................................163
10. Spectral Limits Option (Capture + Tolerances)........ 170
11. System Settings......................................................... 183
Settings....................................................................... 183
3

Table of Contents
Vibration...................................................................... 186
Scheduler.................................................................... 187
Options....................................................................... 189
Information................................................................. 190

Warranty Conditions...................................................272
Service and Repairs....................................................273
Calibration Certificate..................................................273
Declaration of Conformity...........................................275

12. Data Management..................................................... 191
Record Voice Notes..................................................... 197
Recall Measurements.................................................203
Append Measurements .............................................205

23. Technical Data XL2..................................................... 276

13. XL2 Projector PRO Software..................................... 210

Appendix..........................................................................299
Appendix 1: Standard - Optional Features..................299
Appendix 2: Factory Default Profiles..........................303
Appendix 3: Description Sound Levels.......................308
Appendix 4: Common Sound Levels........................... 313
Appendix 5: Vibration Meter Functions....................... 319

14. Data Explorer (optional)............................................212
15. Building Acoustics (optional)....................................214
16. Room Acoustics (optional)........................................216
17. Sound Power (optional)............................................. 218
18. Unattended Noise Monitoring......................................220
19. Time Synchronization...............................................226
20. Remote Measurement...............................................230
21. Microphones ..............................................................232
22. Further Information...................................................247
My NTi Audio..............................................................247
Firmware Update........................................................250
Options.......................................................................251
Accessories................................................................261
4

24. Technical Data Microphones.....................................288
25. Technical Data PreAmplifier.......................................298

Details IEC 61672 & IEC 61260........................................322
General Information....................................................324
Class 1 Sound Calibrator.............................................327
Accessory...................................................................327
Level Linearity.............................................................328
Level Linearity of Octaveband-Spectrum....................330
Level Linearity of Third-Octaveband-Spectrum...........331
Self-generated Noise with Microphone......................332
Frequency Response Corrections...............................334
Frequency Weighting..................................................338
Directional Response (dB)..........................................339
Information for Calibration.............................................344

Introduction

1.

Introduction

Thank you for purchasing the XL2 Audio and Acoustic Analyzer.
The XL2 Analyzer forms the unique combination of a state-ofthe-art Sound Level Meter, a comprehensive Acoustic Analyzer
as well as a powerful Audio Analyzer. The wide range of functionalities is tailored for:• Evacuation Systems- Speech Intelligibility• Electroacoustic Installations- Installed Sound- AV Installations- Cinemas• Noise Measurement- Unattended Noise Monitoring- Environmental Noise- Occupational Health- Vehicle Noise- Sound Power• Live Sound- Sound Level Monitoring- Front of House- PA Rental• Broadcast• Room & Building Acoustics- Room Acoustics- Building Acoustics- Reverberation Time- Noise Curves• Industrial Quality Control• Condition Monitoring

How to Read this Manual
The XL2 push buttons are displayed as icons,,,,, , , , . A detailed description of the push buttons islisted in the chapter Overview - Operation.
Menu items displayed on the XL2 page screens are shown inthis user manual by a bold font, e.g., SLMeter, Parameter, ...

5

Introduction

Product Configurations
The following items are included with the respective model:

6

XL2
without
Microphone• XL2 Analyzer• USB Flash Drive with test signals• USB cable• Li-Po battery• Hand strap• Operating manual

XL2 +
M2230

• XL2 Analyzer• M2230 Measurement Microphoneconsisting of- Microphone PreAmplifier MA220- Microphone Capsule MC230 or MC230A• 50 mm Windscreen• Microphone-holder MH01
with Adapter 5/8“ - 3/8“• Individual Frequency Response Chart• USB Flash Drive with test signals• Li-Po battery• USB cable• Hand strap• Operating manual

XL2 +
M2211

• XL2 Analyzer• M2211 Measurement Microphoneconsisting of- Microphone PreAmplifier MA220- Microphone Capsule 7052
• 33 mm Windscreen• Microphone-holder
with Adapter 5/8“ - 3/8“• USB Flash Drive with test signals• Li-Po battery• USB cable• Hand strap• Operating manual

XL2 +
M4261

• XL2 Analyzer• M4261 Measurement Microphone• 33 mm Windscreen• Microphone-holder
with Adapter 5/8“ - 3/8“• USB Flash Drive with test signals• Li-Po battery• USB cable• Hand strap• Operating manualOverview

2.

Overview

11 Tripod Mount

XL2 interfaces:

10 Speaker

6 Digital I/O

1
XLR Input

9
Headphone
Output5 USB Connector

23
Voice Note Input

RCA Input

4 DC Power Socket

8 TOSLink Output
7 SD Card
7

Overview

XLR Signal Input
Either a balanced audio signal, an NTi Audio measurement microphone or the microphone pre-amplifier MA220
plug directly into the XLR input. The Automated Sensor Detection (ASD) technology reads the electronic
data sheet of any connected NTi Audio device after the
48 V microphone phantom power is activated.

7

SD Card
For storing data, screenshots, voice notes, wav-files - required to power on and run the instrument.

8

TOSLink Output
24 bit linear PCM audio signal output. For future use; notactive at this time.

2

RCA Input
Unbalanced audio signal input.

93

Voice Note Input
Internal microphone for recording voice notes and measuring polarity and delay time. For polarity measurements, anexternal microphone may also be used.

4

DC Power Socket
Socket for mains power adapter. Further details in the chapter Power Supply in this manual.

Headphone Output
The XLR/RCA input signals are routed to the headphone
connector (3.5 mm Minijack; mono monitor wired to bothchannels of stereo jack). Connecting headphones mutes theinternal speaker. To connect the headphone output directly to a line input, a load impedance < 8 kOhm is requiredfor proper operation. This can be achieved by inserting a
1 kOhm resistance between tip and ground of the output
jack.

1

5

USB Connector
Mini-B USB connection, for accessing the SD Card.

6

Digital I/O
Programmable digital inputs/outputs.

8

10 Speaker

The XLR/RCA input signals are routed to the speaker. Press
the speaker button
to toggle the speaker on/off. Press
and hold the speaker button to access the volume control.
Set the speaker level with the rotary wheel .
11

Tripod Mount
Mechanical mount for attaching the XL2 to a tripod or microphone stand.

OverviewOperation2

98

 The speaker is activated and the speaker or headphone6

7

Volume of Speaker and Headphone Output• Press the button
briefly to enable or disable the speaker.

icon appears in the upper menu bar.
• Press and hold the speaker button.

 A pop-up window for volume is displayed.
1

5

2

1

3

4

Page Control
Switches among various screens depending on the menufunction selected.
9Overview• Hold the speaker button
down and adjust the levelof the speaker and headphone outputs with the rotary
wheel . Digital gain control prevents gain increases beyond a level that will cause signal clipping. The maximum
gain setting depends on the connected input signal.
• The headphone output provides a linear output signal using the SLMeter function over a measurement range of
57 dB. The minimum Z-weighted sound pressure level atreference sensitivity is:- M2230, M2340: 58 dB- M2211: 64 dB- M4261: 66 dB
3

4

10

Power & Backlight
The power button switches the instrument on. The XL2 isimmediately ready for operation. Holding down the power
buttonfor one second switches the XL2 off. Additionally,a brief press of the power button
toggles the backlightduring operation.
Limit• SLMeter: The limit button lights up green, yellow or red
according to the settings in the Limit page. Press thelimit button
to access the Limit page. For more details
visit the chapter Sound Level Meter: Limits.

• FFT + Tol: The limit button lights up green for results
within tolerance and red for out-of-tolerance results.
• Polarity: The limit button lights up green at positive polarity and red at negative polarity.
• 1/12 Oct + Tol: The limit button lights up green for results
within tolerance and red for out of tolerance results.
5

Pause
Pauses the current measurement. Press the pause buttonor the start/stop button
to continue the measurement. The data logging is continued in the function SLMeter/RTA during the pause period and listed in the log file.

6

Start/Stop
Starts and stops a measurement.

7

Enter
Confirms a selection.

8

Rotary Wheel
Selects the required measurement function or the individual measurement parameter.

9

ESC
Terminates an entry, returns to the top menu level or closes
an open window.

Overview

The Screen Display
The XL2 displays the actual sound levels also in case of nomeasurement has been started. Any displayed averaged levelrefers to the previous measurement period. The XL2 shows
four lines in case of no previous measurement period is applicable.

Display Contrast Setting• Hold down escapeand turn the rotary wheel
desired contrast is reached.

2

3

4

5

6

7

8

9

until the1

Updating of display• Numeric values
Updated every 500ms independent of the measurement
function. The maximum time span between the end of
the measurement period and the first test result display is
500ms.
• Graphs and spectra
Updated every 50ms
The display is updated continuously during measurement.

11

Overview

1

Measurement Results
Individual level measurement results.

2

Main Menu

12

SLMeter/RTA

SPL & RTA Measurement

FFT + Tol

FFT Analysis with optional ToleranceManagement

RT60

Reverberation TimePolarity

Polarity

Delay Time

Delay Time

RMS/THD+N

RMS Level and Distortion

Oscilloscope

Scope

1/12 Oct + Tol

Spectral Analysis with Tolerance Management (optional)

Noise Curves

Noise Curves

STIPA

Speech Intelligibility (optional)

Cinema Meter

Calibration and verification of cinema
loudspeaker systems (optional)

Calibrate

Calibration Menu for microphone

Profile ...

Store and load measurement profiles

SystemSystem Settings

3

Page Selector
Toggles between available measurement and result pages
within the same function menu. Alternatively use the page
button.

4

Input Selector
Select XLR or RCA input connectors as the source.

5

Memory Menu
The memory menu is used for data storage management.
One of the following symbols flashes before or after starting the measurement:
9-8-7

Time in seconds until instrument is settled andmeasurement will start.

RUN

Indicates the ongoing measurement.

LOG

Indicates the ongoing measurement with data
logging.

AUD

Indicates the ongoing measurement with data
logging and audio recording.

Evt

Indicates an ongoing triggered-event recording.

OverviewAfter a completed measurement, the memory symbol
indicates a non-saved measurement report. Your measurement needs to be stored manually. For more details visit
the chapter Data Management.
6

7

Speaker/Headphone
Indication of enabled rear speaker or headphone output.
Phantom Power Supply
48V

The XL2 provides 48 V Phantom power supply
to the connection microphone or sensor.

ASD

An NTi Audio measurement microphone with
automated sensor detection ASD is connected. The XL2 reads the electronic data sheet ofthe microphone and switches the 48 V Phantom power automatically on

48V

9Battery Symbol
The battery symbol indicates the battery status as follows:
Using rechargeable Li-Po battery:
Level indication 100% (U > 4.0 Volt).
(Battery charges when mains adaptor connected)
Level indication:
75%: U = 3.9 - 4.0 Volt
50%: U = 3.8 - 3.9 Volt
25%: U = 3.7 - 3.8 Volt
Level indication 0% (U < 3.7 Volt). The battery isalmost empty and must be recharged.
The battery is being recharged by the mains
power adapter.
The XL2 is connected via USB to a computer.
The battery charge level decreases slowly during XL2 usage.

Phantom power is switched off.
Using standard AA batteries:

8

Real-Time Clock
The real-time clock is set in the System menu.

No level indication as long as U > 4.5 Volt.
Level indication 0% (U < 4.5 Volt). The batteries
are almost empty and should be replaced.
Using mains or supply:
No indication of battery status.
13

Getting Started

3. Getting Started
Power Supply
The XL2 offers flexible power management options and can be
operated either by• Replaceable, rechargeable lithium-polymer (Li-Po) battery(included with the XL2 Analyzer)• 4x AA-batteries• Mains Power Adapter
The new battery is charged to approximately 50% and should
be fully charged before use with:Battery Charger(optional)

Charging Time: approx. 3 hours
NTi Audio #: 600 000 332

Mains Power
Adapter(optional)

Charging Time: approx. 6 hours
Leave the battery inside and switch off
the XL2. Running the XL2 during
charging prolongs the charging time.
NTi Audio #: 600 000 333

USB Power
from PC

14

Charging Time: approx. 6 hours
Switch off the XL2
for charging. The
charging power is equal or less than the
power consumption.

Operation using Mains Power Supply
You can also operate the XL2 with the optional NTi Audio Mains
Power Adapter. During such operation it is recommended toleave the batteries inside the instrument.

Mains Power Adapter• Electrically-isolated, linear DC power supply• A decreased THD+N performance will occur with unbalanced input signals when using switching-type power supplies (approx.
3 dB).
• Non-NTi Audio power supplies may have further negative effects on measurements.
• Damage caused by using an inappropriate external DC supply is not covered by warranty.

DC Power supply specifications• Voltage: 7.5 - 20.0 Volt
• Power: minimum 6 Watt
• Connector type: 2.1 x 5.5 x 9.5 mm• Polarity:.

Getting Started

Rechargeable Li-Po Battery• Open the battery cover at the rear of the instrument.
• Insert the rechargeable battery with the contacts edge first.
• Close the battery cover.

Switch off the XL2
for faster recharging by
mains power adapter or USB connection.

3.

2.

Caution• Switch the XL2 off prior opening the battery
cover in order to prevent any electronic discharges.
• Avoid short-circuits.
• Operate and charge the battery between 0°C
and 45°C (32°F - 113°F).
• Do not heat the battery above 60°C.
• Do not place the battery in or near fire.
• Do not solder directly on to the battery.
• Do not disassemble the battery.
• Do not insert the battery in reverse polarity.
• Remove the battery for applications with aconnected mains power adapter over multiple weeks.

1.

15Getting Started

AA-Batteries
Alternatively, the XL2 can be powered by AA type batteries• Open the battery cover.
• Insert 4 fully-charged AA batteries, observing correct polarityof the +/- indications in the battery compartment.

2.

 The polarity alternates with successive batteries.
• Close the battery cover.

• Switch the XL2 off prior opening the battery
cover in order to prevent any electronic discharges.
• Use only similar batteries from the same
manufacturer.
• Replace discharged batteries with new ones.
• Do not mix used and new batteries.
• During operation, the battery temperature
may increase noticeably. This is not a defect.
• Remove all batteries if the XL2 is not to be
used over a long period of time.

16

1.

Getting Started

Attaching the Hand Strap
To avoid accidentally dropping the XL2, a hand strap is suppliedwith the instrument.
• Pull the loop of the hand strap through the opening.
• Pull the other end of the hand strap through the loop.
• Pull the hand strap tight.

1.

2.

3.

17

Getting Started

Unfolding the Stand

Connecting the XL2

A convenient table stand is attached to the rear of the instrument.

Acoustic Measurements
Connect an NTi Audio measurement microphone to the XLR
input connector of the XL2.

• Unfold the stand and rest the XL2 on a flat surface.

18

Getting Started

Audio Measurements: XLR Connection• Connect the source to the XL2 with an XLR cable.
• Select the XLR input in the menu.

Audio Measurements: RCA Connection• Connect the source to the XL2 with an RCA (cinch) cable.
• Select the RCA input in the menu.

19

Getting Started

Switching the XL2 On and Off

Select Measurement Function

Switching On the XL2• Navigate with the rotary wheel
to the main menu bar.
• Confirm with enter
to select the measurement function.

Press power

to switch on the XL2.

 There is a brief sound of relays and the display illuminates.

 The main menu window opens

Switching Off the XL2
Press power
the XL2.

and hold it down for one second to switch off

Main menu with enabled options• Scroll up/down with the rotary wheel
quired function and confirm with enter The measurement function is selected.
20

to select the re.

Getting Started

Setting the Parameters with the Rotary Wheel• Turn the rotary wheel
to navigate within the display
screen.

 The selected parameter is highlighted with a black back-Calibration prior Measurement
We recommend the daily calibration of the XL2 Analyzer with
the Sound Calibrator. This ensures accurate measurement results.

ground.
For more details see chapter Calibration.
• Confirm with enter.

 The parameter display flashes and/or available parametersor settings are shown.
• Turn the rotary wheel
to set the parameter or toggle withenter
through the settings.
• Confirm with enter .

 Now the parameter is set.

21

Sound Level Meter

4.

Sound Level Meter

The XL2 provides, together with the measurement microphone, a precise sound level meter for monitoring live soundevents and/or environmental noise.

Extended Acoustic Pack (optional)
The Extended Acoustic Pack offers the following additional features for sound-level and acoustic measurements:

The Type Approval Option upgrades the instrument to the
XL2-TA, the sound level meter dedicated to certified measurements. The XL2 with the M2230 microphone forms a type approved sound level meter offering class 1 performance according IEC61672 (see chapter Options and Accessories)• SLMeter/RTA function- Recording of linear wav-files (24 bit, 48 kHz)- Percentiles for wide band and spectrum with flexible setting from 0.1% to 99.9%- Sound Exposure Level LAE- 100 ms logging- RTA logging of Lmin and Lmax
- Event-triggered audio and data recording- Time weighting: Impulse (LxI, LxIeq with x= A, C, Z)- True peak level in 1/1 and 1/3 octave resolution- Clock-impulse maximum level (TaktMax) in accordancewith DIN 45645-1 and DIN 45657- Impulsiveness detection in accordance with BS4142:2014
and NordTest ACOU 112• FFT function- High-resolution Zoom-FFT with selectable frequency
ranges and resolution up to 0.4 Hz in the range of 5 Hz to
20 kHz• RT60 function- Reverberation time in 1/3 octave resolution• 1/12 octave Spectral Analyzer(requires Spectral Limits Option)- Recording of linear wav-files (24 bit, 48 kHz)For example, Actual, Lmin, Lmax, Leq with frequency weighting A, C and Z and time weighting F and S can be measured
at the same time. All measurement results are simultaneously
available. You may log all acquired level information, including
real-time information, onto the removable SD Card. To complete the documentation of the measured sound pressure levels, the XL2 offers wav-file recording, as well as the facility
to add voice notes for each measurement. The XL2 measurescorrection values between the loudest point of the live eventand the actual measurement positions in accordance with DIN
15905-5 and V-NISSG. In parallel with the wide band parameters, the XL2 measures the real-time spectrum either in 1/1 or
1/3 octave-band resolution. The RTA perfectly suits tasks suchas optimization of sound systems
22

Sound Level Meter

The sound level meter offers different pages:
Page Selection using the Page Button• Press pageto toggle between the 123 SLMeter page
and the RTA page.
Page Selection using the Rotary Wheel• Select the page 123 SLMeter with the rotary wheel• Confirm with enter .

123 SLMeter: Sound Level Meter
Displays the selected broadband sound level results. You canchange the font size of the result. Depending on the font size
chosen, the XL2 shows 3 or 5 results simultaneously. Individual
frequency weighting, time weighting, actual, minimum, maximum and correction values can be chosen for each displayed
result.

.
RTA: Real-Time Spectrum
Displays the 1/3 or 1/1 octave spectrum of the selected soundlevel within the audio band. Additionally the wide band result isshown graphically by a bar.

Reporting: Report Setting
Here you set which sound pressure levels shall be stored in a.txt file after the completed measurement. Choose between:
ALL

Stores all sound pressure levels.

Selected

Stores up to 10 different individually-definedsound pressure levels.

Menu with enabled options

 You have selected the individual sound level meter page.

For details refer to the chapter Reporting.

23

Sound Level Meter

Logging: Setup of Data Logging
The XL2 features a powerful sound level meter data logger,
which allows you to record all required sound level values during the measurement. In the logging page you set which soundpressure levels shall be logged over time. For details refer tothe chapter Logging. Choose between:
ALL

Logs all sound pressure levels.

Selected

Logs up to 10 different individually-defined soundpressure levels.

Event Trigger: Event Setting (optional)
The event function is available with the optional Extended
Acoustic Pack. The XL2 event feature offers the following functionalities:• Automated event triggered at noise levels above/below apreset value including setting markers for specific noise categories. Application example: Recording the noise level for
LAF > 80 dB.
• Event triggered by external key press of the XL2 Input Keypad. You can utilize four keys (1-4) to categorize any noise ofinterest or noise to be later excluded in the post-processing.
A typical application is categorizing any annoying industrial
noise by persons living in the neighborhood.
24

Limit LED: Limit Setting
Here you set the function of the limit LED , thereby highlighting any sound level that exceeds the pre-set limits in orangeor red color. Further, external peripherals are controlled by the
optional Serial I/O Interface based on the sound level, such as
displaying sound levels on a large external red-orange-green
lamp. For details refer to the chapter Limits.

KSET Correction: Setup of Correction Values
This page provides a wizard to measure correction values,
which could be helpful for compliant sound level monitoringof live events. It measures the correction values between
the actual measurement position and the loudest position accessible by the audience. The XL2 displays and logs
the selected sound pressure levels including the correction
values, allowing the sound engineer to monitor the soundlevel at the loudest position in the audience. The measurement meets the requirements of the standards DIN15905-5
and V-NISSG. For details refer to chapter Correction Value
KSET.

Sound Level Meter

Set EQt, L%: Selection of measured levels
This page allows setting the following levels:• Moving Time-average Sound Level
Gliding Leq with selectable time window from one second to
one hour. Four individual levels can be configured. This levelis also called “running Leq,T” or “sliding Leq,T”.
• Percentile Sound Level- Allows the individual configuration of seven statistic levels from 0.1% to 99.9% (optional with Extended Acoustic
Pack).
- The Broadband Source for the calculation of the level statistics can be chosen from a set of different levels witheither a frequency weighting A, C or Z. The time weightings F, S and the moving time-averaged sound level for one
second are supported.

25

Sound Level Meter

Overview
Numeric Result Page
The numeric result page 123 SLMeter displays the selectedbroadband sound level results. You can change the font size ofthe result. Depending on the font size chosen, the XL2 shows
three or five results simultaneously. Individual frequency
weighting, time weighting, actual, minimum, maximum andcorrection values can be chosen for each displayed result.

Real-Time Analyzer Page
The real-time analyzer page
RTA measures and displays
the 1/3 or 1/1 octave spectrum from 6.3 Hz to 20 kHz including
wideband results. The real-time spectrum RTA is measured inparallel with the A and Z-weighted wideband levels.

17

8

9
10

1

11

12
2
3

13
7
6
4

26

16
15

5

14

Sound Level Meter

1

Sound Level Result 1
All sound levels are measured and logged simultaneously.
You select which sound levels should be displayed.

4

Change Parameter• Turn the rotary wheel
to select the parameter Lxx.
• Press enter
to open the selection menu and choose
the wideband sound pressure level to be displayed.
• Turn the rotary wheel
to select the required test result
parameters and confirm with enter .

Select the lowest possible input range according to the
maximum level expected during the measurement; e.g., if
the sound pressure will always be below 110 dBSPL, thenselect the lowest input range 10 - 110 dBSPL.

Change Font Size
• Turn the rotary wheel
to select the actual test result.
• Press enter
1x, 2x or 3x to set the font size to small,medium or large.
5

The XL2 shows 3 sound levels on the display if a large fontis chosen, otherwise it shows 5 sound levels.
2

Sound Level Result 2 & 3
Follow the setting instructions for sound level result 1.

3

Sound Level Result 4 & 5
To display sound level results 4 & 5, choose a smaller fontfor all results. Follow the setting instructions for sound level
result 1.

Input Range
The XL2 Analyzer provides three input ranges to accommodate the wide range of input signals. The individual ranges are based on the microphone sensitivity setting in thecalibration menu of the XL2. For example, at a sensitivity
S=20mV/Pa the input ranges are• Low: 10 - 110 dBSPL• Mid: 30 - 130 dBSPL• High: 50 - 150 dBSPLRun Indication
The run indication shows the measurement status running,paused or stopped. Various measurement settings arelocked during ongoing measurements, such as changing
the input ranging or the preset measurement time.

27

Sound Level Meter

6

Actual Measurement TimeCounts actual measurement time in hrs:min:sec. Supports
time modes: continuous, single and (synchronized) repeat.
Timer Mode Continuous(applicable for standard measurements)
All values are recorded and monitored continuously after starting a measurement with start.
The actual measurement time is shown.
Timer Mode Single
Automatically stops the measurement after the
pre-set measurement time.
• Set the required measurement time.
• Start the measurement.

 The actual measurement time counts back to zero andthe measurement ends.
• All measurement results may be recalled.

28

Timer Mode Repeat
Provides automated repeated measurements withuser-defined, preset measurement time cycles.
• Set the required measurement time.
• Press start.

 The actual measurement time counts back tozero. When the preset measurement time has
elapsed, the measurement time and the measurement results are reset and a new measurement is started. All measurement resultsof the previous cycle are reset.
• Press stop

to complete the measurement.

Sound Level Meter

8

Timer Mode Repeat Synchronized
Providesautomated
repeatedmeasurements synchronized to the XL2 real-time clock.
Press start
to begin the measurement.
In order to align the selected preset measurement
time with the real-time clock, the XL2 shortens
the first cycle to match the real-time clock synchronization. All following measurement cycles
are synchronized to the real-time clock.
For example, the cycle time setting is 30 minutes
and the measurement starts at 7.50 a.m. -> thefirst test cycle measures from 7.50 - 8.00 a.m.
Thereafter a new test cycle starts automaticallyfor 30 minutes. The 30-minute cycles repeat until
the measurement is stopped.
The measurements in the synchronized repeat
timer mode start exactly on the half or full hour inaccordance with DIN 15905.
7

9Phantom Power Supply
48V

The XL2 provides 48 V Phantom power supply
to the connection microphone or sensor.

ASD

An NTi Audio measurement microphone with
automated sensor detection ASD is connected. The XL2 reads the electronic data sheet ofthe microphone and switches the 48 V Phantom power automatically on

48V

Phantom power is switched off.

Result Symbols / CaptureThis field offers two functions:• Symbols for measurement results 15
Upper RTA parameter displayed as line.
Lower RTA parameter displayed as bargraph.

Preset Measurement Time
Adjustment of preset measurement time for single and repeat timer setting.

29

Sound Level Meter• Capture
One of the displayed RTA readings may be captured. Anymeasurement data can then be compared with this captured reference live on the XL2 Analyzer. For example,
compare the RTA spectrum of the left and right speakers.
• Select the parameter to be captured.
• Confirm with enter , to capture the reading.
• Select the upper RTA parameter 15 and choose
Capt.
• Confirm with enter .

 The lower RTA reading can be compared with the previ-

11

Y-Scale setting• Select the Y-Axis with the rotary wheel
and confirm
with enter .
• Select the zoom factor between 20, 10, 5, 2.5 dB/div
and confirm with enter .
• Scroll up and down with the rotary wheel
to select the
Y-axis range.
• Confirm with enter .

12 RTA Measurement Result

Real-time analyzer results in 1/1 octave or 1/3 octave band
resolution. Adjust the resolution at 17 .

ously-captured reference data.
13 X-Scale setting
10 Measurement Result

Actual level result of the indicated frequency band. The cursor readout displays the center frequency and the level ofthe band pointed to by the arrow.

Toggles X-scale range between
20 Hz - 20 kHz

RTA levels including wide band results

6.3 Hz - 8 kHz

RTA levels including wide band results

6.3 Hz - 20 kHz

RTA levels

Upper parameter displayed as line.
Lower parameter displayed as bargraph.
• Select the X-Axis with the rotary wheel
and confirm
with enter .
• Toggle with the rotary wheel
between the ranges.
• Confirm with enter .
30

Sound Level Meter

14 Broadband Results

Actual sound level.
The broadband sound pressure level Leq, Lmin, Lmax andLive are displayed here. The Live level is displayed withtime weighting Fast.
A A-weighted broadband sound pressure level
Z

Broadband sound pressure level without any frequency weighting

15 Readout Frequency

You may select any frequency to read out individual levels.
The selected frequency is indicated by the cursor arrow.
Choose between the following settings:

The cursor readout may be set manually to any
frequency band or wide band level. The readout remains at the selected frequency.
• Select the frequency with the rotary wheel .
• Press enter .
• Select the frequency of interest.
• Confirm with enter .

 The cursor readout 11 displays the measurement results of the selected frequency band.
16 Setting of Test Result Resolution

Set the RTA result display to 1/1 octave or 1/3 octave band
resolution as follows:• Turn the rotary wheel
to select the parameter 17 .
• Press enter
to toggle between 1/1 OCT and 1/3 OCT
and set this parameter.

The cursor follows automatically the highest level,
e.g. tracing feedback frequencies at live sound.
• Select the frequency with the rotary wheel .
• Press enter .
• You may readout any individual frequency.
• Return to auto frequency with enter .

 The cursor returns to the frequency with highest level bar.
31

Sound Level Meter

17 Measurement Unit

Select the measurement unit as follows:dB

Sound level in dBSPLThis measurement unit is permanently selected
when an NTi Audio measurement microphonewith electronic data sheet is connected.

dBu

Input level in dBu

dBV

Input level in dBV

V

Input level in Volt

• The measured sound pressure level is just above the residual
noise of the connected NTi Audio measurement microphone.
This reduces the measurement accuracy -> choose anothermicrophone designed for low level measurements.

LOW - Indication
The low indicator for an individual level “<” is displayed when:• The measured sound pressure level is below the selected
linear measurement range. In this case the results shown
are most likely higher than the actual sound pressure level ->choose the next lower measurement range.
32

The low condition is registered in the log and report files in thecolumn “Low(eq/peak)“ individually for all frequency weightings, the RMS and the peak levels.

Sound Level Meter

Overload Indication
In case the measurement result exceeds the preset measurement range, then limit arrows
indicate this overload condition. The arrows
are displayed for as long as the overload
exists, and at least for a minimum of 1 second. Furthermore,such an overload condition triggers the OVR indication in thebottom line, which remains displayed for the complete measurement period. These overload indications are reset at thestart of a new measurement. All overload conditions are registered in the log and report files.
Possible causes for exceeding measurement ranges are• The measured sound pressure level exceeds the pre-set
measurement range during the measurement period. Once
this happens, the OVR indication remains displayed for thecomplete measurement period -> select the next higher
measurement range or reduce the input signal level as applicable.
• The input level is near the maximum level of the connected
NTi Audio measurement microphone.

33

Sound Level MeterSound Level Meter - Getting Started
Test Preparations• Connect the measurement microphone to the XL2.
• Switch on the XL2 .
The XL2 reads the electronic data sheet of any connected NTi
Audio ASD microphone and switches the 48 V phantom power
automatically.

Select Displayed Test Result
This example describes the setting of the commonly-used actual sound pressure level LAF (level L, frequency weighting A,
time weighting F).
• Select the first parameter setting with the rotary wheel• Confirm with enter .

.

 The 48 V phantom power indication in the upper menu barchanges to ASD. The XL2 is ready for acoustic measurements.
• Position the XL2 at the measurement location using a microphone stand or a tripod.
• Select the SLMeter function in the measurement menu andtoggle with pageto the numeric result page.

All wideband and RTA levels are measured andlogged simultaneously. You select which soundlevels should be displayed.
Press start
to measure and display thesound levels results indicated with ----.

34

Sound Level Meter

Select Frequency Weighting

Select Time Weighting The pop-up window FREQ WEIGHTING appears.

 The pop-up window extends with TIME WEIGHTING.

• Select the frequency weighting A.

• Select the required time weighting; e.g.

(=Fast).

Installation of the Extended Acoustic Option
adds more items to the pop-up window• Confirm with enter.

• Confirm with enter.

35

Sound Level Meter

Select Parameter

Select Correction Value The pop-up window extends with PARAMETER settings.

 The pop-up window extends with CORRECTION settings.

• Select the parameter live.

• Select the parameter off.

• Confirm with enter• Confirm with enter.

.

 The pop-up window closes and the measured sound pressure level LAF is displayed.

36

Sound Level Meter

Select further Sound Levels

Select Input Range• Select the lowest possible input range based on the maximum level expected during the measurement. Wrong input
ranges are indicated by a “<” in front of the measurement
value or a flashing OVR message in the lower menu bar.
• Select the input range RNGE and press enter .
• Turn the rotary wheel to set the applicable input range andconfirm with enter .

The numeric result page and the real-time analyzer page use the same input range.

• Select further sound pressure levels as described above;e.g., LAeq and LAFmax

37

Sound Level Meter

Start Measurement• The XL2 is ready to measure the sound levels LAF, LAeq and
LAFmax.
• Press start.

 The run indication switches to running

Stop Measurement and Data Saving• Press stop.

 The XL2 stores the broadband sound pressure levels andthe real-time analyzer results simultaneously.

. The integrated
sound pressure level over time LAeq and the maximum level in the measurement period LAFmax are displayed. The
parameter RUN, LOG (logging is enabled) or AUD (audio
recording is configured) flashes in the memory menu.

• Press enterto confirm. The measurement data is stored
on the SD Card in ASCII format.

 The sound pressure level measurement is completed.
38

Sound Level Meter

Data Post-Processing
The XL2 stores all data and audio onto the SD card for directtransfer to a computer. Audio data is stored as .wav files. Data
reports and log files are stored in plain text format, which canbe opened with any text editor (Notepad, Wordpad, etc.). The
data is tab-delimited, so dropping the .txt file into a spreadsheet
application will conveniently show the results in columns.
Furthermore, a series of free MS Excel application templates provide a convenient way to view the measurement results of specifictasks and create simple reports. They are available as free download for all registered XL2 customers on the support website athttps://my.nti-audio.com. (Enable all macros when opening the
document.)
For the most comprehensive analysis of logged noise monitoring data, use the XL2 Data Explorer software. The data import
into the software is enabled by the Data Explorer Option, whichneeds to be installed in the XL2 Sound Level Meter. More details in chapter XL2 Data Explorer.

RTA Measurement - Getting Started
Test Preparations
The XL2 reads the electronic data sheet of any connected ASD
microphones provided by NTi Audio and switches the 48 V
phantom power automatically on as follows:• Connect the measurement microphone to the XL2.
• Switch on the XL2 .

 The 48 V phantom power indication in the upper menu barchanges to ASD. The XL2 is ready for acoustic measurements.
• Position the XL2 at the measurement location using a microphone stand or tripod.
• Select the SLMeter function in the measurement menu andtoggle with pageto the real-time analyzer (RTA) page.

All wideband and RTA levels are measured andlogged simultaneously. You select the soundlevels to be displayed.

39

Sound Level Meter

RTA Configuration
The XL2 displays two different sound pressure levels at thesame time. You configure which test results to display; e.g.,
LZFmax and LZFlive.

Select RTA Frequency Weighting The pop-up window FREQ WEIGHTING appears.
• Select the frequency weighting Z.

• Ensure no other measurement is going on. The run indication
should display the stop symbol.
• Select the LZF value with the rotary wheel.

• Confirm with enter.

Press start
to measure and display thesound levels results indicated with ----.
• Confirm with enter
40.

Sound Level Meter

Select RTA Time Weighting The pop-up window extends with TIME WEIGHTING.
• Select the required time weighting; e.g.,(=Fast).

Select Upper/Lower RTA Parameter• Select the parameter shown to the right of the upper LZF
value with the rotary wheel ; e.g. max.
• Press enter .

 The pop-up window PARAMETER appears.
• Select the parameter max.

• Confirm with enter.

• Confirm with enter .
• Follow the same instruction and select the lower RTA parameter live.
41

Sound Level Meter

Select Input Range• Select the lowest possible input range according to the maximum level expected during the measurement. Wrong input
ranges are indicated by a < in front of the measurement value or a flashing OVR message in the lower menu bar.
• Select the input range RNGE and press enter .
• Turn the rotary wheel to set the applicable input range andconfirm with enter .

The numeric result page and the real-time analyzer page use the same input range.

42

Start RTA Measurement• The XL2 is ready to display the measured sound pressurelevels LZFmax and LZFlive.
• Press start.

 The run indication switches to running. The actual soundlevel LZFlive and the maximum level LAFmax are displayed.
The parameter RUN , LOG (logging is enabled) or AUD (audio recording is configured) flashes in the memory menu.

Sound Level Meter

Stop the Measurement and Data Saving• Press stop.

 The XL2 stores the broadband sound pressure levels andthe real-time analyzer results simultaneously.

ReportingA report saves the conducted measurements onto the installed
SD Card. The XL2 Supports setting the individual levels to be
stored in the report after the measurement is completed.

123• Press enterto confirm. The measurement data is stored
on the SD Card in ASCII format.

 The RTA measurement is completed.

1

Add Spectra
No

No RTA measurement reporting.

Leq

The RTA Leq level is stored in the report.
43

Sound Level Meter

Leq, Lmax, The RTA Leq, Lmin, Lmax levels are stored
Lminin the report.
All
2

All RTA levels are stored in the report.

Report Values
Choose between the following result reporting:ALL

Records all available sound pressure levels
without correction values.

Selected

Records a subset of up to 10 different levels,
including correction values if you require.

6

 The pop-up window for level selection appears.

44

1
2
3
5

Selected Report Values• By setting Selected at 2 up to 10 individual report values can be chosen. Select the first value Lxx with therotary wheel
and press enter .

• Select the reporting level with the rotary wheel
confirm with enter .

The XL2 features a powerful sound level meter data logger,
which allows you to record all required sound level values during the selected period of time. All results are logged onto the
SD Card. The measurement results can be loaded to a PC for
documentation and visualization. The LOG menu offers the detailed setup of the log report.

4• Select Report Values with the rotary wheel .
• Press enter
to toggle between All or Selected.
3

Loggingand7Sound Level Meter

1

Logging
Select Logging with the rotary wheel
and press enter
to enable the automated logging of test results.
On

The XL2 logs measurement data every interval
dt 2 .

Off

No Logging

2

Interval Dt
Adjust the logging interval. The optional Extended Acoustic
Pack offers the additional 100 ms logging.

3

Add Spectra
Set the RTA logging for each logging interval here.

4

Log Audio
The XL2 logs audio data as a wav-file. Choose among thefollowing settings:
Off

Audio logging is off

On

Audio logging is activate from measurement start to stop.

Events Only

Audio logging of triggered eventsonly.

For more details read the chapters Wav-File Recording andEvents.

No

No RTA spectrum is logged.

FormatChoose among the following audio recording settings:

Leq

The Leq spectrum is logged.

Compressed

Compressed audio logging

Leq, Lmax,
Lmin

The Leq, Lmax and Lmin spectrum islogged simulatenuously (requires optional
Extended Acoustic Pack).

Compressed+AGC

Compressed audio logging with
automated gain control

24Bit_48kHz

Linear audio logging in 24 bit,
48 kHz resolution (optional with
Extended Acoustic Pack)

5

45

Sound Level Meter

6

Wav-File Recording

Log Value Setting
Choose between the following settings:
ALL

Logs all available sound pressure levels without correction values.

Selected

Logs a subset of up to 10 different soundpressure levels, including correction values if
you require.

• Select Log Values with the rotary wheel .
• Press enter
to toggle between All and Selected.
7

Selected Log Values
By setting Selected at 5 up to 10 individual log values canbe chosen.
• Select the first value Lxx with the rotary wheel
andpress enter .

 The pop-up window for level selection appears.
• Select the logging level with the rotary wheel
firm with enter .

and con-At 100ms Logging is the log value selection limited to fivedifferent parameters.
46

The XL2 records a wav-file of the measured input signal andstores it on the SD Card. The available formats are:• Compressed (default, using ADPCM compression). A new
wav-file is started automatically after 12 hours of recording(typical maximum wav-file size = 512 MByte)• Compressed+AGC, compressed with automated gain control. The gain control increases the level of low-level signals,
so that the wav-file is well-leveled during playback on thePC.
• 24Bit_48kHz, linear wav-file logging in 24 bit, 48kHz resolution with the optional Extended Acoustic Pack. A new wavfile is started automatically after 1 hour of recording (typicalmaximum wav-file size = 512 MByte)

Broadcast Wave Format BWF
The XL2 stores scaling factor, serial number,date, time and time zone within the wav-file (according to EBU TECH 3285). This information isavailable through professional audio/video tools
typically used in broadcast.

Sound Level Meter

Sample name of wav-file:
MyTest_SLM_000_Audio_FS133.0dB(PK)_00.wav

1

2

3

4

5

1

MyTestFile name defined by user.

2

SLM
Measurement function.

3000
Automatically incrementing file number.

4

Audio_FS133.0dB(PK)
Audio file with full scale peak level. In case of a Compressed + AGC recording, the file name reads “AGC”; thisfile contains corrected level information only.

500
For wav-file recording over longer periods, the XL2 splits
the audio data into individual wav-files with about 500 MB(compressed audio: 12 hours; linear: 1 hour), keeping thefile size small for easier handling on the PC. The number 5
increments for each successive wav-file.

The advantage of wav-file recordings is to identify and document sound sources after the measurement. For example, ata live event an excessive peak level may have been measured
and logged. Actually, this peak level was caused by people
shouting nearby the measurement microphone, and not by theaudio system being monitored. The recorded wav-file assists inverifying this and the test results can then be post-processed.

Pausing Measurement
If any ongoing measurement is paused, the
XL2 continues the recording of wav-files during
the paused period. The logged data and audio
data can be synchronized using the stored realtime information.
Events
The wav-files are stored in a folder, named, forexample,2011-11-30_SLM_000_AudioEvent_0001-0200.
The actual wav-files are named for example, as
xxxx_FS133.0dB(PK).wav (xxxx = incrementing
number)47

Sound Level Meter

Another example is environmental noise monitoring: Listening
to the recorded wav-file after the measurement may help todetermine the predominant sound source. The XL2 Analyzer
preserves the original absolute test signal level in the recorded
wav-file.
The XL2 Analyzer provides three input ranges to accommodate the wide range of input signals. The dynamic rangeof the recorded wav-file is set according to the selected input range. For example, at a microphone sensitivity of
S= 20 mV/Pa, the full-scale peak level is:48

Range Name

Range Level

Full-scale peak level

Low

10 - 110 dBSPL

117.8 dBSPL

Mid

30 - 130 dBSPL

135.9 dBSPL

High

50 - 150 dBSPL

159.9 dBSPL

Select the lowest possible input range according to the maximum level expected during themeasurement; e.g., If the sound pressure will
always be below 110 dBSPL, select the lowest
input range 10 - 110 dBSPL.

Sound Level Meter

Events (optional)
The event function is available with the XL2 Extended Acoustic
Pack Option. The XL2 Analyzer may be configured to record
wav-files and additional noise levels only when triggered, instead of the complete measurement duration.
Advantages
Reduces the data volume acquired, thereby• Simplifying data post-processing• Saving memory for long-term measurement applications.
EventsEvents are triggered either automatically by sound levels above/
below a preset value or manually by external key press using
the XL2 Input Keypad.

Data Logging
The XL2 Analyzer logs the data specified in the
LOG setting for the complete measurement duration into a log file. The markers and triggered
events results are added to the same log file.
The XL2 Input Keypad is available as an accessory. Please see chapter Options and Accessories for details.

Recommendation
With the large storage capacity of the XL2, NTi Audio recommends logging at a 1 second or faster interval. This allows theaccurate collection of event data; one event will be stored within a logged interval. If results for reporting are required at longer intervals, e.g. one hour, the XL2 Data Explorer software isrecommended. It easily combines logged data into longer audit
intervals. An additional advantage of a faster logging interval isthat only an entire logged interval can be excluded from theaverage. This is useful when a qualified noise consultant judgesthat a sound is not caused by the object under test or is not a
normal sound for a measurement location.
Functions
The XL2 event feature offers the following functionalities:• Automated event triggered at noise levels above/below apreset value including setting markers for specific noise categories. Application example: Recording the noise level for
LAF > 80 dB.
• Event triggered by external key press of the XL2 Input Keypad. You can utilize four keys (1-4) to categorize any noise ofinterest or noise to be later excluded in the post-processing.
A typical application is categorizing any annoying industrial
noise by persons living in the neighborhood.

49Sound Level Meter

Trigger Events: on level above/below
14

90

Event Duration

Level [dB]

100

1

2 80

13

3

12

4

14
3 70
60

2

5
13

12

6
7
8

Time [seconds]

9
10

Features:• The levels LAeq, LZeq and LCPeak are recorded for the event
duration.
• Audio data is recorded for the triggered event duration only,
thus simplifying data post-processing and saving memory
space for long-term measurements.
• Setting markers by external key press of the XL2 Input Keypad.
50

11Sound Level Meter

1

2

Trigger Events
Choose from the following settings:
OffNo event triggering

on levelabove

Events are triggered at noise levels above thepreset value 2 for the start duration 13 .

on levelbelow

Events are triggered at noise levels below thepreset value 2 for the start duration 13 .

on ext.
key
press

Events are triggered by external key press.

3

on levelabove

Stop level = Start level 2 - Hysteresis 14

on levelbelow

Stop level = Start level 2 + Hysteresis 14

Stop Duration 12
The event stop is triggered when the noise level is lower (orhigher) than the preset value and continues for the preset
duration.
Hysteresis 14
Set the hysteresis to an appropriate value to prevent rapid
switching on and off as the level drifts around the Startlevel.

Start [dB]
Set the level at which the triggered event is started.
Start Duration 13
The event start is triggered when the noise level is higher(or lower) than the preset value and continues for the preset duration.

Stop [dB]
Set the level at which the triggered event is stopped.

4

Level Selection
Define the level type to be monitored.

51

Sound Level Meter

5

Log Audio
The XL2 logs audio data as a wav-file. Choose from the following settings:
Off

Audio logging is off

On

Audio logging is activated frommeasurement start to stop.

Events Only

7

Recordingwhole event

Records a wav-file for the whole triggered event duration.

Stop recording
after

Records a wav-file for the specified
period after the event start is triggered.

Audio logging of triggered events
only.
8

Status Information
Displays current trigger status:• Waiting for trigger• Armed (during start duration 13 )• Audio + data recording• Completing log cycle

9

Actual Level
Measurement result of the defined level 4 .

For more details read the chapter Wav-File Recording.
6

Audio Logging Period
If Log Audio 5 is set to Events Only, then the duration
for the audio recording may be further specified:

FormatChoose from the following audio recording formats:Compressed

Compressed audio logging

Compressed+AGC

Compressed audio logging with
Automated Gain Control (AGC)

24Bit_48kHz

Linear audio logging in 24 bit,
48 kHz resolution. (Required forpost-processing on the PC with
Extended Acoustic Pack)

10 Event Counter

52

Counts the number of triggered events that have occurred
during the ongoing measurement.

Sound Level Meter

Event automatically triggered by level.

1

Event triggered or marker added by pressing key 1of the XL2 Input Keypad.

100

2

Event triggered or marker added by pressing key 2of the XL2 Input Keypad.

3

Event triggered or marker added by pressing key 3of the XL2 Input Keypad.

4

Event triggered or marker added by pressing key 4of the XL2 Input Keypad.

90

Event Duration

Event Duration

15

15

80

70

60

key press

Lvl

Trigger Events: on external key press
Trigger Events by pressing a button on the external input keypad with automated or manual stop of the event.

key press

Trigger and Marker Monitor
Answers the question: What caused the triggered event?

Level [dB]11Time [seconds]

12 Stop Duration

See 3 .
13 Start Duration

See 2 .
14 Hysteresis

See 3 .

Features:• The levels LAeq, LZeq and LCPeak are recorded for the event
duration.
• Audio data may be recorded for the user-defined event duration 15 after the key press.
• Retrigger with every repeated key press within the event
duration.
53

Sound Level Meter

15 Event Stop Mode and Event Duration

15
16

on key release

The event is recorded as long as the
button of the input keypad is keptpressed; the Event period is at leastMin. Event Duration long.

on ext. keypress

The event is stopped by pressing a button on the external input keypad; theEvent period is at most Max. Event
Duration long.

16 Button Functionality of Input Keypad

54

treat each key
separately

All four buttons operate individually.
For example pressing the button 2
will be recorded as button 2 in themeasurement report. This allows you
to distinguish different acoustic noise
sources.

treat all keys as
Key 1

All four buttons operate in parallel andany button press will be recorded as
button 1 in the measurement report.

Sound Level Meter

How to Setup the XL2 for Triggered Event Measurements• Select the logging page, set Logging On, Interval dt:
00:00:01 and choose the required log values.
• Setup the event page. For example, the screenshot below
starts the event recording after LAF exceeds 80 dB for 2 seconds and stops after LAF is lower than 70 dB for 3 seconds.

Logging Enabled
Triggered-event recording requires the activation of sound level logging. Using the default
Interval dt: 1 second is recommended.
Auto Save
If Log Audio 5 is set to Events Only, thenthe XL2 sets per default Naming+Saving: autoin the memory menu. This ensures that the recorded triggered event data is stored on the SD
Card.
For convenience, in case more than 20 triggered
events have been recorded, the Autosave ->Delete function is disabled, as deleting such
multiple wav-files on the XL2 is time-consuming.
Wav-files
All triggered-event wav-files are stored in an individual folder. For details see chapter Logging.

• Select the memory menu and create a new folder. This folder
will then be displayed in the memory menu. All log data andevent wav-files are stored in this folder.

 The XL2 is ready for the triggered event measurement.
55

Sound Level Meter

Limits1

The limit page offers two functions:• Setup of limit LED
function; enabling the XL2 to highlight
any sound levels that exceed the pre-set limit in orange or
red color. The default color is green.
• Limit parameter setup for external connected accessories,
such as the Digital I/O Adapter PCB, the Limit Light or the
Stack Light. These accessories connect to the digital I/O interface of the XL2.

LED - Level 1
Select one sound level for the limit LED indication .
• Select the sound level field with the rotary wheel .
• Press enterand select the sound level for the limit
LED indication.

3

Selected Level Values
To set the level values for the limit LED ,• Select the Red or Orange sound level with the rotarywheel
and press enter .
• Set the level value with the rotary wheel
and confirm
with enter .

4

Digital I/O On/Off
Select Digital I/O with the rotary wheel
and press enter
to enable/disable the operation of externally connected
accessories.

8

3

4
5
6

56

7

and press enter2

1
2

Limit LED On/Off
Select Limit LED with the rotary wheel
to enable/disable the limit function.

Sound Level Meter5

I/O - Level 1
Setup of the level type 1, which is used to trigger externallyconnected accessories.
• Select the level field with the rotary wheel .
• Press enterand select the level for the control of theexternal accessory.

6

Selected Sound Level Values
To set the level values for the control of the externally connected accessory.
• Select the Out 1, Out 2, Out 3 or Out 4 level with the rotary wheel
and press enter . The Limit Light and theStack Light use Out 1 for red, Out 2 for yellow and Out
3 for green light.
• Set the level value with the rotary wheel
and confirm
with enter .

7

I/O - Level 2
Follow the setting for I/O - Level 1. The I/O level 1 may be
combined with I/O level 2 using and/or combinations, providing indications in level ranges. Alternatively, other levels
can be selected for the control of the externally connected
accessories.

8

LED - Level 2
Follow the setting for LED - Level 1.

I/O Limits with Triggered Events
If event recording is enabled, the digital output
4 (Out 4) is utilized, e.g. as confirmation feedback to the XL2 Input Keypad. Therefore thelimit setting of Out 4 is disabled.

57

Sound Level Meter

Correction Value KSET

1

The correction value page offers a measurement wizard for live
event monitoring, applicable in case the measurement locationdiffers from the loudest position in the live event area.
Measurement Position
The goal at live event monitoring is to measure the sound levelat the loudest position accessible by the audience. Setting up
any sound level measurement at this loudest location is typically not practical, thus an alternative measurement position ischosen. The recommended measurement position in order tominimize the influence that audience noise has on the measurement:• Mount the measurement microphone in front of the main
speakers• Position the XL2 Analyzer at front of house (FOH)• Connect the XL2 Analyzer and measurement microphoneusing a professional audio cable

Positioning the measurement microphone at
front of house (FOH) may result in audience
noise interfering with the measurement results.
The audience noise will be further amplified by
the measured k-values.
58

2

1

Correction k1
The correction k1 is based on the LAeq.

2

Correction k2
Select the level type for correction k2.
LCpeakfor Germany DIN15905-5;
correction is based on LCpeak measurement

LCeq

correction is based on LCeq measurement

Sound Level Meter

Level Difference
Prior to the start of the live event, the level difference between
the loudest and the measurement position is measured. The
XL2 Analyzer calculates the level difference automatically basedon the individual sound level measurements at both locations.
This level difference is included in the sound level reading during the live event, and the XL2 thereby displays and records thesound pressure level of the loudest point.

How to Measure the Correction Value• Play a Pink noise signal at the typical sound level of the live
event (signal source: Minirator or NTi Audio Test CD or or
USB Flash Drive)• Select the correction page.
• Search the audience area for the location with the highest
sound pressure level and position the XL2 Analyzer.
• Turn the rotary wheel
to select the parameter RUN next
to Audience, select LA, LC or LA&LC and press enter .

Measurement
Position(Microphone)
Level difference
audience area

XL2 positioned at FOH

LoudestAudience
Position The XL2 measures the sound level at the loudest position
for 15 seconds. The timer counts down to zero.
59Sound Level Meter• Wait until the measurement is completed.
• Position the XL2 at the measurement position.
• Turn the rotary wheel
to select the parameter RUN next
to Measure, select LA, LC or LA&LC and press enter .

 The XL2 measures the sound level at the measurement
position for 15 seconds. The timer counts down to zero.

60• Wait until the measurement is completed.
• The correction values k1 and k2 are calculated and displayed
including date and time.

Sound Level Meter

Manual Setting of Correction Values
You may fine-tune the correction values k1 and k2 manually.
Such fine-tuning adds the remark “Manually Adjusted” in thelog file.

• Set the correction value with the rotary wheel.

 The note “Manually Adjusted” is displayed at 2 .
• To undo the manual setting turn the rotary wheel
the parameter UNDO at 2 .
• Confirm with enter .

to select

Reset Correction Values
You may clear all correction values back to zeroby pressing the Clear All 1 and confirm withenter .
3
1

• Turn the rotary wheel
and press enter .

Display k1 and k2 during Measurement
The correction values k1 and k2 can be displayed in the numeric result page during the ongoing sound level measurement instead of any
other sound levels.

2

to select the correction value The selected correction value starts flashing.

3

Correction Values in Profiles
The correction values k1 and k2 can optionallybe stored within profiles. Loading the profile,sets the stored correction values.

61Sound Level Meter

Locked Run Mode
The Locked Run Mode simplifies sound level monitoring. You
just need to power up the XL2 and the measurement starts
automatically. The measurement continues until you switch off
the instrument using the power button . The measurement
data is stored by default.

• The page button
allows toggling between the sound level meter and real time analyzer window. All other buttons aredeactivated during Locked Run Mode.

Start Locked Run Mode
• Set the required parameters in the sound level meter foryour noise monitoring application.
• Press and hold the start/stop button
for 3 seconds.

 The Locked Run Mode is now activated. The Run Indicator
1 displays L. The Info window is displayed at the same
time.

1

• Switch off the instrument.

 The measurement is stopped and the data is saved.
• Switch on the instrument.

End Locked Run Mode
• Press and hold the start/stop button
the ongoing measurement.

 The sound level measurement starts automatically and The measurement is stopped and the Locked Run Modecontinues as long as the device is powered on.
62

deactivated.

for 3 seconds duringSound Level Meter

63

FFT Analysis + Tolerance

5.

Acoustic Analyzer

Besides the comprehensive sound level meter functions, theXL2 Audio and Acoustic Analyzer offers the following acoustic
measurement functions:• FFT Analysis with optional tolerance function• Reverberation Time
• Polarity• Delay time• 1/12 Octave + Tolerance Analysis (optional)• Noise Curves (optional)• Speech intelligibility STIPA (optional)

64

FFT Analysis + Tolerance
The FFT measurement is the ideal tool for visualization of comb
filters and narrow band effects. It allows a detailed frequency
response investigation of audio and acoustic systems. The XL2
includes an extremely fast, real-time FFT. Optional featuresare• High-resolution Zoom-FFT up to 0.4 Hz steps in the frequency range 5 Hz - 20 kHz provided with optional Extended
Acoustic Pack or the Spectral Limits Option• Capture and tolerance function provided with Spectral Limits
Option; thus the main menu function reads FFT + Tol.

FFT Analysis + Tolerance

1

14

13

12

Result Symbols / Capture & Start Tolerance Mode
This field offers two functions:• Symbols for measurement results 2
Upper result displayed as line.
Lower result displayed as bargraph.

11

1

10

2

• Capture & Start Tolerance Mode
The displayed readings may be captured as reference
reading C1 to C8 for• Comparing measurement results against captured
traces with relative or absolute curve display.
• Creating tolerance masks based on captured reference curves for passed / failed measurements.

3

4

9
8
5

6

7

Capture EQ

Captures the upper parameter

Capture Live

Captures the lower parameter

65

FFT Analysis + ToleranceManagecaptures

Allows to rename captures, clear recorded captures, save captures to the
SD Card for export from the XL2 orload captures from the SD Card for import to the XL2.

Start tolerance Starts the tolerance mode for passed/mode
failed measurements comparing theactual measurement results against atolerance band.
2

Measurement Result
Actual level result of the indicated frequency band. The cursor readout displays the center frequency and the level ofthe band indicated by the arrow.
Upper parameter displayed as line.
Lower parameter displayed as bargraph.

3

Y-Scale setting• Select the Y-Axis with the rotary wheel
and confirm
with enter .
• Select the zoom factor between 20, 10, 5, 2.5 dB/div
and confirm with enter .
• Scroll up and down with the rotary wheel
to select the
Y-axis range.
• Confirm with enter .

4

Measurement Result
Displays the actual and averaged measurement results.

5

Input Range
The XL2 Analyzer provides three input ranges to accommodate the wide range of input signals. The individual ranges are based on the microphone sensitivity setting in thecalibration menu of the XL2. For example at a sensitivity
S=20mV/Pa the input ranges are• Lower range: 10 - 110 dBSPL• Middle range: 30 - 130 dBSPL• Upper range: 50 - 150 dBSPL
Select the lowest possible input range according to the
maximum level expected during the measurement; e.g., if
the sound pressure will be always below 110 dBSPL, thenselect the lowest input range 10 - 110 dBSPL.

66

FFT Analysis + Tolerance

6

7Time Weighting
Offers selectable time weighting of 0.1, 0.2, 0.5, 1.0 second as well FAST (125 ms) and SLOW (1 second). Applications:Short Time
WeightingHigh-resolution in time with minimum
averaging

Long Time
Weighting

Low resolution in time with longer averaging

Run Indication
The run indication shows the measurement status running,paused or stopped. Various measurement settings arelocked during ongoing measurements, such as changing
the input ranging or the preset measurement time.
For passed/failed measurements with the Spectral Limits
option the run indication may display A for a preset automated level trigger.

8

Actual Measurement TimeCounts actual measurement time in hrs:min:sec. Supports
setting of time modes: continuous and single.
Timer Mode Continuous(applicable for standard measurements)
All values are recorded and monitored continuously after starting a measurement with start.
The actual measurement time is shown.
Timer Mode Single
Automatically stops the measurement after the
pre-set measurement time.
• Set the required measurement time.
• Start the measurement.

9

Preset Measurement Time
Adjustment of preset measurement time for single timer
setting.

67

FFT Analysis + Tolerance

10 Readout Frequency

11

You may select any frequency to read out individual levels.
The selected frequency is indicated by the cursor arrow.
Choose between the following settings:• Select the readout frequency 10 and press enter .
• The zoom mode is displayed above the flashing arrow.
• Select the zoom-in frequency with the rotary wheel .
• Press limit
and zoom the linear frequency scale in orout with the rotary wheel .
• Release limit
and scroll the linear frequency scale leftor right with the rotary wheel .

The cursor follows automatically the highest level,
e.g. tracing feedback frequencies at live sound.
• Select the frequency with the rotary wheel .
• Press enter .
• You may readout any individual frequency.
• Return to auto frequency with enter .

 The cursor returns to the frequency with high-Zoom Mode(optional, applicable with the Extended Acoustic Pack or
the Spectral Limits Option)

12

Phantom Power Supply

est level bar.
The cursor readout may be set manually to any
frequency. The readout remains at the selected frequency.
• Select the frequency with the rotary wheel .
• Press enter .
• Select the frequency of interest.
• Confirm with enter .

 The cursor readout 2 displays the measurement results of the selected frequency band.

68

48V

The XL2 provides 48 V Phantom power supply
to the connection microphone or sensor.

ASD

An NTi Audio measurement microphone with
automated sensor detection ASD is connected. The XL2 reads the electronic data sheet ofthe microphone and switches the 48 V Phantom power automatically on

48V

Phantom power is switched off.

FFT Analysis + Tolerance

13

Measurement Unit
Select the measurement unit as follows:dB

Sound level in dBSPLThis measurement unit is permanently selected
upon connecting a NTi Audio measurement microphone with electronic data sheet.

dBu

Input level in dBu

dBV

Input level in dBV

V

Input level in Volt

14

Page Selector X-Scale and Parameter Setting
20k

Shows FFT result of the frequency band range.
484.38 Hz - 20.453 kHz in a resolution of
140.62 Hz with 143 bins shown on the display.

1k7

Shows FFT result of the frequency band range.
58 Hz - 1.722 kHz in a resolution of 11.72 Hz with143 bins shown on the display.

200

Shows FFT result of the frequency band range.
7 Hz - 215.01 Hz in a resolution of 1.46 Hz with 143
bins shown on the display.

Usr

User Range(applicable with optional Extended Acoustic Pack
or Spectral Limits Option)
5 Hz - 20 kHz in zoom mode with a minimum resolution of 0.366 Hz and 143 bins displayed.

Set

Selection for FFT Windowing:• Hann: Default for acoustic measurements• Dolph-Chebyshev: for analyzing small signals(e.g. harmonics) close to a dominant signal.

The page button

switches these display modes.
69

FFT Analysis + Tolerance

FFT Analysis - Getting Started
Test Preparations• Connect the measurement microphone to the XL2.
• Switch on the XL2 .

 The 48 V Phantom power indication in the upper menu bar

Configuration
The XL2 displays two different sound pressure levels at thesame time. You configure to display either the levels Live,
Max, Min, EQ or captured results.
• Select the upper result parameter with the rotary wheelchanges to ASD. The XL2 is ready for acoustic measurements.
• Position the XL2 at the measurement location using a microphone stand or tripod.

• Confirm with enter

70

.

.

FFT Analysis + Tolerance

Select Upper/Lower Reading The pop-up window Select reading appears.

 The pop-up window Select reading mode appears.

• Select the integrated averaged reading EQ. All available selections are Z-weighted (= no weighting).

• Select EQ for normal absolute display of measurements.
• Follow the same instruction and select the lower FFT reading Live.
• Confirm with enter.
Press start
to measure and display thesound levels results indicated with ----.

71

FFT Analysis + Tolerance

Select Input Range• Select the lowest possible input range according to the maximum level expected during the measurement.
• Select the input range RNGE and press enter .
• Turn the rotary wheel to set the applicable input range andconfirm with enter .

Start Measurement• The XL2 measures the selected sound pressure levels Live and EQ. All available sound levels are
Z-weighted (= no weighting).
• Press start.

 The run indication switches to running. The actual soundlevel Live and the averaged level EQ are displayed. The parameter RUN flashes in the memory menu.

72

FFT Analysis + Tolerance

Stop Measurement and Data Saving• Press stop.

 The XL2 stores the measurement data automatically.

Audio Recording
The XL2 Analyzer may record a linear audio file (48 kHz, 24 Bit)of the measurement period together with the FFT data. Justload a txt-file named “fftaudio.txt” in the root directory of the
XL2. This requires the installed option Extend Acoustic Pack.
Capture References and Create Tolerances
The Spectral Limits Option extends the function range of the
XL2 with trace capturing, relative curve display and comprehensive tolerance handling for the FFT Analysis and the highresolution 1/12 Oct + Tol spectral analysis.

• Press enterto confirm. The measurement data is stored
on the SD Card in ASCII format.

 The measurement is completed.

Features:• Captures multiple traces in the internal memory• Comparing measurement results against captured traces
with relative or absolute curve display• Comprehensive tolerance handling• Creating tolerance masks based on captured reference
curves for passed / failed measurements• Export and import of tolerance and capture files• True peak level in 1/1 and 1/3 octave resolution• High-resolution Zoom-FFT up to 0.4 Hz steps in the frequency range 5 Hz - 20 kHz
Read the detailed description in the separate chapter
Capture + Tolerance.
73

Reverberation Time RT60

Reverberation TimeThe XL2 measures the energy decay from 63 Hz to
8 kHz using the Schroeder method in 1/1 octave resolution. The
optional Extended Acoustic Pack enables 1/3 octave band resolution from 50 Hz to 10 kHz. Use either an impulse source (e.g.,a starter pistol) or an interrupted pink noise as the test signal.
What is Reverberation Time?
Reverberation time is the time required for the sound pressure level to decrease by 60 dB after the sound stimulus signal
is stopped. For simple practical measurements the applicablestandard ISO 3382 and ASTM E2235 specifies the following
two measurement methods:• T20- The measurement requires just a small dynamic measurement range of ~35 dB above the ambient noise level foreach frequency band.
- RT60 (T20) = 3 x decay time of 20 dB• T30- The measurement requires a dynamic measurement
range of ~45 dB above the ambient noise level for eachfrequency band.
- RT60 (T30) = 2 x decay time of 30 dB

In detail, the reverberation time is based on a linear leastsquares regression of the measured decay curve. If theoverall reverberation time is short (e.g. < 0.3 seconds)
the room acoustic is referred to as being “dead”; for example, a heavily furnished room with thick carpets, curtains and upholstered furniture may have such an acoustic character. If the overall reverberation time is long (e.g. >2 seconds) the room acoustic is referred to as being “live” andechoic; for example, a large empty room with painted plasterwalls and a tiled floor may have such an acoustic character.
Level [dB]

0 dB
-5 dB

distance tonoise floor

20 dB level range toobtain the reverberation time

-25 dB-35 dBTime

Reverberation Time Measurement with T20 method
74

Reverberation Time RT60

RT60 Run Test Page

RT60 Result Page

12

11

1

10

18

9
8

17
13
14

7

15

6
16
5

2

4
3

75

Reverberation Time RT60

RT60 Cycle Result Page

1

Set Level Markers
Prior to conducting a reverberation time measurement, theenvironmental noise is measured, and the required energy
level of the test signal is determined.
• Select SET and press entervironmental noise.

22

21

to measure the actual en- The required level markers appear in grey color.
2

Input Range
Select between the lower, mid and upper input range. The
exact ranges depend on the microphone sensitivity settingin the calibration menu of the XL2.

3

Run Indication
This icon displays the running and stop status of the reverberation time measurement. It is controlled by start/stop
.

19

20

76

Reverberation Time RT60

4

Measurement Status STAT
Displays the actual measurement status. Start and stop thereverberation time measurement with start/stop. The
following status information is displayed:
ARMED

5

Measurement is waiting for the test signal
to exceed at least one measurement trigger
marker, then the measurement is triggered
automatically.

NOISE

A sound stimulus signal above the trigger
marker is being received.

DECAY

Decay is being measured.

PAUSE

The measurement has been paused by pressing pause.

STOP

No Reverberation time measurement is presently being performed.

Average AVRGCounts the measurement cycles. When using an interrupted noise test signal, a minimum of 3 sequential cycles isrecommended.

6

Actual Real-Time Spectrum
The black bars indicate the actual signal, including background noise. While setting up the reverberation time measurement you should increase the test signal level until theblack bars exceed the grey bars completely and the status
4 displays NOISE.

7

Level Marker
The grey bars indicate the signal level required for effective
reverberation time measurements in each octave band.
The marker has a length of 35 dB, and can be set by• Selecting SET 1 with the rotary wheel .
• Press enter
to measure the environmental noise in
the silent room.

8

Band Status
Indicates a successful reverberation time measurement
above each octave band with a tick .

9

Measurement Method
Select between the measurement methods T20 and T30.
T20 requires just a small dynamic measurement range of~35 dB above the ambient noise level for each frequency band. T30 requires a dynamic measurement range of~45 dB.

77

Reverberation Time RT60

10 Measurement Resolution

Reverberation time measurement selectable in 1/3 octave or 1/1 octave band resolution. The optional Extended
Acoustic Pack enables 1/3 octave band resolution from50 Hz to 10 kHz.
1112 Page Selector

Select between the RT60 run test page and the result page.
The page button
toggles between these displays.
RT60 run test page

Phantom Power Supply
48V

The XL2 provides 48 V Phantom power supply
to the connection microphone or sensor.

ASD

An NTi Audio measurement microphone with
automated sensor detection ASD is connected. The XL2 reads the electronic data sheet ofthe microphone and switches the 48 V Phantom power automatically on

48V

RT60 result page. Toggle with the measurement
result selection 18 among
AVRG

RT60 result page showing averageof all cycles and uncertainty factor

CYC xx

RT60 result page for each cycle

Last

RT60 result page for last cycle

Phantom power is switched off.
14 Y-Axis Reverberation Time

Reverberation time in seconds. The scaling is automaticallyadjusted.

78

Reverberation Time RT60

14 Uncertainty Factor

The uncertainty factor is displayed in the RT60 average result page. It indicates the uncertainty of the averaged measurement results, reduces as more cycles are measured,and depends on the measured reverberation time and the
bandwidth of the individual frequency band; lower bands
show a higher uncertainty factor. The number of measurement cycles is displayed at 5 .
15 Overall Reverberation Time Test Result

18 Measurement Result Selection

The reverberation time measurement function allows consecutive measurements within one test sequence. An
averaged test result of all measurements is automaticallycalculated.
Select CYC and scroll with the rotary wheel
individual test result cycles showing
Last

Last Test Result
Displays the result of last measurement cycle.

xx

Single Test Cycle Results
The individual single test results are marked
with CYC xx, where xx is an incriminating number. You may delete individual test results. The
averaged reverberation time result uses only theremaining valid measurements. To delete results
in a cycle,• Select DEL with the rotary wheel• Confirm with enter .

AVRG

Averaged Test Result
The averaged test results of all cycles are calculated and displayed.

Readout of reverberation time and uncertainty factor.
Uncertainty factor. For more details see 14 .
Reverberation time measurement results.
16 X-Axis

Octave Bands 63 Hz - 8 kHz
17 Cursor Readout

Select the individual frequency band and read out the following numeric measurement results• Uncertainty factor in % or correlation in %.
• Reverberation time RT60 (T20), of the selected frequency band, in seconds (s).

through the79Reverberation Time RT60

19 Correlation Factor in %The correlation factor is 100% for perfectly linear soundpressure level decay after the sound source has ceased.
The natural deviation from this linearity results in lower
correlation values. The correlation factor is typically 80 100%.
20 Cycle Reverberation Time Test Result

Readout of cycle reverberation time and correlation factor
19 when selection 18 is CYC xx or Last.
Correlation Factor. Scale is on the right Y-axis. For
more details see 19 .
Reverberation time measurement result of individual displayed cycle. Scale is on the left Y-axis.
21 Y-Axis Correlation Factor

The right Y-axis shows the correlation factor in %. The correlation factor Y-axis is displayed when test result selection
18 is CYC xx or Last.
22 Delete Cycle Results

Individual cycle results may be deleted, thereby excluding
them from the calculation of the AVRG result.

80

Test Signals
Use either an interrupted pink noise or an impulse source as the test signal.
• Interrupted pink noise
Precision measurements require an omni-directional speaker with identical radiation characteristic in all directions. Various interrupted
pink noise test signals with different on/off
times are offered on the NTi Audio Test CD
or USB Flash Drive (included with the XL2) or
the Minirator signal generator. Test signals areavailable for download at https://my.nti-audio.
com/support/xl2. A minimum of three measurement cycles shall be performed. The XL2
averages these readings automatically.
• Impulse
The trigger signal is an impulse source, suchas a starter pistol, starter clap or bursting balloon. Individual measurements, or test sequences with repeated trigger signals, can be
carried out.

Reverberation Time RT60

RT60 Measurement - Getting Started
Test Signal: Pink Noise
Play a pink noise signal through an omnidirectional speakerin the room under test. The sound source should be played
for a long enough time period to ensure that a balance between injected and absorbed acoustic energy has beenreached. For example the sound reflections should be given
enough time to reach all reflective surfaces in the room. As
a rule of thumb, ensure that the pink noise is played for atleast the time period of the estimated reverberation time
test result. If in doubt, play the Minirator MR-PRO, the Test
Signal CD or or USB Flash Drive as sound source for at least
5 seconds for each cycle. Each time the source signal stops,
the XL2 recognizes this interruption, triggers, measures the
decay time and calculates the reverberation time automatically.
A minimum of three measurement cycles shall be performed.

Test Preparations
The XL2 reads the electronic data sheet of any connected ASD
microphones provided by NTi Audio and switches the 48 V
Phantom power automatically on as follows:• Connect the measurement microphone to the XL2.
• Switch on the XL2 .

 The 48 V Phantom power indication in the upper menu barchanges to ASD. The XL2 is ready for acoustic measurements.
• Position the XL2 at the measurement location using a microphone stand or tripod.
• Select the RT60 function in the measurement menu andtoggle with pageto the run page RUN.
• Prepare the environment for the measurement. For example
mute all sound sources to establish silence.

Test Signal: Impulse
Fire an impulse sound source in the room under test, e.g. use
a starter pistol, starter clap or bursting balloon. The XL2 measures the decay time and calculates the reverberation time automatically.

81

Reverberation Time RT60

Set Level Markers• Select the parameter SET with the rotary wheelpress enter .

and The environmental noise is measured and the grey levelmarkers are set.

82

Get Ready for the Reverberation Time Measurement• Protect the ears against high sound pressure levels, as thetest signals might be very loud.
Setting the pink noise level:• Start the pink noise test signal with the appropriate on/off
time according to the room. Use an initial low level.
• Increase the test signal level until all level markers for theminimum test signal level are passed. Use an equalizer topush individual band levels.
• Switch off the interrupted pink noise signal after you havefinished setting the pink noise level.

Reverberation Time RT60

Start the Measurement• Press start. The status indication switches to ARMED.
• Enable the test signal; e.g., switch on the interrupted pinknoise signal or fire a starter pistol.
• The black bars have to exceed the grey bars completely.

Continue the Measurement
Using pink noise:
The interrupted pink noise test signal continues with the preset on/off time. The XL2 automatically triggers at each cycle.
Complete a minimum of three test cycles to accurately calculate the uncertainty factor. Perform more cycles to increase themeasurement accuracy (= smaller uncertainty factor).
Using an impulse source:
A single impulse at one measurement location is sufficient. No
further measurements are required to increase the statisticalmeasurement accuracy.

Confirmation marks
indicating successful measurements, are displayed above each
band.

83

Reverberation Time RT60

Stop the Measurement and Read Out the Result• Press stop.
• If applicable, switch off the pink noise test signal.
• Select the result page RES with page.

The average reverberation time for each frequency band is displayed in seconds and themeasurement uncertainty in %.

•
•
•
•

Read Out the Individual Cycle Result• If multiple cycles have been recorded, then select CYC withthe rotary wheel , press enterand select the individual
cycle result with the rotary wheel .

Within each cycle, the reverberation time foreach frequency band is displayed in seconds
and the correlation factor in %.

•
•
•
•
•
•
•
•
•
•
•
•

 The reverberation time measurement is completed.
84

Reverberation Time RT60

Measurements with multiple source and microphone positions
Room resonances may be applicable at individual measurement positions. Thus, perform reverberation time measurements at further positions within the room and average all
readings.

Overload Indication
In case the measurement result exceeds the preset measurement range, then limit arrows
indicate this overload condition.
Possible causes for exceeding measurement ranges are• The measured sound pressure level exceeds the pre-set
measurement range -> select the next higher measurement
range or reduce the input signal level as applicable.
• The input level is near the maximum level of the connected
NTi Audio measurement microphone.

Error Indications
Various error indications are displayed for unsuccessful reverberation time measurements. Corrupt cycles can be deleted
individually. These results are then excluded from the averagecalculations.
• LOW LEVL						This is the abbreviation of “low test signal level” during themeasurement. Increase the test signal level until the blacklevel markers exceed the grey level markers in every frequency band. Also, ensure that the level falls below the grey
level markers, otherwise use a reverberation time test signal
with longer on/off times.
• T>18S 						The measured reverberation time exceeds the time limit of
18 seconds. This is commonly caused by either an incorrect
analyzer range setting or environmental noise. In the firstcase, choose another range setting. In the second case, ensure that the environmental noise remains constant during
the measurement, and/or SET the level markers again while
the environmental noise is high.

In case the level cannot be reduced (e.g. using a gun as signal
source) then the overload condition can be skipped by storinga text-file with the filename “RT60allowOVLD.txt” on the XL2
main directory.
85

Polarity

Polarity

Positive/Negative Result Page

Polarity measurement is important in matching the left andright speakers for a good stereo sound image. The polarity
function measures the polarity of cables, single speakers andspeaker cabinets. For testing, use the polarity signal provided
on the Minirator test signal generator, the NTi Audio Test CD or
USB Flash Drive.
The polarity of individual speakers or speaker cabinets mightchange with the frequency. For example, the mid-range speaker polarity may differ from the woofer polarity within the same
speaker cabinet. Therefore, the polarity detailed result page ofthe XL2 displays the measured polarity of the individual octave
bands from 125 Hz to 8 kHz. This allows in-depth verification of
the polarity - frequency relationship.

• Polarity is a simple test within the very complex science of signal phasing. Drivers, speakers and crossovers all cause phase shifts of
the audio signal.
• The polarity of various speakers within thesame cabinet may differ by design!
• Polarity testing is useful for checking the correct wiring of similar speaker systems.

86

4
1
3

2

Polarity

Detailed Result Page

1

5
10

6

Input Selection
Select the signal source as follows:• Select Signal Source with the rotary wheel• Press enter
to select either
Voice
Note
Mic

Use the internal voice note microphone of the
XL2 for polarity measurements. This selection
disables the rear speaker.

XLR
Input

Measure the acoustic polarity with a measurement microphone. Alternatively, measure thepolarity of an electrical signal connected with
an XLR audio cable.

RCA
Input

Measure the polarity of an electrical signal connected with an RCA audio cable.

9
8

7

.

2

Polarity Test Result
Displays either POSITIVE, NEGATIVE or ??? (=undefined).
For further visual indication, the limit button
illuminates
green for POSITIVE and red for NEGATIVE polarity.

3

Level RMS
Measures the absolute level of the input signal. The unit’s
dBu, dBV and V are selectable.

Polarity result for Minirator
connected directly to XL2 Analyzer

87Polarity

4

Balance Indicator
Indication of the audio signal balance between pin 2 and 3
on the XLR input for input signals > -34 dBu.

7

X-AxisSeven octave bands with center frequencies from125 Hz to 8 kHz. SUB displays the polarity of Sub-woofers;
frequency range < 100 Hz.

8

Relative Level Indicator
The grey area shows the measured signal energy within
the individual frequency bands. The bands with the biggest
energy have the most effect on the actual displayed POSITIVE / NEGATIVE polarity result.

Negative Polarity Area
Measurement results area with negative polarity (-). The
black line in the middle of relative level indicator 5 displays
the measured polarity of the individual frequency band. The
dashed line indicates the lower limit of the measurement
result area.

9

Uncertain Polarity Area ???
Polarity results for frequency bands in this area are uncertain. Therefore, the polarity result ??? is displayed.

Polarity Indication

10

Positive Polarity Area
Measurement results area with positive polarity (+). The
black line in the middle of relative level indicator 5 displays
the measured polarity of the individual frequency band. The
dashed line indicates the upper limit of the measurement
result area.

The input signal is balanced.
The signal is unbalanced. The level of pin 2 ishigher than pin 3.
The signal is unbalanced. The level of pin 3 ishigher than pin 2.
5

6

88

+

Polarity of frequency band is positive. The polarity result is in the upper display area; the + area.

-

Polarity of frequency band is negative. The polarity
result is in the lower display area; the - area.

Polarity

Polarity Measurement - Getting Started
For acoustic polarity measurement you can use the internal
voice note microphone, or an external measurement microphone, plugged into the XLR input. The polarity result for left
and right speaker cabinets should match for a good stereo
sound image.
• Feed the speaker cabinet with the polarity test signal of the
Minirator.
• Adjust the test level (at Minirator or amplifier) until the test
signal is clearly heard.
• Enable the polarity test signal at the left speaker cabinet;
mute the right speaker cabinet.
• To activate the internal microphone, select Signal Sourcewith the rotary wheel
and choose Voice Note Mic withenter .
• Measure the polarity of the left speaker cabinet and save thescreenshot in the memory menu.
• Enable the polarity test signal at the right speaker cabinet;
mute the left speaker cabinet.
• Measure the polarity of the right speaker cabinet.
• Compare the polarity test result of both speaker cabinets.

 The polarity measurement is completed.

The sample result shows the polarity as:• Sub-woofer:
Low energy, no sub installed• Woofer:
Positive• Mid-range:
Negative• Tweeter:
Positive (with small levels)
The major part of the signal energy is measured
in the mid-range frequency bands. Therefore,
the overall displayed polarity is NEGATIVE.

89

Delay Time

Delay Time1

The delay time measurement function is suitable for accurate
configuration of delay line setups, by optimizing the directionality of the signal source. The XL2 measures the delay time
between the reference signal and the acoustic signal from the
speaker. The acoustic delay settings are displayed, allowing you
to easily set the measured delay time into the delay device inthe rack. The NTi Audio delay time test signal is provided either
by the Minirator MR-PRO, MR2 or the NTi Audio Test CD / USB
Flash Drive included with the XL2.

1

2
3

4
5

90

7

2

6
3

Delay Signal Source
Select the signal source for the delay measurement:
CD Player

Using the NTi Audio Test CD; this setting implies the synchronization time bar
is set to 100 seconds = 1 min. 40 sec.;
after 100 seconds the XL2 has to be synchronized to the delay test signal again.

Minirator

The Minirator MR-PRO and MR2 provides
a more reliable test signal source than a
CD player. Therefore, the XL2 offers an extended time range without synchronization.
Only after 300 seconds (5 minutes) does
the XL2 have to be synchronized to the delay test signal again.

Store Button
Press the store button to record the actual delay
reference speaker.

7

Reference Delay Time
Individually-stored delay time of reference speaker.

of theDelay Time4

Calculated Distance
Distance from measurement position to speaker in metersor feet, based on the defined temperature in °C or °F

5Synchronization Time Bar
The automated synchronization allows delay time measurements without any connected electrical reference
signal for 100 seconds using the NTi Audio Test CD / USB
Flash Drive or 300 seconds using the Minirator, MR2 or
MR-PRO. It displays the time remaining until the next required synchronization.

6

Calculated Delay Time: Store - Actual
Calculated difference between delay time of speaker A andspeaker B as shown on the next page. The automated difference calculation simplifies the verification of delay line
arrangements, such as those used in larger halls or auditoriums.

7

Actual Delay
Actual measured delay time referring to the electrical reference signal.

Delay Test utilizes VoiceNote Microphone
The XL2 uses the internal VoiceNote microphone to measure the acoustic delay. Do notconnect any measurement microphone to the
XL2 for the delay time measurement.

Rear Speaker
The rear speaker on the XL2 is disabled during
delay measurements, thereby avoiding measurement failures. The headphone output is active.

91Delay Time

Delay Measurement - Getting Started
The delay time measurement is conducted between the synchronized electrical input signal and the acoustic signal measured by the built-in voice note microphone. In this example,
the delay between speakers A and B in the illustrated auditorium is measured.
speaker
front rightspeaker A
front left
lecturer

speaker B
sub leftmeasurement
position92

speaker
sub right

Test Preparations• Prepare the delay test signal; use either the• NTi Audio Test CD or USB Flash Drive• NTi Audio Minirator for analog systems• NTi Audio Digirator for digital or Dolby/DTS systems• Start the delay test signal.
• Connect the generated delay test signal with an audio cableto the RCA or XLR input of the XL2, e.g. take the reference
signal from an auxiliary channel of a mixing console.
• Select XLR or RCA input in the upper XL2 menu
• Set the actual environment temperature, to ensure that the
distance is displayed correctly later.

Delay Time• Wait until the XL2 synchronizes to the incoming delay test
signal, then the synchronization time bar fills up.

• Disconnect the audio cable, with the synchronizing signal,
from the XL2, allowing you to move around freely for thedelay measurement. When selecting Minirator as the delay
signal source, the XL2 has to be synchronized to the signal
source again after 5 minutes. When selecting CD Player as
the delay signal source, the XL2 has to be synchronized tothe signal source every 100 seconds.

Measure Reference Speaker A• Start the delay test signal at speaker A, mute speaker B.
• Position yourself with the XL2 at the measurement position
next to speaker B sub left as indicated above. This is theworst-case position in the auditorium with regard to acoustic
delay in the sound field. The XL2 uses the VoiceNote microphone for the delay test; do not connect any measurement
microphone.

 The XL2 measures the delay time of speaker A in reference
to the electrical input signal in milliseconds.
93Delay TimeStore Reference• Select the displayed 0.0 ms below Act. Delay with the rotarywheel
and press enter .

 The reference result of speaker A is stored for the differ-

Measure Sub Speaker B• Start the delay test signal at speaker B. Mute speaker A.
• Position yourself with the XL2 at the shown measurement
position. The XL2 uses the VoiceNote microphone for the delay test; do not connect any measurement microphone.

ence calculation of delay A - B.
• Stop the delay test signal at speaker A.

 The XL2 measures the delay time of speaker B in reference
to the electrical input signal in milliseconds.

94

Delay Time

Automated Difference Calculation• The delay time difference between speaker A and B is
automatically calculated and shown below the Act. Delay
result.

 The delay time is measured.

Delay Test utilizes VoiceNote Microphone
The XL2 uses the internal VoiceNote microphone to measure the acoustic delay. Do notconnect any measurement microphone to the
XL2 for the delay time measurement.
Measurement Position
Do not position the XL2 too close to reflecting
surfaces, such as walls or floors. The reflections
are likely to prevent accurate measurements.

Result Interpretation• The resulting time in milliseconds shows
the time difference of the sound signal fromspeaker A and B arriving at the measurement
position. Speaker B has to be delayed by thedisplayed difference result.
• To optimize directionality, add a further 5 ms
to the calculated difference. The main signal
from speaker A then arrives at the measurement position first. The acoustic signal fromsub speaker B arrives 5 ms later. This improves the subjective directionality perception of the listeners.
Distance in meter/feet
The distance results in meter/feet are displayed
below for easy verification of the test results
accuracy. The readings are based on 330 m/s
sound speed at 0°C / 32°F.

951/12 Octave + Tolerance

1/12 Octave + Tolerance (optional)
The Spectral Limits Option extends the XL2 function range
with an RTA analyzer with spectral resolutions from 1/1 octave
down to 1/12th octave. Trace capturing, relative curve display
and comprehensive tolerance handling are supported in the
FFT Analysis and the high-resolution 1/12 Oct + Tol spectral
analysis.
Features• High-resolution RTA function “1/12 Oct + Tol” with selectable 1/1, 1/3, 1/6 and 1/12 octave spectral resolution• Capturing of multiple readings into the internal memory• Comparing measurement results against captures with relative or absolute curve display• Comprehensive tolerance handling with tolerance masks
based on captures for passed/failed measurements• Export and import of tolerance and capture files• Frequency band listening at rear speaker96

Applications• PA-rental: Verifying the frequency response of returned
speakers and microphones against reference records ensuring they are back in stock in good working condition.
• Industrial quality testing: Passed/Failed test in the production
line or during service of any audible quality criteria, such aswith motors, machines, vacuum cleaners, ...
• Cinema: Comparing frequency responses against an ideal
response curve according the X-Curve requirements.
Tolerance Handling
The XL2 Analyzer compares spectral measurements against atolerance band and visualizes exceptions in every frequency
band. The passed/failed condition is further visualized by thelimit button
and forwarded to the I/O interface of the instrument in order to drive an external alarm device such the accessory SPL Stack Light.
Tolerance curves can either be imported from txt-files or directly derived from captured measurements. The XL2 calculates
tolerance bands based on• Single captured results• Manually generated txt-files on the PC• Mean average of multiple captures• Min/Max curves of multiple captures

1/12 Octave + Tolerance

1

14

Result Symbols / Capture & Start Tolerance Mode
This field offers two functions:• Symbols for measurement results 2

13Upper parameter displayed as line.
12

1

Lower parameter displayed as bargraph.

11

2

3
10
4

9

• Capture & Start Tolerance Mode
The displayed spectral readings may be captured in C1- C8 for• Comparing measurement results against captureswith relative or absolute curve display.
• Creating tolerance masks based on captures forpassed / failed measurements.

8
5

6

7

Capture EQ

Captures the upper parameter

Capture Live

Captures the lower parameter

Managecaptures

Allows to rename captures, clear recorded captures, save captures to the SD
Card for export or load captures from the
SD Card for import to the XL2.
97

1/12 Octave + Tolerance

Start tolerance Starts the tolerance mode for passed/mode
failed measurements comparing theactual measurement results against atolerance band.
2

5

Measurement Result
Actual level result of the indicated frequency band. The cursor readout displays the center frequency and the level ofthe band indicated by the arrow.
Upper parameter displayed as line.

Select the lowest possible input range according to the
maximum level expected during the measurement; e.g., if
the sound pressure will be always below 110 dBSPL, thenselect the lowest input range 10 - 110 dBSPL.

Lower parameter displayed as bargraph.
3

4

98

Y-Scale setting• Select the Y-Axis with the rotary wheel
and confirm
with enter .
• Select the zoom factor between 20, 10, 5, 2.5 dB/div
and confirm with enter .
• Scroll up and down with the rotary wheel
to select the
Y-axis range.
• Confirm with enter .
Spectral Measurement Result
Spectral results in 1/1, 1/3, 1/6 or 1/12 octave band resolution. Adjust the resolution at 12 .

Input Range
The XL2 Analyzer provides three input ranges to accommodate the wide range of input signals. The individual ranges are based on the microphone sensitivity setting in thecalibration menu of the XL2. For example at a sensitivity
S=20mV/Pa the input ranges are• Lower range: 10 - 110 dBSPL• Middle range: 30 - 130 dBSPL• Upper range: 50 - 150 dBSPL

6Time Weighting
Offers selectable time weighting of 0.1, 0.2, 0.5, 1.0 second
as well FAST (125 ms) and SLOW (1 second). Applications:Short Time
WeightingHigh-resolution in time with minimum
averaging

Long Time
Weighting

Low resolution in time with longer averaging

1/12 Octave + Tolerance

7

8

Run Indication
The run indication shows the measurement status running,paused or stopped. Various measurement settings arelocked during ongoing measurements, such as changing
the input ranging or the preset measurement time.
For passed/failed measurements with the Spectral Limits
option the run indication may display A for a preset automated level trigger.
Actual Measurement TimeCounts actual measurement time in hrs:min:sec. Supports
setting of time modes: continuous and single.
Timer Mode Continuous(applicable for standard measurements)
All values are recorded and monitored continuously after starting a measurement with start.
The actual measurement time is shown.

9

Preset Measurement Time
Adjustment of preset measurement time for single timer
setting.

10 Broadband Results

User-selectable display of broadband results:
Broadband A

A-weighted level

Broadband C

C-weighted level

Broadband Z

without any frequency weighting

-

none

Sum ofbands

Sum of displayed frequency bands (onlyavailable when #HideUnusedBands is
set to True within the tolerance file)

Timer Mode Single
Automatically stops the measurement after the
pre-set measurement time.
• Set the required measurement time.
• Start the measurement.

991/12 Octave + Tolerance

11

Readout Frequency
You may select any frequency to read out individual levels.
The selected frequency is indicated by the cursor arrow.
Choose between the following settings:
The cursor automatically follows the highest level,
e.g. tracing live performance feedback frequencies• Select the frequency with the rotary wheel .
• Press enter .
• You may read out any individual frequency.
• Return to auto frequency with enter .

12 Setting of Test Result Resolution

Set the spectral result display to 1/1, 1/3, 1/6 or 1/12 octave
band resolution as follows:• Turn the rotary wheel
to select the parameter 12 .
• Press enter
to open the selection window.
• Turn the rotary wheel
to select 1/1 OCT, 1/3 OCT,
1/6 OCT or 1/12 OCT• Press enterto confirm.
13 Phantom Power Supply

48V

The XL2 provides 48 V Phantom power supply to the microphone or sensor.

ASD

An NTi Audio measurement microphone with
automated sensor detection ASD is connected. The XL2 reads the electronic data sheet ofthe microphone and switches the 48 V Phantom power automatically on.

48V

Phantom power is switched off.

 The cursor returns to the frequency with highest level bar.
The cursor readout may be set manually to any
frequency band or wideband level. The readout remains at the selected frequency.
• Select the frequency with the rotary wheel .
• Press enter .
• Select the frequency of interest.
• Confirm with enter .

 The cursor readout 2 displays the measurement results of the selected frequency band.
100

1/12 Octave + Tolerance

14 Measurement Unit

Select the measurement unit as follows:dB

Sound level in dBSPLThis measurement unit is permanently selected
while an NTi Audio measurement microphonewith electronic data sheet is connected.

Band Listening
The selected frequency band of the input signal
is audible on the rear speaker or at the headphone output.

dBu

Input level in dBu• Press and hold the speaker button
down.
The pop-up window Volume is displayed.
• Keep the speaker buttonpressed andpress enterat the same time.

dBV

Input level in dBV

 The band listening is activated.

V

Input level in Volt101

1/12 Octave + Tolerance

1/12 Octave - Getting Started
Test Preparations
The XL2 reads the electronic data sheet of any connected ASD
microphones provided by NTi Audio and switches the 48 V
Phantom power on automatically as follows:• Connect the measurement microphone to the XL2.
• Switch on the XL2 .

Configuration
The XL2 displays two different sound pressure levels at thesame time. You configure to display either the levels Live,
Max, Min, EQ, EQ1“, EQ4“ or captured results.
• Select the upper result parameter with the rotary wheel

 The 48 V Phantom power indication in the upper menu barchanges to ASD. The XL2 is ready for acoustic measurements.
• Position the XL2 at the measurement location using a microphone stand or tripod.
• Select the 1/12 Oct + Tol function in the measurement
menu.

The displayed wideband and spectral levels aremeasured and stored simultaneously.

• Confirm with enter

102

.

.

1/12 Octave + Tolerance

Select Upper/Lower Reading The pop-up window Select reading appears.

 The pop-up window Select reading mode appears.

• Select the time-averaged sound level EQ. All available selections are Z-weighted (= no weighting).

• Select EQ for normal absolute display of measurements.
• Follow the same instruction and select the lower spectral
reading Live.
• Confirm with enter.
Press start
to measure and display thesound levels results indicated with ----.

103

1/12 Octave + Tolerance

Select Input Range
Select the lowest possible input range according to the maximum level expected during the measurement.
• Select the input range RNGE and press enter .
• Turn the rotary wheel to set the applicable input range andconfirm with enter .

Start Measurement• The XL2 measures the selected sound pressure levels Live and EQ. All available sound levels are
Z-weighted (= no weighting).
• Press start.

 The run indication switches to running. The actual soundlevel Live and the averaged level EQ are displayed. The parameter RUN flashes in the memory menu.

1041/12 Octave + Tolerance

Stop Measurement and Data Saving• Press stop.

 The XL2 stores the measurement data automatically.

Audio Recording
The XL2 Analyzer may record a linear audio file (48 kHz, 24 Bit)of the measurement period together with the spectral data. Justload a txt-file named “12audio.txt” in the root directory of the
XL2. This requires the installed option Extend Acoustic Pack.
Capture References and Create Tolerances
The Spectral Limits Option extends the function range of the
XL2 with trace capturing, relative curve display and comprehensive tolerance handling for the FFT Analysis and the highresolution 1/12 Oct + Tol spectral analysis.

• Press enterto confirm. The measurement data is stored
on the SD Card in ASCII format.

 The measurement is completed.

Features:• Capturing of multiple readings into the internal memory• Comparing measurement results against captures with relative or absolute curve display• Comprehensive tolerance handling• Creating tolerance masks based on captures for passed /failed measurements• Export and import of tolerance and capture files• True peak level in 1/1 and 1/3 octave resolution• High-resolution Zoom-FFT up to 0.4 Hz steps in the frequency range 5 Hz - 20 kHz
Read the detailed description in the separate chapter
Spectral Limits Option (Capture + Tolerances).
105

1/12 Octave + Tolerance

1/12 Octave - Fast Frequency Response
Measurement
The XL2 provides fast and accurate frequency response measurement within one second using pink noise. For this purpose, the Minirator MR-PRO generates the test signal “FastPink Noise” tailored to this application.
Test Signal
The test signal “Fast Pink Noise” is not “random”; it contains
an absolutely flat spectrum within the cycle time. The frequency resolution of the test signal is limited to 1 / cycle time; therefore you can choose between two different test signals:

Minirator MR-PRO
Test Signal

XL2 Frequency
Resolution

XL2
Measurement
Duration

File -> Signals ->Fastpnk1

1/1 Octave
1/3 Octave

1 second

File -> Signals ->Fastpnk4

1/6 Octave
1/12 Octave

4 seconds

106

Measurement in 1/3 Octave Resolution• Select the test signal Fastpnk1 on the Minirator MR-PRO.
• Connect the MR-PRO to the input of the device under test.
• Take the XL2 and select the function 1/12Oct.
• Select the one-third octave band frequency resolution.
• Select the measurement parameter EQ, the mode “Single”
and set the measurement duration to one second.
• For higher frequency resolutions use the test signal Fastpnk4 and a measurement duration of four seconds.
• Start the measurement.

 You have successfully completed the measurement.

1/12 Octave + Tolerance

Optimize the Frequency Response
The fast frequency response measurement with the test signal “Fast Pink Noise” saves time in optimizing the frequency
response of audio devices or speakers. During your settings
on the equalizer, you will receive a precise result on the XL2screen within one second.

Test Signal „Fast Pink Noise“ Advantage
Frequency response measurements often use
the standard Pink Noise in combination witha 1/n octave analysis. Because of the randomness, longer averaging times are necessary to
get accurate results. Too short averaging times
result in “noise” in the result, as shown here:• Select the test signal Fastpnk1 on the Minirator MR-PRO.
• Connect the MR-PRO to the input of the device under test.
• Take the XL2 and select the function 1/12Oct.
• Select the measurement parameter EQ1”, the mode “Single” and set the measurement duration to one second.
• Adjust the settings on the equalizer.

 The XL2 displays the actual frequency response within asecond.

In comparison, the test signal “Fast Pink Noise”
enables a precise measurement result within
one or four seconds.

107Noise Curves

Noise Curves (optional)
The Spectral Limits Option extends the XL2 with the Noise
Curves measurement function. A noise curve may be used tocharacterize room noise or other environments. Various standardized international noise curves are the most widely usedmeans for evaluating background sound in buildings, and otherfacilities such as transit facilities, as well as in other indoor/
outdoor spaces. Residual noise in buildings may be generated
from both environmental sources (e.g. outside traffic) and systemic sources (e.g. heating, ventilating, and air-conditioning(HVAC) systems; or other machinery in use). It is also frequently
necessary to measure residual noise curves prior to expectedchanges in advance of construction or prior to other expectedenvironmental noise changes.

Noise Rating NR(in accordance with ISO/R 1996-1971)
Noise rating (NR) is a graphical method for assigning a single
number rating to a noise spectrum. It can be used to specify
the maximum acceptable level in each octave band of a frequency spectrum, or to assess the acceptability of a noise
spectrum for a particular application. The method was originallyproposed for use in assessing environmental noise, but it is108

now used frequently for describing noise from mechanical ventilation systems in buildings. To make a rating, the measured
noise spectrum is superimposed on a family of NR contours;
the NR of the spectrum corresponds to the value of the first
NR contour that is entirely above the spectrum.

Noise Criteria NC(in accordance with ANSI S12.2-2019 and -1995)
The NC rating of a spectrum is designated as the value of thelowest NC curve above the measured octave-band spectrum.
The designating number for any NC curve is, approximately,
its Speech Interference Level (SIL): the average of the levelsin the 500, 1000, 2000 and 4000 Hz octave bands. SIL is a
simple metric, which measures the effects of noise on speech
intelligibility. The XL2 Analyzer includes the tangency method
adaptation in accordance with the standard.

Room Noise Criteria RNC(in accordance with ANSI S12.2-2019)
The RNC method is used to determine noise ratings when thenoise from HVAC systems at low frequencies is high, and whichis also suspected of containing sizeable fluctuations or surging.

Noise Curves

It essentially represents a rumble criterion. The RNC curves
also provide a procedure that reduces the result essentiallyback to the NC curves when systems are well designed andacoustically well-behaved. Following the RNC specification, theXL2 measures the octave-band sound pressure level every 100
ms, followed by processing to determine the applicable roomnoise criterion (RNC) curve. The minimum measurement timeis 20 seconds.

Preferred Noise Criteria PNC(in accordance with ASA 1971)
PNC curves represent a more stringent method based on an
extension of the basic Noise Criteria system. They have beenused in the past to judge the acceptability of ventilation andother background broadband noise. PNC curves are less often
used than Noise Criteria curves because they are more stringent at lower frequencies than the Noise Criteria curves, butalso because the latest (2019) version of Noise Criteria curves
also includes an extended frequency range somewhat mitigating the original reasons for PNC.

Room Criteria RC(in accordance with ANSI S12.2-1995)
The RC criterion curves are a system for use in the designof heating, ventilating, and air-conditioning (HVAC) systems in
office buildings, dwelling units, etc., where the desired midfrequency levels are in the range of 25 to 50 dB. Each RC criterion curve bears a rating number equal to the level at 1000 Hz.
Spectrum classification• Neutral spectrum (N): The levels at 500 Hz and below do not
exceed the RC curve corresponding to a sound level spectrum by more than 5 dB; and the spectrum levels in Band
1000 Hz and higher do not exceed the corresponding RC
curve by more than 3 dB.
• Rumble (R): Excessive noise in low-frequency band
The level in one or more of the octave bands at and below
500 Hz exceeds the RC curve corresponding to a spectrum
by more than 5 dB.
• Hiss (H): Excessive noise in high-frequency bands
The level in one or more of the octave bands at and above
1000 Hz exceeds the RC curve corresponding to a spectrum
by more than 3 dB.
• Vibration and rattle (RV): The level in one or more of the octave bands from 16 Hz through 63 Hz exceeds the criterion
for moderately noticeable rattle.
109

Noise Curves

Noise Curves Result Page

RNC Information Page

1

12

2

11

13

3

4
5

14

6
10
9
7

8

The standards list the noise criteria in 5 dB steps. The XL2
measures the noise criteria in detailed 1 dB steps, which arecalculated by linear interpolation between the standardized
5 dB levels.

110

The RNC information page is available when viewing Noise Criteria and Room Noise Criteria results, in accordance with ANSI
S12.2-2019. It reports any large fluctuations or surging at low
frequencies, e.g. caused by fans.

Noise Curves

1

Noise Curve
Selection of the noise curve type and measurement result.
Noise Curve Types• Noise Rating NR• Noise Criteria NC (2019) and (1995)• Room Noise Criteria RNC• Room Criteria RC (1995)• Preferred Noise Criteria PNC (1971)
Measurement Result
The noise rating of a spectrum is designated as the value ofthe highest curve “touched” by the measured octave-band
spectrum. The octave band in which this “touching” occurs
is noted along with the curve designation.

2

Measurement Result
Actual level result of the indicated frequency band. The cursor readout displays the center frequency and the level ofthe band pointed to by the arrow. With the cursor in automatic mode, the arrow points to the frequency band withthe highest noise rating as shown in 1 .

3

Y-Scale setting• Auto-Scroll• Zoom:- Select the Y-Axis with the rotary wheel
and confirm
with enter .
- Select the zoom factor between 10, 5, 2.5 dB/div andconfirm with enter .

4

Noise Measurement Result
Real-time spectrum in 1/1 octave band resolution.

5

Noise Floor
The grey area shows the noise floor of the connected NTi
Audio measurement microphone (provided by the electronic data sheet) in combination with the XL2 Analyzer.

6

X-ScaleX-Scale from 16 Hz to 8 kHz.

111

Noise Curves

7Live View
Select the LiveView with the rotary wheel
to get an
overview of the current noise level. Alternatively press thelimit button .
The XL2 measures the noise curve after pressing the start
button. This will provide the noise rating measurementin accordance with all standards.

8

Run Indication
The run indication shows the measurement status running,paused or stopped. Various measurement settings arelocked during ongoing measurements, such as the presetmeasurement time.

9

Actual Measurement TimeCounts actual measurement time in hrs:min:sec. Supports
time modes: continuous and single.
Timer Mode Continuous(applicable for standard measurements)
All values are recorded and monitored continuously after starting a measurement with start.
The actual measurement time is shown.
Timer Mode Single
Automatically stops the measurement after the
pre-set measurement time.
• Set the required measurement time.
• Start the measurement.

 The actual measurement time counts back tozero and the measurement ends.

10 Preset Measurement Time

Adjustment of preset measurement time for the timer
mode single.

112

Noise Curves

11

Readout Frequency
You may select any frequency to read out individual levels.
The selected frequency is indicated by the cursor arrow.
Choose between the following settings:
The cursor follows automatically the frequency
band with the highest noise rating.
• Select the frequency with the rotary wheel .
• Press enter .
• You may read out any individual frequency.
• Return to auto frequency with enter .

 The cursor returns to the frequency with highest noise rating.
The cursor readout may be set manually to any
frequency band or wide band level. The readout remains at the selected frequency.
• Select the frequency with the rotary wheel .
• Press enter .
• Select the frequency of interest.
• Confirm with enter .

 The cursor readout 2 displays the measure-

12 SIL Measurement Result

The speech interference level (SIL) result is shown fornoise curve types NC-2019 and NC-1995 1 . It is calculated by averaging the octave-band sound pressure levels
at 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz. If the measured
spectrum in any octave band does not exceed any of theoctave bands of that NC(SIL) curve, the spectrum is designated NC(SIL). If one or more octave-band levels exceed
the NC(SIL) curve, then the NC curve number may differ tothe SIL value, as the NC rating for that spectrum must be
determined using the tangency method.
13 Large Fluctuations

This reports any large fluctuations at low frequencies
for the Room Noise Criteria RNC in accordance withANSI S12.2-2019. If one or more displayed measurement
results exceed the limits, then large fluctuations exist.
Concluding the LEQ levels in the octave frequency bands
below 300 Hz are automatically “penalized” at the RNC
measurement.
14 Correction Values

The noise curve type RNC uses these correction values
based on the measured fluctuation results to determine
the RNC curve result.

ment results of the selected frequency band.
113

Noise Curves

Recommendations
NC and
RNC
Curve

Level
LAeq

RC curve

Type of Room Space TypeNC and
RNC
Curve

Level
LAeq

RC curve

Concert and recital
halls

-

15-18

-

Family rooms and living
rooms

39-48

30-40

30-35 (N)

Small auditoriums(≤500 seats)

35-39

25-30

-

Hotels/Motels
30-35

25-35 (N)

30-35

20-25

-

Individual rooms orsuites39-44

Large auditoriums(>500 seats)

25-35

25-35 (N)

16-35

15-25

-

Meeting/banquet
rooms

35-44

TV and broadcast studios

Service support areas

48-57

40-50

35-45 (N)Live performance theaters

25-30

20-25

-

Premier movie theaters

25-30

20-25

-

Offices executive

35-44

25-35

25-35 (N)Normal theater

30

25

-

Offices small

44-48

35-40

25-35 (N)Offices large

39-44

30-35

-

Conference rooms
large

35-39

25-30

25-35 (N)

Conference rooms
small

39-44

30-35

25-35 (N)Type of Room Space TypePrivate residences
Bedrooms

35-39

25-30

25-30(N)Apartments

39-48

30-40

30-35 (N)114

Office buildings

Noise Curves

Noise Curves - Getting Started

Configuration• Select the noise curve type with the rotary wheel.

Test Preparations
The XL2 reads the electronic data sheet of any connected ASD
microphones provided by NTi Audio and switches the 48 V
Phantom power automatically on as follows:• Connect the measurement microphone to the XL2.
• Switch on the XL2 .

 The 48V Phantom power indication in the upper menu barchanges to ASD. The XL2 is ready for acoustic measurements.
• Select the Noise Curves function in the measurement
menu.

The microphone should be moved slowly to positions around the entire space at locations thatare near the average normal standing or seatedheight of human ears. The recommended measurement period is more than 20 seconds long.

• Confirm with enter.

The XL2 measures all noise curve types at thesame time, thus you can change the selection
also after the measurement.

115

Noise Curves

Start Measurement• Press start.

Stop Measurement and Data Saving• Press stop.

 The run indication switches to running The XL2 stores the measurement data automatically.

. The actual noiselevel LZeq of the selected octave band is displayed. The
parameter RUN flashes in the memory menu. The Y-axis
adjusts automatically according the measurement result.

• Press enterto confirm. The measurement data is stored
on the SD Card in ASCII format.

 The measurement is completed.
116

Noise Curves

117

STIPA

Speech Intelligibility STIPA (optional)
The STIPA analyzer option allows reliable measurementof the speech transmission index (STI) within 15 seconds.
Besides the single value STI or CIS (= common intelligibility scale) test result, a detailed view of the modulation indices and individual band level results is provided. The STIPA analyzer meets the standard IEC 60268-16, edition 5
released in 2020. The XL2 also supports noise corrections, automated averaging of measurements and the older standard
editions 2, 3 and 4.
The intelligibility of speech depends on:• Signal-to-noise ratio• Psychoacoustic masking effects• Sound pressure level• Ambient noise level• Reverberation time
• Reflections• Frequency response• Distortion
The speech intelligibility measurement function STIPA is an option for the XL2 Audio and Acoustic Analyzer. Ask your local
representative for purchasing details.

118

Signal Source
Choose the applicable STIPA test signal source:
NTi Audio
TalkBox

The NTi Audio TalkBox simulates a person talking
at a precise acoustic level, enabling the measurement of the complete signal chain including the
microphone.
• Place the NTi Audio TalkBox in front of the microphone at the typical position of the talking
persons head.
• Select Track 1 for the STIPA test signal.
• Select Output Mode to Speaker; you shouldhear the STIPA test signal.

Minirator
MR-PRO

The Minirator MR-PRO is used for electrical signal
injection into public address systems that commonly use alarm messages from a hard drive(systems without a microphone).

Other Audio Register the XL2 and download the STIPA test
Playersignal at https://my.nti-audio.com/support/xl2.
The maximum tolerable deviation in test signal
playback sample frequency is 0.1%.
The standard STIPA signal is based on random noise limited tothe bands contained in a male speech spectrum.

STIPASTIPA Numeric Result Page

STIPA Table Result Page

10

1

9
8

2

7

3
4
5

6

11

12

13

14

Use only the original NTi Audio test signal for
speech intelligibility measurements with the
XL2. Other signals may not seamlessly loop,
thus causing wrong measurement results!

119

STIPASTIPA Averaging

STIPA Ambient Noise Correction

24

18

23
15
19

16

21

17

20

1

120

22

Run Indication
This icon displays the run status of the measurement.

STIPA2

3

4

5

Measurement Result• Single value speech transmission index result.
• Repeatability of measurement result:
Since a dedicated noise test signal is used, the result
may deviate by a of maximum 0.03 STI (=Max-Min) at thesame measurement position.
Sound Level LAeq
Shows the time-averaged sound level of the 15 seconds
measurement cycle time.
Sound Level LAS
Actual sound pressure level.
Analog Test Result Bargraph
Bargraph display and interpretation of the speech intelligibility measurement result• Exlnt		
0.75 - 1.00 STI• Good		0.60 - 0.75 STI• Fair		0.45 - 0.60 STI• Poor		0.30 - 0.45 STI• Bad		0.00 - 0.30 STI

6

Qualification Scale
The STI value is shown as a letter representing the qualification scale below. Listed are also examples of typical application environments.
Band

STI Range

Examples of typical usesA+

> 0.76

recording studios

A

0.72 - 0.76

theatres, speech auditoria,
parliaments, courts

B

0.68 - 0.72

theatres, speech auditoria,
parliaments, courtsC

0.64 - 0.68

teleconference, theatresD

0.60 - 0.64

class rooms, concert halls

E0.56 - 0.60

concert halls, modern churchesF

0.52 - 0.56

PA in shopping malls,
public offices, cathedrals

G

0.48 - 0.52

PA in shopping malls,
public offices

H

0.44 - 0.48

PA in difficult acoustic
environments

I

0.40 - 0.44

PA in very difficult spaces

J

0.36 - 0.40

not suitable for PA systems

U< 0.36not suitable for PA systems

121

STIPA

7

Measurement Unit
The speech intelligibility result is displayed in STI (Speech
Transmission Index) or CIS (Common Intelligibility Scale),whereby CIS is calculated as CIS = 1 + log STI.

9

8

Edition of Standard IEC60268-16

10 Page Selector

ed5.0

actual edition released in 2020 with continuous
level dependent auditory masking function

ed4.0

old edition released in 2011 with continuous
level dependent auditory masking function

ed3.0

old edition released in 2003 with stepped level
dependent auditory masking function

ed2.0

old edition released in 1998 with fixed masking
function

Progress Bar
Measurement status indication; a single speech intelligibility measurement takes 15 seconds. The actual measurement time and measurement status are indicated here.

Select between these pages:
Speech intelligibility measurement result
Table result page with modulation ratio andsound levels for each octave bandOn-site averaging of results.
Ambient Noise Correction
The page button
toggles between the 123 - Tab - Avr
screens. These pages show the speech intelligibility measurement results. The page Cor offers setting the noise
spectra prior the STI measurement.
11

Octave Bands
Frequencies 125 Hz - 8 kHz in 1/1 octave band resolution.

12 Sound Pressure Level L

eq
Individual time-averaged octave band level Leq.

122

STIPA

13 STIPA Modulation Ratio mr1, mr2

14 Error Detection

For good speech intelligibility it is mandatory that the integrity of the transmitted voice signal modulations are preserved. Therefore, STIPA is based on measuring the MTF(Modulation Transfer Function). This function quantifies thedegree to which the voice modulations are preserved inindividual octave bands. The STIPA method determines the
MTF by analyzing the seven frequency bands. Each band ismodulated with two frequencies, resulting in the modulation ratio mr1 and mr2. All indexes together combined withpsycho-acoustic models provide the single-value speech
intelligibility result.

The built in error detection helps identifying faulty measurements caused by the amount of impulsive ambient noise.
Such noise influences the accuracy of any speech intelligibility measurement. The error detection checks the following:• Invalid modulation indices in individual octave bands (mr1or mr2 > 1.3)
• Changes in ambient noise or any impulsive noise during the measurement (by comparing the first half of themeasurement period with the second half)
15 Cycle Reading

Band

mr1

mr2

125 Hz1.60 Hz8.00 Hz250 Hz1.00 Hz5.00 Hz

500 Hz0.63 Hz3.15 Hz

1 kHz

2.00 Hz10.00 Hz

2 kHz

1.25 Hz6.30 Hz

4 kHz

0.80 Hz4.00 Hz

8 kHz

2.50 Hz12.50 HzThe standard IEC 60268-16 recommends measuring the
speech intelligibility two or three times at each measurement position. This reduces potential measurement errors.
The individual cycle readings are listed here.

16 STI-Average

Calculated average of the recorded cycle results.
17 Difference

Difference (Max – Min) of the of the recorded cycle results.

123

STIPA

18 Start next Cycle Measurement

Start the next cycle measurement at the same measurement position here.

22 Spectral Level of Ambient Noise

Adjustable octave band level from 125 Hz to 8 kHz. The default spectrum is equals the replayed STIPA test signal at
LAeq = 80 dB.

19 Ambient Noise Measure / Load / Save

Measure here the actual ambient noise during an adjustable measurement time. You may save this record and reload the data set for any later speech intelligibility measurement.

23 Activation of manual Octave Band Level Setting

Select EDIT with the rotary wheel
vidual octave band levels.

to adjust the indi-

24 Activation of Ambient Noise Correction
20 Source of Data

Informs about the source of the ambient noise data. The
choices are:• Default Settings• Edited manually• Measured Date Time
This information is documented in the measurement report.
21 LAeq of Ambient Noise

This LAeq is calculated based on the octave band levels;
you may manually set this level in accordance with the typical noise level as specified for your application. The default
level is 80 dB.

124

On

Ambient noise correction is active

Off

Ambient noise correction is deactivated

The XL2 Analyzer has been manufactured incompliance with all specifications as describedin IEC 60268-16. Due diligence has been observed in validating• the measuring system• the accuracy of the measured STI across a
range of relevant reference conditions• the accuracy of the modulation transfer function matrix.

STIPA

Question Mark ? at individual Octave Bands
Individual octave bands are marked with ? in case of a
• Missing test signal level• Invalid modulation indices (mr1 or mr2 > 1.3)
• Changes in ambient noise or any impulsive noise during themeasurement
Flashing Question Marks ?.?? at 2
The measurement result flashes in combination with the question marks ??? in case of a
• Question Mark ? at one or multiple octave bands. See the
STIPA Table Result Page on the XL2 for details.
• Changes in ambient noise or any impulsive noise during themeasurement

In case the question marks ?.?? are flashing,then the measurement is faulty. Verify possible
causes and repeat the measurement.
For details see the chapter STI Measurement
Hints.

STI Measurement - Getting Started
Test Preparations
The XL2 reads the electronic data sheet of the connected
NTi Audio measurement microphone and switches the 48 V
Phantom power automatically on as follows:• Connect the measurement microphone to the XL2.
• Switch on the XL2 .

 The 48 V Phantom power indication in the upper menu barchanges to ASD. The XL2 is ready for acoustic measurements.
• Position the XL2 at the measurement location using a microphone stand or tripod.
• Select the STIPA measurement function in the measurement menu.
• Prepare the environment for the measurement. For example
mute all sound sources to establish silence.

No impulsive noise shall occur during the
speech intelligibility measurement as well no
speaking or other noise sources should be allowed near the measurement microphone.
125

STIPA

Start STIPA Test Signal
Select the STIPA signal source according your application requirements.
• Switch on the STIPA test signal at the signal source.
• Set the acoustic sound pressure level of the PA system tosimulate the typical announcement level; e.g. LAS = 85 dB.

126

Start Measurement• Press start.

 The progress bar switches to RUNNING. The test result
tendency is shown on the bargraph, marked with Bad,
Poor, Fair, Good and Exlnt.

STIPA

Stop Measurement and Data Saving
After the period of 15 seconds the speech intelligibility measurement finishes automatically. The progress bar indications
switches to FINISHED and the final test result is displayed. The
measurement result is stored automatically.
• Switch off the STIPA test signal.

Averaging of STI Results
The standard IEC 60268-16 recommends averaging two or
three subsequent results taken at the same measurement location.
The German Standard VDE 0833-4 requires performing minimum three subsequent measurements for one measurement
position in case of STI < 0.63.
The XL2 Analyzer offers automated averaging of two up to
eight speech intelligibility results based on these standard requirements.

• Press enterto confirm. The measurement data is stored
on the SD Card in ASCII format.

 The measurement is completed.
127

STIPA

Start Averaging

Add Cycles• Select the averaging page Avr.

• Press enter• Turn the rotary wheel
to select the parameter START
NEW and press enter .

• Repeat the measurement at the same position as required.

 The first measurement starts automatically. It is labeled
Cyc 1.

128

to confirm Add Cycle.

 The XL2 performs further measurements and adds them tothe list.

STIPA

FinishDisplay of STIPA Numeric Result Page

• Choose Finish to end the averaging.

The symbol
played.

indicates that the averaged STI value is dis-

 The speech intelligibility average and the deviation are displayed for documentation.

129

STIPA

Ambient Noise Correction
Measuring the speech intelligibility index under realistic environmental conditions is often not feasible; e.g., playing the test
signal in a railway station at emergency levels during peak hours
will irritate passengers. Additionally, at rush-hour the characteristics of ambient noise might be highly impulsive, while a
pre-requisite for accurate speech intelligibility measurements
is a negligible impulsivity in the ambient noise. Under such circumstances the speech intelligibility measurement should beshifted to a more suitable time of the day; e.g. night time.

Enable Ambient Noise Correction• Select the correction page Cor.
• Turn the rotary wheel
to select the parameter Ambient
Noise Correction and press enter .

 The correction enables and the XL2 displays this screen:

Measurement Sequence• First measure the ambient noise• Secondly measure the speech intelligibility

This sequence simplifies the measurement
as follows: The XL2 immediately displays the
speech intelligibility result with ambient noisecorrection. This result provides a guideline if
repeated measurements at the same location
with averaging is required. For details see thechapter STIPA Measurement Hints.

130

You may adjust the ambient noise band levels
and the LAeq.

STIPA

Commissioning New PA-Systems
New announcement systems are commissioned e.g. at publicareas prior the grand opening. Thus, the actual ambient noisecaused by the public is not available yet during the speech intelligibility measurement. Here you may simulate the real-life
condition with ambient noise data enabled by one of the following modes:

Measure Ambient Noise• Position the microphone at the STIPA measurement point.
• Select Measure (without any test signal presence).

 The XL2 measures the ambient noise and displays the LEQ
octave band result.

• Utilize a reference noise file, which might be applicable forthe actual project- Measure the ambient noise at another similar project andstore this as reference noise file.
- Back on the actual project select the parameter Load withthe rotary wheel
and press enter .
- Select the reference noise file, which shall be utilized as
ambient noise correction for your speech intelligibility
measurements.
• Edit actual noise data
- Select the parameter Edit or the LAeq level with the rotary wheel
and press enter .
- Turn the rotary wheel to adjust the noise level.
- Press enterto continue the setting.
Skip the next step “Measure Ambient Noise” and go to “STI
Measurement”.

You may edit the noise data.

131

STIPA

STI Measurement• Select the STIPA result page 123.
• Perform the speech intelligibility measurement.

Data Post-Processing
In the case when no ambient noise correction has been carried out on-site with the XL2 Analyzer, you may post-process
your measurement data on the PC. The NTi Audio STI Reporting Tool combines the speech intelligibility measurement takenwith quiet conditions and the actual ambient noise caused by
the public, e.g. during day-time. This emulates the speech intelligibility expected during real-life conditions.

STI Reporting Tool
The STI Reporting Tool creates measurement reports according to the standards• AS 1670.4• CEN/TS 54-32:2015• DIN EN 50849:2017• IEC 60268-16• ISO 7240-19:2007• VDE V 0833-4-32:2016• VDE 0828-1:2017-11

 The XL2 displays the corrected speech intelligibility result
in large font. The actual measured result is listed below insmaller font.

132

Import the data directly from your XL2 including the ambient
noise measurements. The corresponding speech intelligibility
STI or CIS values are shown.

STIPAThe STI Reporting Tool is free to download on the XL2 Support
website https://my.nti-audio.com for all registered users. (Enable all macros when opening the document.)
System Requirements:• PC running Windows OS• Excel 2010 - 2016

STI Measurement Hints
Ambient Noise• The ambient noise has to be sufficiently static during themeasurement. A signal-noise ratio of 15 dB or higher is recommended to achieve best speech intelligibility. Impulsive
ambient noise during the measurement, such as speech,
causes severe measurement errors. The STIPA result is usually too high.
• Fluctuating noise is detected by measuring the direct STI in
the absence of the test signal. Carry out these measurements
at least at a representative set of locations. If the STI is toohigh (e.g. STI > 0,3), the measurement results are likely tobe erroneous. In this case the speech intelligibility measurement should be carried out without the presence of noise.

Utilize the ambient noise correction for such instances.
• At locations with varying conditions (e.g., some public areas
with few people and other areas with crowds) the worstcase speech intelligibility should be measured. Consult the
local regulations (e.g. the NFPA code in the U.S.) for directives concerning measurement locations and number of required measurements under which circumstances.

German Standard VDE 0833-4 Requirements
STI > 0.63 One single measurement is sufficient.
STI < 0.63 Perform three subsequent measurements at thismeasurement position.
• If the maximum result deviation of these threemeasurements is > 0.03 then a further threemeasurements shall be performed.
• If the maximum result deviation of these measurements is > 0.05 then the cause of this instability shall be evaluated and removed.
• The arithmetic average of the performed threeor six measurements has to be reported.

133

STIPA

Utilize the STIPA Reporting Tool for the documentation of yourmeasurements according the standard.
An STI > 0.63 implies that the speech intelligibility is higher
than 0.5 with a confidence level of 95%.

CD-Player• Only high-quality CD-Players should be used to reproduce
the STIPA test signal as only limited time-shifts (+/- 20 ppm)
ensure reliable test results. Pitch control and shock protection should be disabled. We recommend that only professional CD-Players be used. You can verify the time shift of the
CD-Player using a 1 kHz test signal:- Insert the NTi Audio Test CD into the CD-Player and start
track 1, which is the 1 kHz test signal.
- Connect the XL2 directly to the audio output of the CDPlayer and measure the signal frequency in RMS/THD+N
mode. The displayed frequency should be in the range
from 0.99998 kHz to 1.00002 kHz• STIPA test signals from other test system manufacturers
may sound similar but are not compatible. Only the original
NTi Audio STIPA test signal should be used in combination
with the XL2.

134

Measurement• Select measurement positions as stipulated by local regulations. As a guideline, typically position the microphone at 1
- 1.2 meters above ground in sitting areas or 1.5 - 1.8 metersin standing areas. Also, directly in front of the speakers orvery close to a wall are examples of positions that are nottypical.
• The person taking the measurements should be out of theacoustic field, so as not to affect the measurement results.
For this purpose, the measurement microphone can bemounted on a microphone stand and connected with the
ASD Cable to the XL2.
• Low speech intelligibility readings can be caused by- Excessive sound reverberation, echoes or reflections- Poor speaker directivity or speaker coverage- Speaker level setting incorrect; e.g. low signal-to-noise ratio.

Audio Analyzer

6.

Audio Analyzer

The XL2 offers a comprehensive audio analyzer. Broadband
or wideband measurements are offered by the measurement
functions RMS/THD+N and Oscilloscope.
The following measurement functions offer detailed analysis of
the audio spectrum in Volt, dBu and dBV:
• SLMeter/RTA• FFT• 1/12 Oct+Tol (optional)
Just change the measurement unit according your requirements. See the individual chapters for more details.

• If an NTi Audio measurement microphonewith electronic data sheet is connected,
the XL2 will automatically activate the unitdBSPL (dB) for sound level measurements.
• A decreased THD+N performance will occur
with unbalanced input signals when using
switching-type power supplies (approx. 3 dB).
Remove such a mains adapter for critical applications.

RMS / THD+N
The XL2 Audio and Acoustic Analyzer measures the parameters Level RMS, THD+N and frequency simultaneously.

5
1

2

3

4

135

Audio Analyzer

1

136

Filter
Z-Weighting

Frequency Z-weighting with flat frequency response from 20 Hz to 22 kHz. Default measurement setting.

A-Weighting

Frequency A-weighting according
IEC 61672 for low noise levels.

C-Weighting

Frequency C-weighting according
IEC 61672 for high noise levels.

HP-100Hz

Highpass 100 Hz, -200 dB/dec.,
maximally flat magnitude filter,e.g. -60 dB @ 50 Hz

HP-400Hz

Highpass 400 Hz, -120 dB/dec., maximally flat magnitude filter, attenuates
50/60Hz components of test signal

HP-19kHighpass 19 kHz; e.g., to measure a
20 kHz pilot tone level of a public address
system without disturbing the public.

22.4-22.4k

Bandpass filter 22.4 Hz - 22.4 kHz(IEC 468-4)

2

Level RMS
Measures the absolute level of the input signal. The unit’s
dBu, dBV, Volt V, dBSPL, Watt W and dBm are selectable.
The Watt and dBm measurement results are calculated
based on a user-defined Load. The unit dBSPL is not available for the type approved XL2-TA firmware.

3

THD+N
Measures the total harmonic distortion and noise of the
input signal. The distortion measurement, expressed in dB,
linear or in %, is conducted within the bandwidth 10 Hz - 20
kHz. This value is calculated as follows:
THD+N = (Distortion+Noise) / (Signal + Distortion+Noise)4

Frequency in Hz
The XL2 automatically extracts and measures the frequency of the fundamental signal. The XL2 frequency counter
technology even reads the frequency correctly for heavily
distorted signals.

Audio Analyzer

5

Balance Indicator
Indication of the audio signal balance between pin 2 and 3
on the XLR input for input signals > -34 dBu.
The input signal is balanced.
The signal is unbalanced. The level at pin 2 ishigher than at pin 3.
The signal is unbalanced. The level at pin 3 ishigher than at pin 2.

PreNotch Listening
The input signal is audible at the rear speaker orheadphone output.
• Press and hold down the speaker button.

 The pop-up window volume is displayed.

137

Audio Analyzer

PostNotch Listening
The main frequency component is filtered out
by a notch filter, leaving only the remaining signal audible.
• Press the speaker button
ume window.
• Additionally, press enter

to display the vol-Oscilloscope
The scope function visualizes the waveform of the electrical input signal. It automatically triggers to the fundamental frequency and selects the scaling of the X-axis (time) and Y-axis (level)
accordingly. The fundamental, or most dominant, frequency of
the input signals is displayed above the scope screen.

 The post notch listening with auto-gain
function is activated. The maximum gain
setting is 0 dB.

e.g. using a 100 Hz sine test signal connectedto the XL2 input, with the 100 Hz main frequency filtered by the notch filter, the complete
frequency spectrum is available at the speakeror headphone output. This feature allows you tolisten to the actual distortion signal. You therefore hear a noise from the speaker even without
any connected inputs signal!

138

The scope scaling is fixed.

Vibration Meter

7. Vibration Meter

VibMeter / Spectrum

The Vibration Option turns the XL2 Audio and Acoustic Analyzer
into a professional vibration meter with broadband measurements and spectral analysis in 1/3 or octave resolution. The
XL2 Vibration Meter determines vibration acceleration, velocity
and deflection with standard-compliant weighting filters in thefrequency range from 0.8 Hz to 2.5 kHz. Detailed recordingof measurement data and audio files allow for comprehensive
evaluation and reporting. In addition, the XL2 Vibration Meter
comes standard with an FFT analysis and an oscilloscope function. Selectable FFT frequency ranges from 1 Hz to 1.69 kHz
allow a detailed examination of the measured vibrations.

The vibration meter offers different pages:
Page Selection using the Page Button• Press pageto toggle between the 123 VibMeter page
and the CPB page.
Page Selection using the Rotary Wheel• Select the page 123 VibMeter with the rotary wheel• Confirm with enter .

.

The Spectral Limits Option adds functions to the Vibration Meter including a zoom FFT up to 20 kHz and a 1/12 octave band
analysis from 0.73 Hz to 1.36 kHz. Also, it adds the ability torecord reference spectra and set tolerances for pass / fail quality control measurements. The Remote Measurement Option
allows the real-time acquisition of measurement data directly
into a computer application via the USB interface. A documented command set is available.

Page Selection

139Vibration Meter

123 Values: Vibration Meter
Displays the selected broadband vibration level results. You canchange the font size of the result. Depending on the font size
chosen, the XL2 shows 2 up to 4 results simultaneously. The
display of the actual or maximum level can be selected withthe applicable frequency weighting. The peak levels PK or P-P
are real peak levels.

Spectrum: Constant Percentage Bandwidth CPB
Displays the 1/3 or 1/1 octave spectrum of the selected RMS,
peak or peak-peak vibration level. Additionally, the wide band
result B is shown graphically by a bar.

Reporting: Report Setting
Here you set which vibration levels shall be stored in a .txt fileafter the completed measurement. Choose between:
ALL

Stores all vibration levels.

Selected

Stores up to 10 different individually-defined vibration levels.

For details refer to the chapter Reporting.

140

Logging: Setup of Data Logging
The XL2 features a powerful vibration level meter data logger,
which allows you to record all required vibration level values
during the measurement. In the logging page you set which
vibration levels shall be logged over time. For details refer tothe chapter Logging. Choose between:
ALL

Logs all vibration levels.

Selected

Logs up to 10 different individually-defined vibration levels.

Limit LED: Limit Setting
Here you set the function of the limit LED , thereby highlighting any vibration level that exceeds the pre-set limits in orangeor red color. Further, external peripherals are controlled by the
optional Serial I/O Interface based on the vibration level, suchas displaying vibration levels on a large external red-orangegreen lamp. For details refer to the chapter Limits.

Vibration Meter

Overview
Numeric Result Page
The numeric result page 123 Values displays the selectedbroadband vibration level results. You can change the fontsize of the result. Depending on the font size chosen, the XL2shows 2 up to 4 results simultaneously. The display of the actual or maximum level can be selected with the applicable frequency weighting.

Constant Percentage Bandwidth Analyzer Page
The real-time analyzer page
Spectrum measures and displays the 1/3 or 1/1 octave spectrum in the selected frequency
range including the wideband result.

11

1

10

4
5
6

2
7
9

3

8

141

Vibration Meter

1

Vibration Level Result 1
All vibration levels are measured and logged simultaneously. You select which vibration levels should be displayed.

3

Change Parameter• Turn the rotary wheel
to select the parameter Lxx.
• Press enter
to open the selection menu and choose
the wideband vibration level to be displayed.
• Turn the rotary wheel
to select the required test result
parameters and confirm with enter .
Change Font Size
• Turn the rotary wheel
to select the actual test result.
• Press enter
1x, 2x or 3x to set the font size to small,medium or large.
The XL2 shows 2 vibration levels on the display if a large
font is chosen, otherwise it shows 4 vibration levels.
2

Vibration Level Result 2
Follow the setting instructions for vibration level result 1.

4Filter
Select one of the following frequency filters:
FLAT

no filter applied

1-80HzFilter 1 - 80 Hz with decay rate of 12 dB /octave in accordance with DIN 45669-1

1-315Hz

Filter 1 - 315 Hz with decay rate of 12 dB /octave in accordance with DIN 45669-1

10-1000Hz

Filter 10 - 1000 Hz with decay rate of 18 dB /octave in accordance with ISO 2954

Result Symbols / CaptureThis field offers two functions:• Symbols for measurement results 11
Upper parameter displayed as line.
Lower parameter displayed as bargraph.

142

Vibration Meter• Capture
One of the displayed frequency band readings may be
captured. Any measurement data can then be comparedwith this captured reference live on the XL2 Analyzer.

6

Y-Scale setting• Select the Y-Axis with the rotary wheel
and confirm
with enter .
• Select the zoom factor between 20, 10, 5, 2.5 dB/div andconfirm with enter .
• Scroll up and down with the rotary wheel
to select the
Y-axis range.
• Confirm with enter .

7

Measurement Result
Real-time analyzer results in 1/1 octave or 1/3 octave band
resolution.

8

X-Scale setting
Third-octave band resolution• Select the parameter to be captured.
• Confirm with enter , to capture the reading.
• Select the upper parameter 15 and choose Capt.
• Confirm with enter .

 The lower reading can be compared with the previouslycaptured reference data.
5

Level Type
Select in the System Settings:• metric or imperial units• RMS, peak or peak-peak level

Upper parameter displayed as line.

2.5 Hz - 2.5 kHz

frequency band levels including wideband result

0.8 Hz - 1.0 kHz

frequency band levels including wideband result

0.8 Hz - 2.5 kHz

frequency band levels

Lower parameter displayed as bargraph.

143

Vibration Meter

Octave band resolution
4 Hz - 2.0 kHz

frequency band levels including wideband result

1 Hz - 0.5 kHz

frequency band levels including wideband result

1 Hz - 2.0 kHz

frequency band levels• Select the X-Axis with the rotary wheel
and confirm
with enter .
• Toggle with the rotary wheel
between the ranges.
• Confirm with enter .
9

Broadband Results
Displays broadband level B.

10 Filter

Select the preset frequency filter here, which is alreadyused on the broadband page.

144

11 Measurement Result

Actual level result of the indicated frequency band. The cursor readout displays the center frequency and the level ofthe band pointed to by the arrow.
Select the measurement unit as follows:
Acceleration a• m/s2• g• in/s2• dB

Velocity v• m/s• in/s• dB

Displacement d

• m
• in
• dB

Vibration Meter

Wav-File Recording
The XL2 records a wav-file of the measured input signal andstores it on the SD Card. The available formats are:• Compressed (default, using ADPCM compression). A new
wav-file is started automatically after 12 hours of recording(typical maximum wav-file size = 512 MByte)• Compressed+AGC, compressed with automated gain control. The gain control increases the level of low-level signals,
so that the wav-file is well-leveled during playback on thePC.
• 24Bit_48kHz, linear wav-file logging in 24 bit, 48kHz resolution with the optional Extended Acoustic Pack. A new wavfile is started automatically after 1 hour of recording (typicalmaximum wav-file size = 512 MByte)

Broadcast Wave Format BWF
The XL2 stores scaling factor, serial number,date, time and time zone within the wav-file (according to EBU TECH 3285). This information isavailable through professional audio/video tools
typically used in broadcast.

Sample name of wav-file:
MyTest_V_Meter_000_Audio_FS_2.52e2_mps2(PK)_00.wav

1

2

3

4

5

1

MyTestFile name defined by user.

2

SLM
Measurement function.

3000
Automatically incrementing file number.

4

Audio_FS_2.52e2_mps2(PK)Audio file with full-scale peak level based on accelerationin unit m/s2. In case of a Compressed + AGC recording,the file name reads “AGC”; this file contains corrected level
information only.

500
The number increments for each successive wav-file during
a longer recording.

145Vibration Meter

FFT Analysis + Tolerance
The XL2 Vibration Meter includes a fast real-time FFT.
9

The following features are available upon installing the Spectral
Limits Option in the XL2 Analyzer:• High-resolution Zoom-FFT up to 0.4 Hz steps in the frequency range 1 Hz - 20 kHz• Capture and tolerance function provided with Spectral Limits
Option; thus the main menu function reads FFT + Tol.

8

7

1

6

2
3

4

5

146

Vibration Meter

1

Result Symbols / Capture & Start Tolerance Mode
This field offers two functions:• Symbols for measurement results 2

Managecaptures

Upper result displayed as line.
Lower result displayed as bargraph.

• Capture & Start Tolerance Mode
The displayed readings may be captured as reference
reading C1 to C8 for• Comparing measurement results against captured
traces with relative or absolute curve display.
• Creating tolerance masks based on captured reference curves for passed / failed measurements.

Allows to rename captures, clear recorded captures, save captures to the
SD Card for export from the XL2 orload captures from the SD Card for import to the XL2.

Start tolerance Starts the tolerance mode for passed/mode
failed measurements comparing theactual measurement results against atolerance band.
2

Measurement Result
Actual level result of the indicated frequency band. The cursor readout displays the center frequency and the level ofthe band indicated by the arrow.
Upper parameter displayed as line.

Capture EQ

Captures the upper parameter

Capture Live

Captures the lower parameter

Lower parameter displayed as bargraph.
Select in the System Settings:• metric or imperial units• RMS, peak or peak-peak level

147

Vibration Meter

3

Y-Scale setting• Select the Y-Axis with the rotary wheel
and confirm
with enter .
• Select the zoom factor between 20, 10, 5, 2.5 dB/div
and confirm with enter .
• Scroll up and down with the rotary wheel
to select the
Y-axis range.
• Confirm with enter .

4

Measurement Result
Displays the actual and averaged measurement results.

5Time Weighting
Offers selectable time weighting of 0.1, 0.2, 0.5, 1.0 seconds as well FAST (125 ms) and SLOW (1 second).
Applications:Short Time
WeightingHigh-resolution in time with minimum
averaging

Long Time
Weighting

Low resolution in time with longer averaging

6

Readout Frequency
You may select any frequency to read out individual levels.
The selected frequency is indicated by the cursor arrow.
Choose between the following settings:
The cursor follows automatically the highest level,
e.g. tracing the dominant frequency of a rotatingpart.
• Select the frequency with the rotary wheel .
• Press enter .
• You may readout any individual frequency.
• Return to auto frequency with enter .

 The cursor returns to the frequency with highest level bar.
The cursor readout may be set manually to any
frequency. The readout remains at the selected frequency.
• Select the frequency with the rotary wheel .
• Press enter .
• Select the frequency of interest.
• Confirm with enter .

 The cursor readout 2 displays the measurement results of the selected frequency band.
148

Vibration Meter

7

Zoom Mode(optional, applicable with the Spectral Limits Option)• Select the readout frequency 10 and press enter .
• The zoom mode is displayed above the flashing arrow.
• Select the zoom-in frequency with the rotary wheel .
• Press limit
and zoom the linear frequency scale in orout with the rotary wheel .
• Release limit
and scroll the linear frequency scale leftor right with the rotary wheel .

8

Measurement Unit
Select the measurement unit as follows:
Acceleration a• m/s2• g• in/s2• dBa

Velocity v• m/s• in/s• dBv

Displacement d

• m
• in
• dBd

The Spectral Limits Option extends the function with captures and tolerances. All tolerances are specified as acceleration.

149Vibration Meter

9

Page Selector X-Scale and Parameter Setting
1k7

Shows FFT result of the frequency band range.
23 Hz - 1.687 kHz in a resolution of
11.72 Hz with 143 bins shown on the display.

400

Shows FFT result of the frequency band range.
5 Hz - 421.02 Hz in a resolution of 2.92 Hz with143 bins shown on the display.

100

Shows FFT result of the frequency band range.
1 Hz - 105.00 Hz in a resolution of 0.73 Hz with143 bins shown on the display.

Usr

User Range(applicable with optional Extended Acoustic Pack
or Spectral Limits Option)
1 Hz - 20 kHz in zoom mode with a minimum resolution of 0.366 Hz and 143 bins displayed.

Set

Selection for FFT Windowing:• Hann: Default setting• Dolph-Chebyshev: for analyzing small signals(e.g. harmonics) close to a dominant signal.

Oscilloscope
The scope function visualizes the waveform of the electrical input signal. It automatically triggers to the fundamental frequency and selects the scaling of the X-axis (time) and Y-axis (level)
accordingly. The fundamental, or most dominant, frequency of
the input signals is displayed above the scope screen.

The scope scaling is fixed.
The page button
150

switches these display modes.

Vibration Meter

1/12 Octave + Tolerance (optional)
8

The Spectral Limits Option extends the function range of the
XL2 with trace capturing, relative curve display and comprehensive tolerance handling for the FFT Analysis and the highresolution 1/12 Oct + Tol spectral analysis.

7

1

6

2

Features:• Capturing of multiple readings into the internal memory• Comparing measurement results against captures with relative or absolute curve display• Comprehensive tolerance handling• Creating tolerance masks based on captures for passed /failed measurements

3

4

5

151

Vibration Meter

1

Result Symbols / Capture & Start Tolerance Mode
This field offers two functions:• Symbols for measurement results 2

Managecaptures

Upper result displayed as line.
Lower result displayed as bargraph.

• Capture & Start Tolerance Mode
The displayed readings may be captured as reference
reading C1 to C8 for• Comparing measurement results against captured
traces with relative or absolute curve display.
• Creating tolerance masks based on captured reference curves for passed / failed measurements.

Allows to rename captures, clear recorded captures, save captures to the
SD Card for export from the XL2 orload captures from the SD Card for import to the XL2.

Start tolerance Starts the tolerance mode for passed/mode
failed measurements comparing theactual measurement results against atolerance band.
2

Measurement Result
Actual level result of the indicated frequency band. The cursor readout displays the center frequency and the level ofthe band indicated by the arrow.
Upper parameter displayed as line.

152

Capture EQ

Captures the upper parameter

Capture Live

Captures the lower parameter

Lower parameter displayed as bargraph.
Select in the System Settings:• metric or imperial units• RMS, peak or peak-peak level

Vibration Meter

3

Y-Scale setting• Select the Y-Axis with the rotary wheel
and confirm
with enter .
• Select the zoom factor between 20, 10, 5, 2.5 dB/div
and confirm with enter .
• Scroll up and down with the rotary wheel
to select the
Y-axis range.
• Confirm with enter .

4

Measurement Result
Displays the actual and averaged measurement results.

5Time Weighting
Offers selectable time weighting of 0.1, 0.2, 0.5, 1.0 seconds as well FAST (125 ms) and SLOW (1 second).
Applications:Short Time
WeightingHigh-resolution in time with minimum
averaging

Long Time
Weighting

Low resolution in time with longer averaging

6

Readout Frequency
You may select any frequency to read out individual levels.
The selected frequency is indicated by the cursor arrow.
Choose between the following settings:
The cursor follows automatically the highest level,
e.g. tracing the dominant frequency of a rotatingpart.
• Select the frequency with the rotary wheel .
• Press enter .
• You may readout any individual frequency.
• Return to auto frequency with enter .

 The cursor returns to the frequency with highest level bar.
The cursor readout may be set manually to any
frequency. The readout remains at the selected frequency.
• Select the frequency with the rotary wheel .
• Press enter .
• Select the frequency of interest.
• Confirm with enter .

 The cursor readout 2 displays the measurement results of the selected frequency band.
153

Vibration Meter

7

Setting of Test Result Resolution
Set the spectral result display to 1/1, 1/3, 1/6 or 1/12 octave
band resolution as follows:• Turn the rotary wheel
to select the parameter 12 .
• Press enter
to open the selection window.
• Turn the rotary wheel
to select 1/1 OCT, 1/3 OCT,
1/6 OCT or 1/12 OCT• Press enterto confirm.

8

Measurement Unit
Select the measurement unit as follows:
Acceleration a• m/s2• g• in/s2• dBa

Velocity v• m/s• in/s• dBv

Displacement d

• m
• in
• dBd

The Spectral Limits Option extends the function with captures and tolerances. All tolerances are specified as acceleration.

154

Vibration Meter

155

Calibration

8.

Calibration

The XL2 Audio and Acoustic Analyzer meets or exceeds the
specifications listed in the chapter Technical Data.
Instrument Calibration
In order to maintain the high accuracy, annual calibration of
the XL2 Analyzer and the measurement microphone is recommended. The calibration service verifies the complete productspecifications, differences to the last calibration and measures
the frequency response of the measurement microphone. To
enquire about calibration service, follow the RMA guide lines
at www.nti-audio.com.

Microphone Sensitivity
NTi Audio’s ASD measurement microphones and the microphone pre-amplifier MA220 include an electronic data sheet.
The Automated Sensor Detection (ASD) of the XL2 recognizes
the sensitivity and calibration data of the connected microphone. The electronic data sheet, including the microphonesensitivity, is displayed in the menu Calibrte.

156

Environmental Conditions
The sound level meter and calibrator should be exposed to thesame environmental conditions prior any calibration for the following recommended periods:• 10 minutes after a temperature change of 10°C.
• 15 seconds after the static air pressure has changed by
5 kPa.
• 10 minutes after a humidity change of 30% without condensation.
The described calibration method and correction data apply forthe following environmental conditions:• Temperature: -10 °C to +50 °C• Static air pressure: 65 kPa to 108 kPa• Humidity: 25 % to 90 % r.H.
without dew from -10 °C to +39 °C

Ambient Noise
Please make sure that, during the calibration with 114 dB, theambient noise level is lower than 89 dB.

Calibration

Calibration Menu with connected
Measurement Microphone

Calibration Menu without any connected Sensor

1

8
7
6
5
4
2

9

3

157

Calibration

Calibration Menu with connected
ICP Adapter ASD and Accelerometer

1

Phantom Power Supply
48V

The XL2 provides 48 V Phantom power supply
to the connection microphone or sensor.

ASD

An NTi Audio measurement microphone with
automated sensor detection ASD is connected. The XL2 reads the electronic data sheet ofthe microphone and switches the 48 V Phantom power automatically on

48V

Phantom power is switched off.

10

158

2

Electronic Data Sheet of Measurement Microphone
Read out data from the connected microphone.

3

Factory Sensitivity
Factory sensitivity of the connected sensor.

4

Level Type
LZF

Default setting.

LHP100F

Suppressing any low frequency noise, forexample wind during outdoor calibrations.

Calibration

5

Start Field Calibration
Select RUN and press enter to start the sensitivity setting
using an external calibrator.

6

Level of External Calibrator
The reference calibration level is 114 dB. The XL2 Supports
a level setting between 0 dB and 200 dB.

7

Sensitivity
Applicable microphone sensitivity in the range from
1 µV/Pa to 9.99 V/Pa. The sensor detection of the XL2 reads
the sensitivity automatically from the electronic datasheetof the connected NTi Audio microphone or preamplifier.

8

Spectral Correction
Select one of the spectral corrections as applicable. This
selection can be activated in the System Settings Set pageat position 11 . The correction data is listed in chapter Technical Data.

Offno spectral correction.

WP30 1/2”
Community

for horizontal noise incidents using
the WP30 Weather Protection

8

9

WP30 1/2”
Aircraftfor vertical noise incidents using the
WP30 Weather Protection; no spectral correction applies

WP61 1/4”
Community

for horizontal noise incidents using
the WP61 Weather Protection

WP61 1/4”
Aircraftfor vertical noise incidents using the
WP61 Weather Protection; no spectral correction applies

M22xx DF 1/2”

Diffuse-field correction for measurement microphones M2230, M2340,
M2215, M2211

M42xx DF 1/4”

Diffuse-field correction for measurement microphone M4261

Selection Sound Level Meter / Vibration Meter
Sound

Sound Level Meter

Vibration

Vibration Meter

159

Calibration

10

Unit Selection Accelerometer Sensitivity
The accelerometer sensitivity is provided in the range of• 1 µV/(m/s2) - 10.0 V/(m/s2) or• 10 µV/g - 100 V/g

Field Calibration - With External Sound Calibrator
Field-sensitivity setting for measurement microphones with an
external calibrator.
• Turn the rotary wheel
to select the parameter User Calibration 6 and press enter .
• Set the calibration level according to the calibrator used.
• Generate the specific reference signal with the calibrator
onto the microphone.
• Turn the rotary wheel
to select the parameter RUN 5
and press enter .
• The pop-up window Calibration: Calibration running ... appears and changes to Calibration: Successfully finished!
for a successfully completed calibration.
Field Calibration - Manual Sensitivity Setting
In case no external calibration device is available, set the sensitivity of non-NTi Audio sensors manually according to the product specifications as follows:• Select Sensitivity 7 with the rotary wheel .
160• Press enterand adjust the sensitivity with the rotary
wheel .
• Confirm with enter .

Field Sensitivity
The XL2 writes the field-sensitivity setting onto
the electronic data sheet of the connected NTi
Audio measurement microphone, microphonepreamplifier or ASD Adapter. All subsequent
measurements automatically utilize this fieldsensitivity.
In case the measured sensitivity deviates ±1.5
dB for a class 1 microphone and ±3 dB for aclass 2 microphone to the nominal microphonesensitivity, then the XL2 displays the following
message: Measured sensitivity to far (xxdB)
from factory settings. Check calibration leveland microphone!
In doubts kindly contact NTi Audio with the details.

Calibration

Free-field Correction
The following free-field correction shall be applied using theNTi Audio Class 1 Sound Calibrator• M2230, M2340, M2211, M2215: -0.1 dB

Example - Field Calibration• Configuration- XL2 + M2230 Measurement Microphone- NTi Audio Class 1 Sound Calibrator @ 114.0 dB

The following correction shall be applied using the NTi Audio
Class 1 Sound Calibrator with 1/4” adapter ADP 1/4-P• M4260: +0.1 dB• M4261: +0.2 dB• The level 1 at User Calibration shall be set to 113.9 dB(=114.0 - 0.1).

The NTi Audio microphones are free-field equalized measurement microphone. Thus, they already compensate the increased level by the presence of the microphone body in thefree-field. Pressure conditions apply during the calibration.
Therefore, the level in front of the 1/2” microphone diaphragm
differs by -0.08 dB with reference ambient conditions.
• M2230 with 50 mm Wind Screen
The correction value is +0.12 dB and the XL2 has to be set
to a calibration level of 114.0 dB (=114-0.08+0.12).
• M2230, M2340 with 90 mm Wind Screen
The correction value is +0.19 dB and the calibration level on
the XL2 has to be set to 114.1 dB (=114-0.08+0.19).
• M2230, M2340 with WP30 Wind Screen 90 mm
The correction value is +0.19 dB and the calibration level on
the XL2 has to be set to 114.1 dB (=114-0.08+0.19).

1• Select the parameter RUN and press enter.

 The field calibration is completed.
161

Calibration

Applying Correction Values @ M2230
The goal is to measure the sound pressure without the influenceof the microphone in the air. However, the presence of the microphone body in the free-field environment affects already thesound pressure level at high frequencies. The measurement microphone acts at high frequencies like a reflector. The soundpressure increases in front of the microphone capsule membrane. For example, the sound pressure level is 114.0 dB in thefree field prior installing the microphone. Now the measurement
microphone is placed into the free field. The pressure in front of
the capsule is increased by 0.1 dB at 1 kHz. However, since thesound without microphone influence shall be determined, thefree-field equalization of the M2230 compensates this effect. The
XL2 Sound Level Meter reads the accurate measured value of
114.0 dB and not 114.1 dB.
If the Class 1 Sound Calibrator is placed on the M2230 measurement microphone, then the pressure conditions applies to themicrophone capsule. The pressure in the volume of the calibrator
matches the pressure on the membrane surface of the microphone. Now the free-field equalization and the pressure conditions for the calibration have to be taken into account. Thus, theXL2 has to be adjusted to a calibration level of 113.9 dB when using the M2230. This applies for calibrations at reference ambientconditions and an accurate calibrator output level at the reference
sound pressure level.
162

Profiles

9.

ProfilesProfiles are templates of measurement setups. You may define
which profile is loaded at startup, so that the measurements
are carried out always with the same setup and instrument settings.
A remarkable advantage of the XL2 is the flexible user interface. The measurement screens may be personalized and only
a limited subset of the comprehensive functionality enabled
to create simplified operator interfaces. Advanced users may
access all menus, settings and store their preferred measurement configurations. For simplicity the XL2 Audio and Acoustic
Analyzer offers fixed operator interfaces with specific pre-defined settings. The XL2 can boot up with exactly the required
measurement parameters according to the pre-defined instrument configurations. This ensures accurate measurements areachieved in both advanced and basic usage environments.

Profiles - Getting Started
Activate Profile Selection at Startup• Select Show profile list 1 in the System menu.
• Press enterto activate Yes. This will show the profile listat startup.

1

 The profile list is shown next time you power up the XL2.

163

Profiles

Preset Measurement Function

Store MyProfile• Start the XL2 Analyzer in Full mode.
• Select the typically-used measurement function and adjust
the measurement parameters according to the requirements.

• Select Profile in the main menu and press enter

For example, measuring the sound levels LAF, LAeq and
LAFmax for 10 seconds:

164

 The profile menu opens.

.

Profiles• Select Manage and press enter.

 The Manage Profile menu opens.

Each stored profile includes all settings of all
measurement functions and pages. Only thefollowing details are not stored:• Calibration settings• System settings• Temperature unit
• Phantom power on/off• Select Save Profile and press enter.

 The Save Profile menu opens.

• Select Rename and press enter .
• Set the profile name to MyProfile. The maximum namelength is 20 characters.

165

Profiles• Select Configure available screens and press enter.

Select Profile at Startup• Switch on the XL2

 The profile selection is shown on the display.

• Select additional available pages/measurement functions forthe profile; e.g. RTA.
• Press escapeto return to the Save Profile screen.
• Set Append mode available: yes in order to have the append data feature available in the memory menu.
• You may enable manual measurement range setting withinyour profile. Select Allow manual ranging: yes.
• The correction values defined in KSET may be part of the
profile for selectable profiles with different corrections.
• Select Save and press enter .
166• Select the profile MyProfile and press enter.

 The XL2 starts up with the pre-configured settings forsound level monitoring.

Profiles

Select Profile during Operation• Select Profile in the main menu and press enter The profile menu opens.

.

Run Measurement
The profile name is displayed when a measurement function
is highlighted. The main menu offers only the measurement
functions enabled by the profile, plus the calibration and profile
menu.
• Press start.

• Choose Select and load the required profile.
• Wait 10 seconds until the measurement is finished.
• To return to the full mode either switch off the XL2or select EXIT Profile in the main menu.

again

167

Profiles

Export MyProfile to PC
If you have two or more XL2 Audio and Acoustic Analyzers,
you may like to transfer the same profiles to the other instruments.
• Select Profile in the main menu and press enter• Select Manage and press enter .
• Select Export to SD-Card and press enter .

.

 The XL2 generates a folder on the SD Card called “Profiles”.

Import MyProfile from PC• Connect another XL2 to the PC and generate a folder called“Profiles” on the SD Card.
• Copy the profile called MyProfile into the folder “Profiles”.
• Start up the XL2, select Profile in the main menu and press
enter .
• Select Manage and press enter .
• Select Import from SD-Card and press enter .

 MyProfile is available on the other XL2 Analyzer.

All available profiles are exported into this folder.
• Connect the XL2 to the PC.
• Copy/paste the profile called MyProfile to the PC.

168

If the profile is exported from an XL2 Analyzer
with activated options to another XL2 Analyzer
without options, then these options have to be
hidden prior to storing the profile for export:• In the exporting XL2 system menu, select theindividual option and toggle with enter
to
Hidden.
• Store the profile in the XL2 Analyzer.

Profiles

The XL2 can store up to 20 individual profiles in the internal
system memory and offers three different profile types:
Types
Factory
default
profilesDescription
The XL2 includes factory default profiles, which
are marked with “#” in the beginning of the file
name. Sample filename: #DIN15905-5.prfs
The factory default profiles are a freedownload for all registered XL2 customers on the support website athttps://my.nti-audio.com. For details see thechapter My NTi Audio.
For detailed settings of factory default profiles
please see the Appendix 2 in this manual.

User
profilesUser profiles are profiles generated by you on
the XL2 Analyzer.
Sample filename: MyProfile.prfl

SecuredprofilesSecured profiles are locked user profiles withoverwrite protection indicated by the file nameending in “xxx.prfs”. This file name cannot be
overwritten.
Sample filename: MyProfile.prfs
How to generate secured profiles• Export the profiles to SD Card according to
the procedure in the chapter Profile - Getting
Started.
• Connect the XL2 to the PC.
• Select the user profile in the folder “Profile”.
• Manually change the ending of the user profile from “xxx.prfl” to “xxx.prfs”• Disconnect the XL2 from the PC.
• Import the profiles from the SD Card
• Power off/on
the XL2 Analyzer

 The secured profile is displayed with a locksymbol in the profile selection window onstartup of the XL2.

169

Capture + Tolerances

10. Spectral Limits Option(Capture + Tolerances)

Capture the EQ Measurement Results• Select the Capture & Start Tolerance Mode symbol for capturing the measurement result.

The Spectral Limits Option extends the function range of the
XL2 with trace capturing, relative curve display and comprehensive tolerance handling for the FFT Analysis and the highresolution 1/12 Oct + Tol spectral analysis.
Features:• Capturing of multiple readings into the internal memory• Comparing measurement results against captures with relative or absolute curve display• Comprehensive tolerance handling• Creating tolerance masks based on captures for passed /failed measurements• Confirm with enter

170.

Capture + Tolerances A pop-up window appears.

 The pop-up window ... and store it to appears.

• Select Capture EQ.
• Confirm with enter .

• Select C1.
• Confirm with enterand set the capture name in the displayed letter selection box e.g. to Ref.

 The capture has been stored in the internal XL2 memory.
171

Capture + Tolerances

Edit Capture Manually• Select the Capture & Start Tolerance Mode symbol.
• Confirm with enter .
• Select Manage captures.
• Confirm with enter .
• Select Save to SD card.

 The pop-up window Save captures appears.

See the difference between Live Level and Capture• Blank the upper parameter by setting ----.
• Select the lower parameter with the rotary wheel .
• Confirm with enter .
• Select Live and confirm with enter .

 The pop-up window Select reading mode appears.

• Select the capture to be exported, e.g. C1.

 The pop-up window Save capture C1 to appears.
• Confirm with Save.

 The XL2 generates the file MyCapture.txt in a new folder
called Captures.
• Edit the sound level data in the capture file. All frequency
data has to remain the same.
• Load the new capture file with Manage captures back into
the internal XL2 memory.
• Select Live - for displaying the relative difference.
• Confirm with enter .
• Select Ref and confirm with enter .
• Set the Y-axis accordingly to show the zero-line.
172Capture + Tolerances The relative difference between the Live level and the captured reference is displayed.

Manual Editing of Capture Data
Kindly observe the following rules while manually editing capture data:• The spectrallevelAnalyzer
data isZ-weighted, thus the sum of all%1/12 Octave
Capturebands has
to
equal
the
Z-weighted
broadband level.
%‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐DO NOT EDIT THIS SECTION‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐• The A andC-weighted
broadband
levels are calculated ob#Capture time
serving22.04.2015
the corresponding
correction factors.
13:55#Levelifunit• Enter -999
nothing shall be deducted at certain broadband
levels ordBrfrequency bands.
#Octave resolution
1/1 Octave%‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐EDIT ONLY LEVELS HERE!‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐#A‐weighted broadband level
32.74#C‐weighted broadband level‐999#Z‐weighted broadband level
33.17#Columns
Frequency#Spectrum

All levels differences (relative levels) are displayed in the unit dBr.

16
31.5
63
125
250
500
1000
2000
4000
8000
16000

Level
‐999
‐999
‐999
10.5
20.5
25.7
28.6
25.5
23.4
24.5
‐999

173

Capture + Tolerances

Start Tolerance Mode for Passed/Failed Measurements• Select the Capture & Start Tolerance Mode symbol with therotary wheel .

• Confirm with enter174.

 A pop-up window appears.

• Select Start tolerance mode.
• Confirm with enter .

Capture + Tolerances

Passed Result

 The pop-up window Make tolerance from appears.

 The tolerance mode is active for passed/failed measurements.
The passed/failed condition is further visualized by the bicolor“limit” button and forwarded to the I/O interface of the instrument in order to drive an external alarm device such as theaccessory SPL Stack Light.
2

3

1• Select Ref to load the earlier captured reference spectrum.
• Confirm with enter .

You may press the page button
to toggle
between the date and spectral resolution dataof the capture.
175

Capture + Tolerances

1

PASSED / FAILED Result
PASSED

The actual measurement result is within thetolerance band.

Failed Result
The XL2 Analyzer compares spectral measurements against atolerance band and visualizes exceptions 1 in every frequency band.

The actual measurement result is outside of
the tolerance band. Exceptions are visualized in any out-of-tolerance frequency band.
2

Tolerance Bandwidth
Adjusts the tolerance bandwidth based on the captured reference spectrum in dB.

3

Level Offset
Provides a level offset in dB to shift the tolerance band up
or down.

1

Select another Tolerance File• Select the tolerance Ref with the rotary wheel .
• Confirm with enter .
• Select the new tolerance file from the SD Card or the internal
XL2 memory.
176

Capture + Tolerances

Tolerance Menu

1

2

Advanced Start Functions
You may start the passed/failed measurement in one of thefollowing ways:• Press the XL2 start button.
• Activate the automated level trigger in the tolerance file.
• Activate the digital input 1 via the external I/O interface; e.g.
a foot switch or a PLC control.

3

Digital I/O Interface
Result Passed:		
Result Failed:		
Start Measurement:1

Capture & Start Tolerance
Opens capture and tolerance menu.

2

Tolerance Type
Select between high/low, high or low tolerance band basedon the reference data set.

3

Frequency Range
Setting of start and stop frequency of the tolerance band.

Output 1
Output 3
Input 1

Tolerance Management
Tolerance curves can either be imported from txt-files or directly derived from captured measurements. The XL2 calculates
tolerance bands based on• Single captured results• txt-files generated manually on a PC
• Mean average of multiple captures• Min/Max curves of multiple captures

177Capture + Tolerances

Create Tolerance Files Manually on PC• Capture a spectrum on the XL2 Analyzer.
• Enter the tolerance mode and generate a tolerance band forthe capture.
• Select the Capture & Start Tolerance Mode symbol.
• Confirm with enter .
• Select Save tol. to SD Card to export the capture tolerance
file. This file includes the reference capture and the tolerance
data. The XL2 generates a txt-file in the folder “Tolerances”.
• Open the capture tolerance file with a text editor or MS Excel.
• Edit the tolerance data according to your requirements.
Change only the Min, Ideal and Max column values. You may
delete rows, but do not change the frequency column values. Any rows where frequency column values have beenchanged will be discarded by the XL2.
• Store your individual tolerance file as a txt-file in the XL2
folder “Tolerances”.
• Start the XL2 tolerance mode and load the new tolerance filefrom the SD Card.

178• All entries in the customized tolerance fileneed to be tab-separated.
• The individual tolerance file entries may be in
any order; no sequential order required.
• Tolerance file templates and standardized tolerance files are a free download for all registered XL2 customers on the support website
at https://my.nti-audio.com. For details see
the chapter My NTi Audio in this manual.

Capture + TolerancesBand-limited Measurement Range
Alternatively to the settings on the XL2, the tolerance may also
be limited to a range of frequency bands or a number of individual frequencies on a computer.

The XL2 shows selectable broadband values with A, C or Zweighting on the right-hand side of the spectrum.

• Open the tolerance file on the computer.
• Delete all not required frequency bands.
• Set #Hide UnusedBands to True.
• Save the file changes.
• Load the updated tolerance file in the XL2.

Alternatively select the following averaged or summed levels:• Bands E-Sum: Sum of displayed frequency bands• Bands E-Mean: Energy-averaged level of displayed frequency bands, e.g. the bands 80 dB and 70 dB produce 77.4 dB.
• Bands A-Mean: Arithmetically-averaged level of displayed
frequency bands, e.g. the bands 80 dB and 70 dB produce
75 dB.
179

Capture + Tolerances

#Unit
dBr
#Mode
HighLow#Columns
Frequency

Min

Ideal

#Unit

dBr (relative), fixed setting#Mode

Describes tolerance type; the XL2 allows setting of the tolerance type independently of thetolerance file.

Max#ATolerances
UNDEF

80

undef

90

#ZTolerances
UNDEF

80

undef

90

#BandTolerances
20
1000
1000
4000
4000
20000

70
70
73
73
70
70

undef
undef
undef
undef
undef
undef

80
80
77
77
80
80

#nAllowedViolations
0

180

Utilizes upper and lower tolerance based on ideal reference.

High

Utilizes only upper tolerance
based on ideal reference.

Low

Utilizes only lower tolerance
based on ideal reference.

#Columns

Column headings for further tolerance data
separated into columns:
Frequency / Min / Ideal / Max#ATolerances

Defines the tolerance band for the
A-weighted wideband level (not mandatory).

#CTolerances

Defines the tolerance band for the
C-weighted wideband level (not mandatory).

#LevelOffset
0#HideUnusedBands
false

HighLowCapture + Tolerances#ZTolerances

Defines the tolerance band for theZ-weighted wideband level (not mandatory).

#BandSum
Tolerances

Defines the tolerance band for thesum of displayed frequency bands (not mandatory).

#Band
Tolerances• Defines the tolerance band for the individual
frequencies.
• The ideal parameter can be set as “undef”.
• The same frequency value on two successive rows defines a tolerance step, e.g.:#LevelOffset

Frequency

Min

Ideal

Max

100

70

75

80

500

70

75

80

500

75

80

90

1000

75

80

90

#Hide
Defines the way measurement results are
UnusedBands shown.

#nAllowed
Violations

True

Measurement results of frequency bands without any
specified tolerance are notdisplayed. The total level of all
shown bands (sum of bands) isavailable as a broadband result.

False

The measurement result of all
frequency bands are shown.

Allows a PASSED result with a maximum
number of n failed frequency bands (not mandatory)

All levels in the tolerance file are relative levels
dBr. Thus, the level offset provides the relation
between the relative level and actual soundpressure level. (not mandatory)
The XL2 allows setting of the level offset independently of the tolerance file.
181

Capture + Tolerances#FreqScale
Spacing#AutoStart

Defines the frequency scale spacing in the Xaxis for the tolerance data. (not mandatory)lin

Tolerance data displayed withlinear frequency spacing, e.g.
used in the FFT function. (default setting)log

Tolerance data displayed withlogarithmic frequency spacing
e.g. used in the 1/12 Oct + Tol
function.

Enables auto start function. (not mandatory)
True

False

182

Auto start is active. The run indication displays A. The measurement starts automatically after
the trigger level is reached.
Alternatively the measurement
may start manually by pressingstart.
No auto start function. (default
setting)#AutoStartTrig- Sets the sound level in dBZ for an automatedgerLevellevel trigger; the passed/failed measurement
starts as soon as the set level e.g. 95 dB isreached or exceeded. The actual input levelcan be monitored at the input range bar. (mandatory if #AutoStart is True)#AutoStartSet- Defines the settling time, after the auto starttlingTime
trigger level is exceeded, until the start of themeasurement; the time is set in 100 millisecond steps e.g. setting 0.5 equals a settling
time of 0.5 seconds. If the input level drops
below the auto start trigger level during thisperiod, no measurement is carried out. (notmandatory)#MeasTimeDefines the measurement time in 100 millisecond steps; e.g. setting 1.5 equals a measurement period of 1.5 seconds. (not mandatory)#FailDeadTime Defines the delay for a failed condition in seconds; for example, the XL2 triggers “failed” if
the measurement result is beyond the tolerance limits for e.g. 60 seconds. This feature
supports condition monitoring applications.
(not mandatory)

System Settings

11. System Settings

2

The various system settings of the instrument can be adjusted
as follows: Turn the rotary wheel
to navigate to the main
menu 1 and select System. Confirm with enter .

Page Selector
Toggles with the page button
Set

System setting

Vib

Vibration (applicable only upon installing the Vibration option and selecting the vibration menu)

Sch

Scheduler

Opt

Options

Inf

System information

Settings
1

2

between

3
4
5

6
7
8
9
10
11

3

Auto power off
If no button has been pressed for the defined time period,
then the instrument switches off. The auto power off mode
is disabled when a measurement is running or when an
external mains power supply is used.
• Select Auto power off with the rotary wheel .
• Confirm with enter .
• Set the auto power off time with the rotary wheel• Confirm with enter .

.

183

System Settings

4

Backlight
Toggle the backlight with the power/backlight button
The backlight offers three different conditions:• On• Dimmed• Off

Auto On/Off

The backlight switches off if no key ispressed for 2 minutes.

Date and Time Setting
The XL2 includes a real-time clock. All measurements arelogged with a date and time stamp.
Time Zone

Select your time zone

DST/ Summer time

Activate this for daylight saving

Date

Date in yyyy:mm:dd
Time in hh:mm:ss

Auto
On/Dimmed

The backlight dims if no key is pressedfor 2 minutes.

Time

ManualThe backlight can be toggled between
On, Dimmed and Off.

Set the real-time clock as follows:• Select the Date function 5 with the rotary wheel• Confirm with enter .
• Set the date with the rotary wheel .
• Confirm each setting with enter .
• Follow the same procedure for Time.

• Navigate the cursor to the backlight function.
• Toggle with enter
to set this parameter.

Dimming the backlight reduces the power
consumption.

184

5

.

 You have set the real-time clock.

.

System Settings

6

Show Profile List
You may configure the XL2 to start up with individual preset
application profiles. For example, sound level monitoring inaccordance with DIN 15905 or V-NISSG.
Yes

Speaker
Enables/disables the rear speaker. For example, it is recommended that the rear speaker be disabled for all acoustic
measurements. This prevents measuring the audio feedback sound loop generated through the rear speaker.

9

USB ModeThis defines how the PC recognizes the connected XL2:

The instrument starts up in the last configuration
without any application profiles.

Ask onconnect

Select either the Mass storage or COM portmode after connecting the XL2 to the PC.

Phantom PowerYou can select if the phantom power should be activated or
disabled when the XL2 is powered up.

Massstorage

The PC recognizes the XL2 as a mass storage
device automatically, allowing you to download XL2 measurement reports.

COM
port

The PC recognizes the XL2 as a COM port automatically for application of the XL2 Projector
PRO and the Remote Measurement Option.

No

7

The instrument starts up with default application
profiles. Further details about the application profiles are in the chapter Profiles.

8

OffThe phantom power is switched off when
the XL2 is powered up; e.g. when it iscommon to measure lines.

Remember

The XL2 remembers the setting prior to
the last shutdown. (= default setting)185

System Settings

10 Decimal Separator

Set the decimal separator to match the generated measurement reports to the PC settings. This simplifies data
post-processing on the PC.
• Navigate to the Dec. Separator function 8 with the rotary wheel .
• Toggle between “ . ” and “ , ” with enter
to set thisparameter.

Vibration
This page is available upon switching to the vibration menu,
which requires an installed Vibration-Option. Vibration is selected in the calibration menu.

1 The decimal separator is set.
11

186

Calibration Menu Setting
Setting of the calibration menu.
Standard

The default calibration menu is displayed.

Show
Spec.
Corr.

This setting is required to activate the required weather protection or diffuse-fieldcorrection in the calibration menu.

2

1

Selection Metrical-Imperial Units
Units selection

2dB Reference
Definition of the reference parameters for dB results

System Settings

Scheduler

1
2
3

4
5

The XL2 Analyzer offers automated scheduled measurements
without any human interaction. You may schedule a measurement for one or multiple days or ever.
XL2 Actions after pressing Start Schedule• Selects the preset measurement function.
• Standby until start time
• Starts measurement at start time
• Stops measurement after the preset measurement duration• Stores measurement data to SD Card (no reconfirmation required)• Stops schedule or standby until next start time.

6

7

Supported measurement functions:• SLMeter/RTA• FFT + Tol• RT60• 1/12 Oct + Tol• STIPA

187

System Settings

1

Function
Select the measurement functions for the scheduled measurements.

2

Start Date and Time
Set the date for the scheduled measurement(s):• Select Start with the rotary wheel .
• Confirm with enter .
• Set the date with the rotary wheel .
• Confirm each setting with enter .
Set the time for the scheduled measurement:• Select the T symbol to the right of the date.
• Confirm with enter .
• Set the time with the rotary wheel .
• Confirm each setting with enter .

3

Scheduled Duration
Set the scheduled duration of the measurement(s). The actual settings of the selected measurement function apply.

4

Recurrence

188

Off

Schedules a single measurement.

On

Schedules a measurement sequence with thesame start and end time for the selected days.

5

Days
Select the week days for the recurrence

6

End
Set the number of occurrences of the scheduled measurement. Each week day is one occurrence. Select between
1 to 99 occurrences or an endless schedule (= never).

7

Start Schedule
Starts the scheduled measurement(s).

 The Scheduler active window is displayed.

System Settings

Scheduling - Getting Started

Options

After starting the scheduled measurement, the XL2 waits forthe next scheduled start date and time. The instrument buttons
are disabled.
Power Supply
It is recommended that the instrument remains powered on
until the next start time, using the accessory mains power
adapter. If the XL2 is powered off and on again during this time,then the XL2 Analyzer restarts in the Scheduler function andcontinues the countdown. This applies also for any interruptionof mains power supply.
Stopping the Scheduler
Press and hold the start/stop button
to stop the scheduler
prior to the start of the measurement or as an interrupt of any
ongoing scheduled measurement.
Displays the options installed on the XL2.
Operation with PC
Starting the schedule switches the USB interface automaticallyinto the COM port mode for remote measurement applications
or using the XL2 Projector PRO software.

Every installed option may be temporarily Hidden to generatea profile for other XL2s without this option installed.
• Select the installed option.
• Toggle with enter
to set this parameter.

189

System Settings

Information

1
2

1

Serial Number
Displays the instrument’s serial number.

2

Firmware
Displays of the firmware version number (to update thefirmware to the latest version see the chapter Firmware
Update of XL2.

190

Data Management

12. Data Management

1

Create New Project Folder
Add a new folder with an individual project name. The maximum length of the project name is 16 characters. A fast
way for creating new folder names is• Select an existing folder name with DIR• Select NEW• Rename the folder and confirm with start, thereby
creating a new folder name.

2

Select Project Folder
An overview of all existing project folders is shown. Selecta folder to store the results of the measurements.

3

Project Folder Name
All measurements are stored in this project folder.

4

Autosave
Setting of auto or manual data file naming and saving

The XL2 stores all acquired measurement data including realtime information onto the removable SD Card. Additionally,
wav-files might be recorded and individual voice notes added
for a complete documentation of the measurement.
• Carry out a sound level measurement.
• Select the memory menu
in the upper menu bar.
• Press enter . The memory menu opens.
1

2

3
4
5
6
7
8

On

The results are named and stored automatically in the selected project folder.

Off

A question mark appears in the upper menu
barat the end of the measurement. You
can choose to individually name and store
each single measurement.

9
10

191

Data Management

Assisted

A pop up menu appears after each measurement. You may select to keep or delete thestored measurement records.

9

Free Memory
Displays the remaining available memory on the SD Card.

5

Save TestStores the measurement in the selected project folder.

The XL2 prevents a memory overflow. SD Cards are not designed for a 100% memory usage; the XL2 keeps at least
2% or 50 MB empty.

6

Save Screenshot
Stores the XL2 screen in the selected project folder.

The XL2 deactivates the audio recording 50 MB before thislimit is reached and reports this on the display.

7

Load Test
Loads back previously-stored result data from the SD Cardfor detailed examination on the instrument screen.

8

Append Mode
The append mode stores one or more results into the samedata file, simplifying data analysis and handling on the PC.

In the case where only 2% or 50 MB remains, the XL2• deactivates the data logging and reports this on the display.
• disables Save Test and Autosave• saves the report at the end of the current measurement.

Application example:
When measuring the acoustic spectrum at various locations within the same venue, the append mode allows you
to store all the measurement results into one single data
file.

192

Data Management

10

Write Cache (available with Extended Acoustic Pack)
A low Write Cache level indicates that the SD Card is performing well. The optional Extended Acoustic Pack withsimultaneous 100ms logging and linear wav-file recording
results in high data volumes being written to the SD Card.
Some non-original SD Cards may overload (OVLD), causing the loss of some measurement data. Verify the Write
Cache of your SD Card during your measurements. Use
only original SD Cards. We recommend SD Cards from the
manufacturers SanDisk and Transcend.

Original SD Cards ensure that all measurement
data and audio wav-files are stored in good order on the SD Card. Non-original SD Cards maylead to low performance or errors.
Order information: see chapter Accessories.

In case the SD Card is full, you can insert theoriginal spare SD Card into the XL2 and continue with the measurements. The XL2 generates
the projects and system folders automatically.

Memory Structure of SD Card

1
2
3

1

Projects
The folder Projects contains subfolders with the stored
measurement results. The default subfolder name is“MyProject”. You can create further individual subfolders.

2

XL2.htm
This file opens the XL2 instrument status page, with Serial
Number, Firmware and Installed Options.
The page also provides links for online• Firmware updates• Activation of Options

3

XL2_SYSThe XL2 system folder contains a file with serial number,
firmware version and installed options - DO NOT EDIT THIS
FILE.
193

Data Management

Measurement Data - Getting Started
Enable Data Logging• Select the Log page in the sound level meter function andset the logging parameters; e.g., as follows: The data logging is enabled. The sound pressure level will
be logged each second while the measurement is running.

194

Select Parameters for Measurement Report• Select the Rep page in the sound level meter function andset the parameters as follows:Data Management

Complete the Measurement• Press page
to return to the numeric result page.
• Press start. The sound level measurement is now running.
• Press stop
to complete the sound level measurement.

 The measurement data is stored automatically using thefactory settings. In the memory menu
sisted” is activated.

Manual Data Saving• In the case when the instrument is used with the setting
Autosave: Off, a question mark appears after the completed
measurement.
• Now you may store the measurement data manually.
• Select the memory menu
with the rotary wheel
andconfirm with enter .

„Autosave: As-• Press enterto confirm Save Test.

 The pop-up window Save Test appears.
195

Data Management

Select File Name

• Name the first part of the file name. The maximum length of
the first part is 12 characters. The next part “_SLM_001” isdefined by the XL2 to avoid overwriting of existing measurements, whereby “SLM” is the appendix for the measurement function and “001” is an automatically-incrementing
number.

196

Predefined Save Names
Generate a text file with user defined savenames, such as “Room1”, “Room2”, ..., andstore it as “savenames.txt” in the root directoryof the XL2. Just use names with letters or numbers - special characters are not supported.

The XL2 displays the first line of the txt-file in
the Save Test selection menu at manual datasaving.

Data Management

Record Voice Notes

Save Measurement Data

With the internal voice note microphone, record a Voicenoteto save with the test to remind yourself at a later stage where
and/or under which conditions the measurement was done.
• Select Record Voicenote and press enter .

• Select SAVE and confirm with enter.

 The measurement data including test configurations and alllog files are stored on the SD Card.
• Select REC and press enter .
• Record the voice note and press enter The voice note has been recorded.

to finish.

Overwrite File
Disabling Automatic Numbering allows results
to be overwritten with new results.

197

Data Management

Save Screenshot• Select the memory menu
confirm with enter .

with the rotary wheel

and The memory menu opens.
• Select Save Screenshot and press enter .
• Select the file name and confirm SAVE with enter The screenshot is saved to the SD Card.

198.

Measurement Data Logging:
If the battery runs out while you are measuring with logging and/or repeated-reporting enabled, the XL2 creates the folder RESTORE_AFTER_POWERFAIL and stores the measurement
data up until the switch-off time. The next time
you switch on the XL2, the following window
informs you that this data exists. Click OK:

There may be invalid data at the end of the file,which you can delete manually to create a valid
report.

Data Management

 The PC recognizes the XL2 as a mass storage device. The

View Project Folder on the PC• Connect the XL2 with the USB cable to the PC.

following SD Card content is shown: The pop-up window USB Mode appears.

• Open the folder “Projects” and the subfolder “MyProject”.

 All stored measurement data files are shown.

• Select Mass Storage and confirm with enter.

If the XL2 is started with USB connection to PC,
then the COM port mode is automatically activated for remote measurement or the XL2 Projector PRO software. Therefore, if you want toaccess the data in the SD Card, then first start
the XL2 and thereafter connect the USB cableto the PC.
199

Data Management

Overview of Measurement Data Files

3

Measurement Report File
Final report after the completed measurement. For moredetails please see the chapter Sound Level Meter: Reporting.

4

Wav-File
The wav-file is the recorded audio file. The index“FS133.0dB(PK)” in file name represents the full-scale
peak level of the recorded wav-file. For more details please
see the chapter Sound Level Meter: Wav-File Recording.

5

RTA Log File
The XL2 logs the detailed real-time analyzer spectra in predefined time intervals. For more details please see chapter
Sound Level Meter: Logging.

6

Voice Note
A voice annotation can be recorded for each stored measurement or screenshot. For more details please see thechapter Data Management: Voice Notes.

7

Screenshot
Picture of the actual XL2 display.

1
2
3
4
5
6
7

1

2

200

Test System File
System file for use by XL2 only. It contains the measurement data and test configuration of the last measurement
cycle for later reload and view of measurement results in
the XL2.
Sound Level Log File
The XL2 logs sound levels in pre-defined log time intervals.
For more details please see the chapter Sound Level Meter: Logging.

Data Management

The log data file may become very big duringlong-term measurement applications. As soon
the file size reaches 2 GB during the ongoingmeasurement, the file is saved with the index 1
and a new data file created with index 2.
XL2 Data Explorer Software combines all thesedata files together seamlessly.

Transfer Measurement Data to PC• Drag and drop the required data files to the PC.

Card Reader
Alternatively the SD Card can be inserted intoa card reader. This offers a faster data transferfrom the SD Card to the PC.
Additional Data Files using Repeat Mode
For sound level measurements with timer mode
Repeat or Repeat Synchronized the following
additional data files are generated:• MyTest_SLM_000_123_Report_Rep.txt• MyTest_SLM_000_RTA_Report_Rep.txt
Common xxx_Report.txt files contain the measurement data of the last measurement cycle.
The xxx_Report_Rep.txt file contains the resultsof all measurement cycles in the Repeat or Repeat Synchronized mode.
Microsoft Excel
The generated .txt files are best viewed on the
PC using “Open with” -> Microsoft Excel.

201

Data Management

Log File Format
File name: e.g. MyTest_SLM_000_123_Log.txt
XL2 Broadband Logging---------------------

Report File Format
File name: e.g. MyTest_SLM_000_123_Report.txt

MyProjects\MyTest_SLM_000_123_Log.txt

XL2 Sound Level Meter Broadband Reporting-----------------------------------------# Hardware Configuration
XL2, SNo. A2A-02673-D1, FW2.20
Device Info:
Mic Type:
NTi Audio M4260, S/N: 1486, User calibrated 2011-04-05 13:56
Mic Sensitivity: 27.3 mV/Pa# Measurement Setup
Timer mode:
Timer set:
Log-Interval:
k1:
k2:
kset Date:
Range:# TimeStart:End:# Hardware Configuration
XL2, SNo. A2A-02673-D1, FW2.20
Device Info:
Mic Type:
NTi Audio M4260, S/N: 1486, User calibrated 2010-11-05 13:56
Mic Sensitivity:
27.3 mV/Pa

continuous--:--:-00:00:01
0.0 dB
0.0 dB
k-Values not measured
30 - 130 dB# Measurement Setup
Append mode:
Timer mode:
Timer set:
k1:
k2:
kset Date:
Range:

OFF
continuous--:--:-0.0 dB
0.0 dB
k-Values not measured
30 - 130 dB

2011-05-15, 17:44:06
2011-05-15, 17:44:16# Broadband Results
Start
Date
[YYYY-MM-DD]
15.11.2010

Time[hh:mm:ss]
17:44:06# Broadband LOG Results
Date
Time
[YYYY-MM-DD] [hh:mm:ss]
15.11.2010
17:44:07
15.11.2010
17:44:08
15.11.2010
17:44:09
15.11.2010
17:44:10
15.11.2010
17:44:11
15.11.2010
17:44:12
15.11.2010
17:44:13
15.11.2010
17:44:14
15.11.2010
17:44:15
15.11.2010
17:44:16
15.11.2010
17:44:16

Timer[hh:mm:ss]
00:00:01
00:00:02
00:00:03
00:00:04
00:00:05
00:00:06
00:00:07
00:00:08
00:00:09
00:00:10
00:00:10# Broadband LOG Results over whole log period
15.11.2010
17:44:16
00:00:10

LAeq_dt
[dB]
97.0
85.8
73.8
79.0
72.6
67.3
91.2
92.7
79.3
78.0
50.9

LAeq
[dB]
97.0
94.3
92.5
91.4
90.4
89.6
89.9
90.4
89.9
89.5
89.3

89.3

89.3

LAFmax_dt LCPKmax_dt
[dB]
[dB]
102.4
119.0
91.9
105.7
85.2
102.4
85.3
103.9
75.9
94.8
71.4
87.3
95.3
112.3
97.1
113.2
81.6
97.9
82.5
98.1
67.4
79.9
102.4

119

Level LAeq_dt “delta t”
Level within the logging interval. e.g. If the logging
interval is 1 second, then LAeq_dt is the timeaveraged level of each second.

202

MyProjects\MyTest_SLM_000_123_Report.txt

Stop
Date
[YYYY-MM-DD]
15.11.2010

Time[hh:mm:ss]
17:44:16

LAeq
[dB]
89.3

LCPKmax[dB]
119.0

Data Post-Processing
A Microsoft Excel form generating an automated sound levelmeasurement report and chart is available as a free download
for all registered XL2 customers on the support website athttps://my.nti-audio.com. (Enable all macros when opening the
document.)

Data Management

XL2 File Validator
A check sum is written to the file at the end of every measurement report. The XL2 Analyzer calculates the check sum automatically based on the data content of the file. Using the XL2File Validator PC-software, the contents of a data file may beverified at any time. e.g. authorities can verify if the XL2 report
file is original or the data has been manually modified.
The software ”XL2 File Validator” is available for download for
all registered XL2 customers at https://my.nti-audio.com.

Recall Measurements
The straight-forward but powerful Load Test and Save Test
functions serve the dual purpose of conveniently retrieving
standard test setups for repeat testing and also of saving
stored result data for later recall and examination on screen.
The following measurement functions support the recall function:• SLMeter, sound level meter• FFT Analysis• RT60 Reverberation time• 1/12 Octave Band Analysis• Noise Curves• STIPA, speech intelligibility measurement

203

Data Management

Load Test• Select the memory menu
confirm with enter .

 The memory menu opens.

with the rotary wheel

andSelect File Name
• Select Load Test and confirm with enter.

 The pop-up window Load Test appears.

• Select the project folder and stored data file name with DIR.
• Select LOAD, confirm with enter .

204

Data Management

Append Measurements

View Measurement Data

 The previously stored measurement data is displayed.

The append mode stores the results of several individual measurements into the same data file, thus simplifying measurement result analysis and data handling on the PC.
The following measurement functions support the append
mode:• SLMeter, sound level meter• STIPA, speech intelligibility measurement

Application example:
The sound level LAeq shall be measured at various locations inthe same venue hall using a pink noise test signal. The append
mode allows to store all individual measurement results into
one single data file.
1

The run indication 1 shows the pause symbol.
You may continue with the measurements directly, e.g., choose the measurement function,
setup parameters and press start.

Backup the stored measurement data from the
XL2 to the PC daily. This prevents any data loss
if data has been deleted from the SD Card by
mistake.

205

Data Management

Start the Append Mode
• Select SLMeter and preselect the sound level LAeq.
• Select the memory menu
with the rotary wheel
confirm with enter .

Select Filenameand The memory menu opens.
• Select Start Append Mode and confirm with enter The Start Append Mode window opens.

.

• Name the first part of the file name. The maximum length of
the first part is 12 characters. The next part “_SLM_001” isdefined by the XL2 to avoid overwriting of existing measurements, whereby “SLM” is the appendix for the measurement function and “001” is an automatically-incrementing
number.
• Select START and confirm with enter .

 The append mode is available.
206

Data Management

Take Measurement Results• Measure the sound level LAeq on the first position.
• Select the memory menu and Append Data.

Store Measurement Results

 The pop-up window Append Data appears.
• Select the location ID and measurement ID, thus each measurement result is stored with an individual description forlater documentation.
• Select Append with the rotary wheel
and confirm withenter .

In append mode, the XL2 does not store:• Log files• Wav-files• Repeated report files generated in timer
mode repeat and repeat synchronized.

 The measurement data is stored on the SD Card.
207

Data Management

Append Further Measurement Results• Move to the next location in the room, carry out the measurement and follow the described append data procedure.

Exit Append Mode
• Open the memory menu.
• Select Exit Append after adding the last measurement.

Append After Power Up
You can continue to add measurement results into the samedata file at any time later.
• Store the measurements in the append mode and switch the
XL2 off and on again .

 The pop-up window Continue append appears.

Auto Append
Alternatively the XL2 can append measurement
data to the same report file automatically.
• Start the Append mode and set Auto Append
is ON in the memory menu or in the pop-up
window Start Append Mode.
Skip Append Data
If you select SKIP in the Append Data window,
then no measurement data is appended to thereport file.
• Select Yes and continue adding measurement results to thesame report file in the append mode.
208

Data Management

Recall Previous Measurements for Append
Any previously stored measurement with the remark for append can be recalled and further test records appended.
• Select Load Test and press enter .
• Select the project folder and stored data file name.
• Select LOAD confirm with enter .

 The pop-up window Load for Append appears.

• Select Continue and add further measurements to the same
report file in the append mode.
209

XL2 Projector PRO

13. XL2 Projector PRO Software
The Projector PRO displays the XL2 screen in real-time via
USB on the connected Windows or Mac computer. The software toolbar enables control of the XL2 with the mouse andkeyboard. The background color turns from green to red synchronized with the XL2 limit button color
according to theuser-defined limits.
The “XL View” and the “Sound Level Predictor” display extend
the XL2 Projector PRO for live sound monitoring applications.
• The “XL View” window presents sound levels in large sizeon the connected computer screen. Users may select toview one, two or three sound pressure levels. Exceedinglevels are presented with a pre-warning amber or alarming
red color.
• The “Sound Level Predictor” visualizes the level history of
the current measurement interval and indicates the headroom for the actual measurement period or the next few
minutes. Green bars confirm that the present level is well below limits. Red bars are a call to action to reduce the soundlevel at the mixing desk. This allows the FOH engineer to
optimize dynamic passages of the band for maximum audience satisfaction while still remaining within the legal limits.

210

Additionally, the Projector PRO software offers the ability toretrieve measurement data from the XL2 without interruption
to the measurement process. The entire file system of the XL2
is available while the XL2 is measuring.
The “XL View” and the “Sound Level Predictor” require that
the Projector PRO Option or the Remote Measurement Option
be installed on the XL2.
Projector PRO software is a free download for all registered
XL2 customers on the support website https://my.nti-audio.
com.

Installation Instructions• Register your XL2 and download the software from the support page at https://my.nti-audio.com.
• Unzip the file “XL2 Projector PRO Setup Vxx.zip“ on yourcomputer.
• Start the software installation and follow the instructions
including driver installation.
• Start the XL2 Projector PRO software.
• Start the XL2 Analyzer and connect it to the computer.

XL2 Projector PRO

 The pop-up window USB Mode appears.

• Select COM port on the XL2.
• Microsoft Windows may recognize the new hardware automatically and start the hardware installation assistant. If
prompted, select “No connection to Windows Update” andcontinue with the installation.
• Complete the installation.

 XL2 Projector PRO displays the instrument screen in real-

For more details and features see the XL2 Projector PRO user
manual at ? in the menu.

time.
211

Data Explorer Software

14. Data Explorer (optional)
Data Explorer is a PC-based software application with a powerful data processor for easy and fast analysis of sound levelmeasurement data. It is dedicated to acoustic consultants andnoise measurement professionals. Data Explorer provides aconvenient way to view, analyze and manage data and quickly
create customized reports.

XL2 Data Explorer Permanent
The Data Explorer Option enables the import of logged soundlevel data into the Data Explorer software, a PC-based software application with a powerful data processor for easy andfast analysis of noise monitoring data.

Features of the Data Explorer software:• Data visualization• Fast zoom and pan• Audio playback synchronized to graph• Markers with on-the-fly calculations• Automated tonal and impulsive marker generation• Percentile levels Ln and Rating level Lr calculation• Customized Reporting

Data Explorer 365
An annual subscription service for a XL2 Sound Level Meter isoffered alternatively to the permanently installed option.

Download the Data Explorer software from the XL2 Support
Page https://my.nti-audio.com.

212

Supported operating systems• Windows XP SP3• Windows Vista SP1 or later• Windows 7, 8, 10, 11

Data Explorer Software

213

Building Acoustics

15. Building Acoustics (optional)
The Sound Insulation Reporter software is a PC-based software application that provides all the standard reports for Airborne and Impact sound insulation measurements. Designed
for acoustic consultants, this comprehensive tool uses data
gathered by the XL2 Sound Level Meter, and quickly returns
graphical analysis of all measurement positions.
Additionally, the software offers the ability to acquire real-time
data; two or more XL2 Sound Level Meters, may be controlled
directly by the software. This allows simultaneous wirelessmeasurement in both the sending and receiving room onsite;saving time. To enable this real-time acquisition of data, theSound Insulation Reporter software requires that the connected XL2s also have an activated Remote Measurement Option
installed.
Features:• Airborne, Impact and Facade Sound Insulation• Customized Reporting• Standards ASTM E336, ASTM E413, ASTM E1007, ASTM
E989, ASTM E966, ASTM E1332, BB93, DIN 4109, Document
E, GB/T 19889, ISO 16283, ISO 140, ISO 717, ISO 10140, NEN
5077:2019, SIA 181:2006, SIA 181:2020

214

XL2 Sound Insulation Permanent
The Sound Insulation Option enables the import of measurement data into the Sound Insulation Reporter software.
Sound Insulation Reporter 365
An annual subscription service for a XL2 Sound Level Meter isoffered alternatively to the permanently installed option.
Supported operating systems• Windows Vista SP1 or later• Windows 7, 8.x, 10, 11
Requirements
The measurement of the reverberation time in 1/3 octave band
resolution requires the optional Extended Acoustic Pack installed on the XL2 Sound Level Meter.
Download the software from the XL2 Support Page athttps://my.nti-audio.com.

Building Acoustics

215

Room Acoustics

16. Room Acoustics (optional)
The Room Acoustics Reporter is a PC software for automatically generating reverberation time measurement reports andanalyzing the RTA frequency response spectrum. The software
supports acousticians and experts in the visualization and detailed evaluation of measurement data recorded with the XL2Sound Level Meter.
Features:• Room acoustic simulation according to Sabine or Eyring• Import of own sound absorber database and tolerances• Frequency response spectrum and Noise Curves
The following standards are supported• IEC 61260: Octave-band and fractional-octave-band filters• GB 50371 - Code for sound reinforcement system design• ANSI/ASA S12.2-2019 - Noice criteria curves NC• ANSI/ASA S12.2-2019 - Room noice criterion RNC• DIN 15996:2020 - Grenzkurven GK• ISO R 1996-1971 - Noise rating curves NR• ASR A3.7:2021 - Working Place• DIN 18041: 2016 - Acoustic quality in rooms• ISO 3382-1:2009 - Reverberation time in performance spaces• ISO 3382-2:2008 - Reverberation time in ordinary rooms• ÖNORM B 8115-3:2015 - Room Acoustics
216• ASTM C423-17 - Sound Absorption• ISO 354:2003 - Sound absorption in a reverberation room

XL2 Room Acoustics Permanent
The Room Acoustics Option enables the import of measurement data into the Room Acoustics Reporter software.
Room Acoustics Reporter 365
An annual subscription service for a XL2 Sound Level Meter isoffered alternatively to the permanently installed option.
Supported operating systems• Windows Vista SP1 or later• Windows 7, 8.x, 10, 11
Requirements
The measurement of the reverberation time in 1/3 octave band
resolution requires the optional Extended Acoustic Pack installed on the XL2 Sound Level Meter.
Download the software from the XL2 Support Page athttps://my.nti-audio.com.

Room Acoustics

217

Sound Power

17. Sound Power (optional)
Sound Power Reporter is a PC-based software application thatprovides all the standard reports for sound power measurements in accordance with ISO 3744 and ANSI-ASA S12.54.

XL2 Sound Power Permanent
The Sound Power Option enables the import of measurement
data into the Sound Power Reporter software.

Designed for industrial professionals, this comprehensive tool
uses data gathered by the XL2 Sound Level Meter, and quickly
returns graphical analysis of all measurement positions.

Sound Power Reporter 365
An annual subscription service for a XL2 Sound Level Meter isoffered alternatively to the permanently installed option.

Features of the Sound Power Reporter software:• Visualization of all measurement• Customized Reporting• Standards ISO 3741, ISO 3744, ISO 3746, ANSI-ASA S12.51,
ANSI-ASA S12.54, ANSI-ASA S12.56

Supported operating systems• Windows Vista SP1 or later• Windows 7, 8.x, 10, 11

Download the software from the XL2 Support Page athttps://my.nti-audio.com.

218

Requirements
The measurement of the reverberation time in one-third octave
band resolution requires the optional Extended Acoustic Packinstalled on the XL2 Sound Level Meter.

Sound Power219

NoiseScout

18. Unattended Noise Monitoring
NoiseScout provides a comprehensive but easy-to-use 24/7
noise monitoring solution. Noise levels are recorded on-site by
the XL2 Sound Level Meter and are available for remote monitoring and download. NoiseScout is aimed at both short-term
noise assessments and long-term monitoring applications. It
offers the freedom to start and stop the remote noise monitoring from your office or mobile device providing total flexibility
in meeting your project requirements.
XL2

Noise Monitoring in “Managed Mode”
During acquisition, audio recordings of the loudest periods andautomated email alerts allow noise issues to be addressed before a non-compliance condition arises. NoiseScout displays
the noise levels measured by the XL2 Sound Level Meter livein your web browser. The measurement data recorded out inthe field is presented online in charts and dashboards. Multiple
noise level meters can be monitored simultaneously within themap view, thus providing localized geographic visualization for
all noise levels at a glance. Identified users can access all theirprojects, control their monitors or create basic view modes, allowing stakeholders to oversee their noise level data.

220

Managed Unattended Noise MonitoringNoiseScout

Noise Monitoring in “Gateway Mode”
Direct access to the XL2 Sound Level Meter is available fromaround the world. An internet connection allows SFTP (Secure
File Transfer Protocol) and remote access to the XL2. All data
files can then be retrieved from the remote XL2 Sound Level
Meter even during an ongoing measurement. Also, the spectral data and audio files can be directly downloaded from theremote XL2.
The remote access allows full control of the XL2 Sound Level
Meter. All remote measurement commands available on the
XL2 are supported. For example, the current measurement
data may be captured in real time into a computer application,e.g. C#, MS Excel or LabView. You may program a customized
measurement application for remote sound level monitoring,audio analysis or automated measurement tasks.

Secure FTP Connection

FTP Browser

LAN
Mobile2017-03-16_SLM_000.XL2
2017-03-16_SLM_000_123_Report.txt
2017-03-16_SLM_000_123_Log.txt
2017-03-16_SLM_000_RTA_3rd_Report.txt
2017-03-16_SLM_000_RTA_3rd_Log.txt
2017-03-16_SLM_000_Audio_FS136.0dB(PK)_00.wav

XL2

XL2 Data Explorer
USB

Remote Access to XL2 Sound Level Meter
NoiseScout operates also in a local network (intranet) without
internet connection.

221

NoiseScout

How to connect?
1

The NetBox may be connected to the internet via mobile (3G,
4G, 5G; 4G/5G using an external modem), LAN or Wi-Fi.

Network Status Indication
It replaces the speaker symbol in the top menu.
No network connection

The LAN connection is established automatically. Setup on the
XL2 is required for the 3G mobile and Wi-Fi connection.

Network connection established• Insert SIM card (not provided) into the NetBox• Connect the NetBox to the XL2 Sound Level Meter.
• Select 1 and confirm with enter .

Confirmation check mark indicates successful on-going NoiseScout communication

1

2

222

NoiseScout• Select Settings 2 and confirm with enter .
• Select Mobile Data and confirm with enter ; the minimum
requirement is entering the APN of your provider.

• Confirm Close.

 The XL2 is connected to the network.
• Set the connection parameters and select Exit.

223

NoiseScout

Automated System Self-Test
The measurement microphone of a noise monitor is permanently exposed to the weather. This might impair the microphone capsule and its performance. Therefore, NoiseScout
offers an automated system self-test (CIC). The complete signal chain may be verified periodically, remotely, and without
removing the microphone from site. Thus, precise sound levelmeasurements are ensured. This test also produces an alarmin case of any unexpected issues, like cable or microphone
defects.
The automated system self-test is supported by the XL2Sound Level Meter with the M230 Preamplifier. The microphone preamplifier has a built-in dedicated signal generator
for the self-test, which is activated from NoiseScout via the
XL2 Sound Level Meter through the ASD communication. This
generator produces a square wave signal with the fundamental frequencies 31.25 Hz and 1000 Hz and the corresponding
harmonics for the self-test. The generated test signal spectrum
is measured by the XL2 and stored as a reference. Later on,
NoiseScout repeats the same test, e.g. daily, and the resulting
one-third octave spectrum is compared against the reference.

224

One-Third
Frequency Band[Hz]

Description

Typicalreference spectrum
[dB]

31.5
100
160

fundamental square wave
harmonic
harmonic

102.4
92.4
87.9

200
315
400

harmonic
harmonic
harmonic

84.3
83.1
80.4

500
630
800

harmonic
harmonic
harmonic

80.8
79.3
78.5

1000
3150
5000

fundamental square wave
harmonic
harmonic

101.7
92.3
88.1

6300
8000
10000

harmonic
harmonic
harmonic

84.0
82.6
84.2

12500
16000
20000

harmonics
harmonics
harmonics

81.6
81.7
80.1

NoiseScout

The maximum deviation in each frequency band is specified
at 1 dB supporting the specified range of environmental conditions. Unexpected issues, like cable defects, loose capsulemounting, or a missing microphone capsule cause a higher deviation and trigger an automated alarm.
High ambient noise may affect the self-test. Therefore, theambient noise level is measured prior to performing the selftest. All is fine as long as the ambient noise effect is less than
0.2 dB during the self-test – this requires the ambient noise
to be 13.3 dB below the reference spectrum of the self-test.
High ambient noise levels will be reported in combination witha failed self-test.

The following workflow is carried out by NoiseScout• Measure ambient noise level and compare result with reference spectrum• Generate 31.25 Hz square wave signal and measure actual
noise spectrum• Generate 1000 Hz square wave signal and measure actual
noise spectrum• Compare results with the reference one-third octave spectrum

Self-Test Method
The sysem self-test uses the charge injection
check method, in short CIC. A dedicated squarewave signal is capacitively coupled to the inputof the MA230 Preamplifier and attenuated by
the capacitance of the microphone capsule.
Physical changes in capsules can influence
their capacitance, which ultimately leads to achanged level read from the test signal. The test
signal passes through the preamplifier and thecable to the XL2 Sound Level Meter for evaluation. This allows any changes in the microphonecapacitance, e.g. caused by damages of the microphone capsule or a loose capsule mounting
to be detected.
Additional periodic manual calibration using aSound Calibrator is recommended in combination with a visual inspection of the noise monitor.

This workflow takes approximately 7 seconds.
225

Time Synchronization

19. Time Synchronization
The XL2 Analyzer may synchronize the start time precisely with
the GPS signal. The measurement start matches the GPS timewith an accuracy of +/- 0.7 ms (+/- 32 samples @ 48 kHz).
This requires• a txt-file named “gpssync.txt” stored on the SD card
• a specially adapted GPS Receiver, NTi Audio # 600 000 357
Concept
The measurement start follows these concepts:• Relative TimeThe GPS Receiver generates a square signal with a frequency of 0.1 Hz. The rising edge is exactly synchronized to full
10 seconds. In other words, the positive edge of the signal
indicates the following: 00 – 10 – 20 – 30 – 40 – 50.
The square wave signal is available at the RCA input of the
XL2 Analyzer. The instrument architecture offers two channels, so it can simultaneously process the microphone signal
on the XLR input and the time signal on the RCA input.
Thanks to the GPS signal, the XL2 may precisely start every
10 seconds.
226• Absolute time
The XL2 receives the absolute time from the connected
NetBox, which synchronizes to the NTP service. The XL2time is synced every 60 seconds. The communication between XL2 and NetBox causes an uncertainty in the timing
in the two-digit milliseconds range.
The combination of the relative and absolute timing allows the
XL2 to start the measurement accurately. The GPS time signal
does not have to be permanently present on the XL2 during
the measurement, which accommodates the operation in caseof unfavorable GPS reception. It is important that the time signal was detected by the XL2 at least once before the start ofthe measurement, the XL2 then retains this time information
with an accuracy of typically 0.5 ms per hour.

After repositioning the GPS receiver, the system takes about an hour to initialize for the firsttime.
After rebooting the XL2, or after changing themeasurement function, the XL2 needs to synchronize with GPS time again.

Time Synchronization

XL2 User Interface
The clock delimiter signals the state of GPS time detection.

GPS time signal is synchronized with GPS(locked).
GPS receiver connected, but time signal notsynced with GPS (unlock).
GPS time signal not found, receiver is notconnected or XL2 not configured for GPS.

When starting a GPS time-synchronous measurement you observe the following characteristics:

After starting the measurement, the start
counter in the button will remain at 1 for up
to 10 seconds.

Exactly 4 seconds before a full 10 second
time jump, the button changes and the measured values and the timer value of the previous measurement are reset.
The measurement begins exactly at the
10-second jump.

Start without GPS
If the XL2 has not received a valid GPS information until thestart time, the internal XL2 time will be used as time. The XL2time is set by the NetBox.
If the NetBox has connection to the network before the start
time, then the time of NetBox is precisely synchronized via
NTP. The start is precise to about 10 ms. If the NetBox could
not yet be provided with an exact time by NTP at the start, thenthe NetBox time deviation is approx. 20 ppm since the last synchronization (this corresponds to one error per day of
24 hours * 3600 * 20 / 1e6 = 1.7 sec.
As soon as the XL2 receives a valid time information via GPS,the time deviation is logged in the log file.

227

Time Synchronization

Minutes of deviation
The deviation of the time currently used for the measurement from the GPS time is recorded by the XL2 in the log file
(123_Log.txt).

Add_To_Time[ms]

GPS Status
[]

0.0

2.0

ExampleThe PPS signal is recorded with the XL2. For this, the input of
the XL2 from XLR to RCA can be set. The positive edge of therecording should always be exactly to multiples of 10 seconds,
but in this case at 00: 35: 00,005:

Meaning of the column “GPS Status”:
0.0

No GPS signal detected at the RCA input

1.0

GPS signal detected but signaled UNLOCKED

2.0

GPS signal LOCKED (OK)The deviation Add_To_Time can only be determined currently
if the GPS status = 2 (locked). Otherwise, the last known error is used for the current log line. The Add_To_Time column
indicates “-.-” in case that there was no GPS time recognizedsince the start of the device.
228_123_log.txt:
2017-10-05 09:49:58 00:34:58 -5.00 2.0 ---/--2017-10-05 09:49:59 00:34:59 -5.00 2.0 ---/--2017-10-05 09:50:00 00:35:00 -5.00 2.0 ---/--2017-10-05 09:50:01 00:35:01 -5.00 2.0 ---/--2017-10-05 09:50:02 00:35:02 -5.00 2.0 ---/--In the log file, a correction value Add_to_Time of -5ms is recorded for this time position, so the corrected position of thepulse is: 00: 35: 00,005 + (-5ms) = 00:35:00.
The state of the time synchronization can be seen in detail on
the NoiseScout Gateway website.

Time Synchronization

Connection Diagram

GPS Receiverconnects to XL2Adapter Cable MD6/RCA

Adapter Cable MD6/USB

connects to NetBox - USB 1

229

Remote Measurement

20. Remote Measurement
The Remote Measurement option allows the real-time acquisition of XL2 measurement data directly into a computer application via USB. The option adds a real-time acquisition facility to
the Sound Insulation Reporter software.
Alternatively you can write your own unique measurement applications for sound level monitoring or automated measurements, e.g. with MS Excel or LabView. A documented command set for data retrieval via USB is available. The following
XL2 measurement functions are supported:• Sound level meter and spectrum analyzer SLMeter/RTA• Vibration Meter VibMeter• FFT Analyzer + Tol• RT60 reverberation time
• Audio analyzer RMS/THD+N• High-resolution RTA function 1/12 Oct + Tol
The functionality of the Projector PRO option is included.

Order information:
Remote Measurement Option
NTi Audio #: 600 000 375

230

The commands are sent in ASCII format through the virtualCOM port to the XL2 Analyzer.
Example Command Set
INIT START
MEAS:INIT
MEAS:SLM:123? LAF
Result returned to PC: 53.8 dB,OK

The time the XL2 requires for a response depends on the command and the workload of the XL2 (logging settings). A typical
pattern for querying measurement data is:
xl2.write(‹MEAS:INIT\n›)xl2.write(‹MEAS:SLM:RTA:dt? EQ\n›)result = xl2.readline()
This pattern delivers a measurement result within:• Min:
8 ms• Mean: 10 ms• Max: 35 ms

For more details you may download the dedicated Remote
Measurement Reference Manual.

Remote Measurement

Auto Start
The XL2 with serial number ending “E0” or higher may poweron automatically upon after a power loss (e.g. mains power disconnected or battery pack empty) the power is available again.
Best the instrument is operated by mains power without theinternal battery pack installed. This auto start functionality isenabled by copying a txt-file with the file name “AutoOn.txt”
onto the SD Card. This allows to remotely control the XL2 assoon as power supply is available at the instrument.

231

Microphones

21. Microphones
Overview Measurement Microphones

232

M2230

M2340

M2211

M2215

M4261

Certified Class 1
measurement
microphonein accordance withIEC 61672,
metal diaphragm

Certified Class 1
measurement microphone according toIEC 61672, metal diaphragm, system selftest (CIC) with XL2General purpose
measurement
microphoneclass 1 frequency
response,
metal diaphragm

Measurement microphone for high soundlevels (up to 153 dB),class 1 frequency
response, metal diaphragm

Cost-effectiveclass 2 measurement
microphone for general sound level testingand service of audioacoustic installations

consists of MA220
PreAmplifier andMC230 or MC230A
capsuleconsists of
MA230 PreAmplifierand MC230A capsuleconsists of
MA220 PreAmplifierand 7052 capsuleconsists of
MA220 PreAmplifierand 7056 capsulewith permanentlyinstalled capsuleMicrophones

Overview Outdoor Measurement Microphones

M2230-WP
Outdoor Microphone

M2340-WP
Outdoor Microphone

M4261-WP
Outdoor Microphone

Certified outdoor measurement
microphone,class 1 in accordance with IEC 61672

Certified outdoor measurement
microphone,class 1 in accordance with IEC 61672,
system self-test (CIC) with XL2Outdoor measurement microphone,class 2 in accordance with IEC 61672

consists of
M2230 Measurement Microphone+ WP30 Weather Protection

consists of
M2340 Measurement Microphone+ WP30 Weather Protection

consists ofM4261 Measurement Microphone+ WP61 Weather Protection

233Microphones234

Microphones

Overview Microphone Preamplifier
MA220
PreAmplifier

The plug-on measurement microphones combined with the
XL2 Analyzer create a powerful sound level meter and a professional acoustic analyzer.MA230
The microphones are 48 VDC phantom-powered and include
PreAmplifier
an electronic data sheet.

Integrated Preamplifier
The microphone body contains a preamplifier that requires
48 VDC phantom power supply for operation. The microphones
combine high dynamic range and wide frequency range with
low noise. They can also be connected to the XL2 Audio andAcoustic Analyzer using an ASD Cable for measurements at
remote locations or for reduction of acoustic reflections.
Microphone preamplifiercompatible with 1/2” pre-polarized capsules

Microphone preamplifiercompatible with 1/2” pre-polarized capsules,
system self-test (CIC) with XL2235

Microphones

Electronic Data Sheet
The microphones include an electronic data sheet. The Automated Sensor Detection (ASD) of the XL2 Analyzer reads thisdata, i.e. the microphone model and calibration data. This promotes faster setup and ensures accurate measurements.
Screen connection used for
ASD technology
XLR M
Pin 2 +Pin 3 Pin 1 Shield

2

2

3

3

1

1

Microphone
2
3
1

ASD

Microphone
Capsule

Pin 1
Pin 2
Pin 3

XLR M

Connection diagram of measurement microphones
with electronic data sheet

Microphone plugs directly into the XL2
The XL2 automatically reads the electronic data sheet of theconnected microphone as follows:• Connect the measurement microphone to the XL2.
• Switch on the XL2.

 The XL2 reads the electronic data sheet of the connected
microphone during a brief initialization process prior to thefirst measurement.

236

Microphone Connection via the ASD Cable
The NTi Audio measurement microphones can be connectedto the XL2 Analyzer using an ASD Cable for measurements
at remote locations or for reducing acoustic reflections. The
electronic data sheet is transmitted via the XLR connector’s
housing. Do not touch this during the brief initialization period
to ensure the complete data sheet is recognized by the XL2.
The automated sensor detection does not disturb any measurements. You may join 5 or 10 meter ASD Cables together inseries. The ASD technology supports accurate data communication up to a combined cable length of 20 meters (= 65 feet).

Microphones

Microphone Connection via a professional Audio Cable
For distances longer than 20 meter (= 65 feet) use a highquality, low-capacitance standard professional audio cable. The
microphone sensitivity has to be entered manually into the XL2Analyzer.
Alternatively connect the microphone first directly to the Analyzer. The XL2 reads the sensitivity and remembers this value.
Afterwards connect the audio cable.

• Use the microphone for the intended
purpose only.
• Protect the microphone from contaminationby always using the supplied windscreen.
• Never use the microphone in a damp or wet
environment.
• Do not jar or drop the microphone.
• Do not remove the microphone protective grid.
• Do not touch the microphone membrane.
• Remove the black dust cap of the 1/2”
measurement microphones prior to use.
• In an outdoor environment, ensure that you
install protection against lightning strikes.

237

Microphones

Outdoor Measurement Microphones
The Outdoor Measurement Microphones offer a weather-protected measurement solution for the XL2 Sound Level Meter
allowing acquisition of environmental noise data in outdoor applications. The corrosion-free polymer housing, wind screen,water-repellent membrane and bird spike provide excellent protection from rain, wind, dust and perching birds.

Inside:Protection Cage withwater-repellent
membrane
WP30 #600 040 064
WP61 #600 040 081

Outdoor Measurement Microphone Types• M2230-WP: M2230 Measurement Microphone +WP30 Weather Protection• M2340-WP: M2340 + WP30 Weather Protection• M4261-WP: M4261 + WP61 Weather Protection

Inside:Measurement
Microphone• Do not install the Outdoor Measurement Microphones in horizontal direction. Raindrops
may damage the measurement microphone.
• The snap mechanism works only at temperatures above -15°C / 5°F (as the O-Ring stiffens). In colder conditions we suggest you
warm up the housing first, e.g. with yourhands.

238

Fixing Screw
M5 x 6 mm

Bird Spike BS01#600 040 062

90 mm
Wind Screen#600 040 061
Upper
Body Part#150 000 048
Lower
Body Part#150 000 047

O-Ring Replacement Set#600 040 069

TripodMounting Plate#600 040 072

Microphones

The Outdoor Measurement Microphones M2230-WP and
M2340-WP fulfill the Class 1 requirements according toIEC 61672 and ANSI S1.4 for vertical sound incidence. For compliance with horizontal sound incidence a spectral correction is
employed in the associated XL2 Sound Level Meter.

Always activate the applicable frequency correction filter in the XL2. The filter ensuresthat the measurements accuracy meets theclass 1 requirements of IEC 61672 andANSI S1.4.

Alternatively the Measurement Microphone M2211 or M2215
can be fitted into the Weather Protection WP30. These microphones have to be pushed further into the upper body by 3
mm. The top part of the capsule has to be 13 mm above theupper body housing of the WP30. This is required because theM2211 and M2215 capsule is 3 mm shorter than the default
M2230 microphone capsule.
The Outdoor Measurement Microphone M4261-WP fulfills theClass 2 requirements according to IEC 61672 and ANSI S1.4.
It consists of an M4261 Microphone and the WP61 Weather
Protection. For compliance with horizontal sound incidence a
spectral correction is employed in the associated XL2 Sound
Level Meter.

239

Microphones

Assembling
This chapter describes how to install the Measurement Microphone into the weather protection kit:
Install ASD Cable• Feed the female XLR of the ASD Cable through the bottomof the lower body tube.
• Attach the footer plate to the lower body tube using thethree allen screws, feeding the cable through the side slotof the footer plate.

Insert Measurement Microphone• Connect the measurement microphone to the female XLRof the ASD Cable.
• Insert the measurement microphone into the upper bodytube so that the bottom end of the microphone is in linewith the bottom end of the upper body tube. Align the fixing
screw hole of the upper body tube with the lower screw ofthe measurement microphone (remove the fixing screw to
see the lower screw head through the fixing screw hole).

Fixing Screw Hole

Lower screw ofmeasurement
microphone240

Microphones

Attach the Microphone to the Upper Body Tube
Attaching the fixing screw of the upper body tube onto thelower screw of the measurement microphone ensures that the
microphone housing is not scratched.

Assemble the Weather Protection Body
Retract the ASD cable through the lower body tube and screw
the lower body tube to the upper tube, ensuring that the cable
does not twist during this operation.

• Insert and gently tighten the fixing screw while jiggling the
microphone. You will feel the fixing screw center in the headof the lower screw of the microphone. Do not over tighten
the fixing screw.
• Again verify that the bottom end of the inserted microphone isin line with the bottom end of the upper body tube.

In Line241

Microphones

Mount the Top Section
The top section of the weather protection kit consists of thewind screen, the enclosed protection cage with water-repellent membrane and the bird spike. Gently slide the top section
over the microphone tip and on to the upper body tube. You will
feel a slight increase in resistance approximately 3 mm before
the top section’s final position. Slightly increase the pressure
until the top section snaps into the final position with an audible click.

 You have successfully assembled the Outdoor Measurement Microphone.
242

Calibration
The design of the Outdoor Measurement Microphone supports easy calibration of the microphone. To calibrate, follow
the procedure below:• The top section of the Outdoor Microphone is snappedon to the body tube. Remove the top section of the Outdoor Microphone by gently pulling the bird spike upwards.
At the same time gently push up on the cage inside thewind screen with two fingers of your other hand. You will
feel when the snap mechanism is released.
Gently remove the top section.
Pull

Push

Microphones• Calibrate the microphone as described in the XL2 user manual using the NTi Audio Precision Calibrator.

• The outdoor windscreen is recommended
to be replaced annually. The “WP30/WP61
Windscreen Replacement” includes twospare windscreens, NTi Audio # 600 040 061.
• The water-repellent membrane in the top section is mounted with two O-Rings. Inspectthese O-Rings (13x1 mm) and the membraneannually for proper seating and good condition. Do not touch the water-repellent membrane.

• Snap the top section back into position on the body tube.

 You have successfully calibrated the Outdoor Measurement Microphone.
243Microphones

Disassembling the Top Section

Capsule Replacement Instruction• The top section is snapped on to the body tube. Remove
the top section by gently pulling the bird spike upwards. At
the same time gently push up on the cage inside the windscreen with two fingers of your other hand. You will feel
when the snap mechanism is released.
• Gently remove the top section and turn the top section upside down and hold it by the bird spike.
• Gently unscrew the cage from the hole of the wind screen.
Do not touch the water-repellent membrane!
• Assemble in reverse order.

The microphones for the XL2 Analyzer include an electronic
data sheet. The Automated Sensor Detection (ASD) of the XL2Analyzer automatically reads this data, i.e. the microphonemodel and calibration data. This promotes faster setup and ensures accurate measurements. In case of a capsule replacement, the electronic data sheet needs to be updated with thedata of the new capsule.

244

Step-by-Step-Instruction• Install the new capsule on the microphone preamplifier.
• Plug the measurement microphone directly into the XL2.
• Install the latest firmware in the XL2, available athttps://my.nti-audio.com/support/xl2.
• Start the XL2 Projector PRO Software. The computer requires online connection to the web.
• Connect the XL2 with the USB cable to the Projector PRO
software, thus you see the XL2 display live on the computer
monitor. (if prompted select COM-Port on the XL2)
• Press the computer keyboard keys “Ctrl + Shift + F5” at thesame time (alternatively “Ctrl + Alt + F5”)

Microphones• Select Original NTi Audio Microphone or Custom microphone.
• Case: Original NTi Audio Microphone- Enter the serial number of the new capsule- Confirm by clicking Write to MA220.
- Now XL2 reads the factory sensitivity of the new capsulefrom the NTi Audio server and stores the new data into
the electronic data sheet of the preamplifier. You will beprompted if all is in good order.
• Case: Custom microphone- Enter the microphone sensitivity- Confirm by clicking Write to MA220.
- Now XL2 stores the microphone sensitivity as factory sensitivity in the electronic data sheet of the MA220 PreAmplifier.
• Verify the setting in the “CALIBRATE” screen of the XL2 andperform a user calibration to verify if the new capsule works
in good order.

245

Further Information

246

Further Information

22. Further Information
My NTi Audio
Register your instruments at My NTi Audio and benefit fromthe following possibilities:• Free updates for your instruments• Activation of optional product functions• Premium access to downloads• Receive application and product news
• Faster worldwide support• Tracing support in case of loss or theft• Calibration support
How to Register• Open the web page “https://my.nti-audio.com”.
• You are prompted to login or create your My NTi Audio
account.
• The web page “My NTi Audio Products” opens.
• Select the product type and enter the serial number.
• Confirm with “Register”.
• Now your product is listed in the table “My Products“.

Tips and Troubleshooting
Overview• Resetting to Factory Default• XL2 Starts Up with Limited Functions• Can I use another SD Card?
• Formatting the SD Card
• SD Card Errors• Error messages on display• Stored Data or Wav-files not available on SD Card
• Date and Time Lost

Resetting to Factory Default
If the XL2 Audio and Acoustic Analyzer reacts unexpectedly, areset to the factory settings might solve the problem.
• Switch off the XL2• Hold down escape.

.
and simultaneously operate On/Off The XL2 starts up and the reset confirmation is displayed.

 Congratulations, your NTi Audio product is registered247

Further Information

XL2 Starts Up with Limited Functions
The XL2 has been operated the last time in one of the simplified application profiles and the system settings have beenchanged as follows: Select Profile from Yes to No.

SD Card Errors
The XL2 Audio and Acoustic Analyzer writes measurement
data automatically onto the SD Card during ongoing measurements, thus a functioning SD Card has to be inserted at all
times.

• Follow the above resetting to factory default.

 The XL2 will start up with full functionality.

Error Messages
Missing SD-Card

Can I use another SD Card?
Yes, you can use any alternative SD Card, such as offered in thechapter Further Information: Accessories.
• Switch off the XL2 .
• Insert the SD Card into the XL2 Analyzer.
• Switch on the XL2 .

 The XL2 writes the data structure automatically to the in-

Actions to do
Insert the SD Card.

SD-Card is not FAT Format the SD Card on the PC. Follow
formatted
the instructions at Formatting the SC
Card in this chapter.
SD-Card is full

The memory of the SD Card is full.
Download all data to the PC and empty the SD Card.

serted SD Card.

Formatting the SD Card
In case you need to format the SD Card, then we recommend
doing so utilizing the software SDFormatter. This software ensures the best performance of your SD Card. SDFormatter is afree download at www.sdcard.org/downloads.
248

Other Error Messages on Display
In case error messages, such as Error 900, Error 901, ..., isshown on the XL2 display , then follow “Resetting to Factory
Default” in this chapter. These error messages describe a common status information and are not associated with a dedicated issue. If such errors occur frequently, then kindly report thefull error message back to NTi Audio for resolution. Thank you.

Further Information

Stored Data or Wav-files not available on SD Card
The file system might be corrupted.
• On the PC, right-click on the “NTi Audio XL2” drive, select“Properties” and click “Check Now” as shown below.
• Thereafter all stored data should be available again.

Date and Time Lost
The XL2 Analyzer has a small internal battery installed. Thispowers the real time clock (RTC), and ensures the accurate
display of the date and time on the instrument and in the measurement reports, even if the device has been powered down
for a period of time. This, so called, RTC battery is soldered on
to the internal circuit board. The typical battery lifetime is 8-9
years.
Kindly return the instrument for service. For convenience, thisservice may be combined with the recommended annual calibration of the XL2 Sound Level Meter.

249

Further Information

Firmware Update
You will find information about the installed firmware version in the systems settings of the instrument. The firmware revision history is listed on the XL2 Support Page
https://my.nti-audio.com.
Updating the firmware on the XL2 is executed by placing the
XL2Vxxx.xx file in the root directory of the XL2. When started,
the XL2 automatically completes the firmware update.

1

1

250

XL2.htm
This file opens the XL2 instrument status page, for online• Firmware updates• Activation of options

Firmware update with XL2 in hand, PC online:• Start the XL2 and connect it to the PC.
• The XL2 displays the pop-up window USB Mode.
• Select Mass storage. The PC thus recognizes the XL2 as amass storage device.
• Double-click the file XL2.htm 1 . The web screen “XL2 Instrument Status“ opens.
• Select “Look for FW Updates“. The web screen “XL2 Support Page“ opens.
• Compare the firmware version to the latest version available.
• If an update is required, download and save the firmware
file XL2Vxxx.xx into the XL2 root directory (the root directory shows the folders “Projects”, XL2_SYS”, the file“xl2.htm” and others).
• Remove the USB cable and power up the XL2 .
• Watch the display and wait until the update is finished.
• All settings are back to factory default. Adjust the display andreporting settings according your requirements.

No PC available
If you have no web access at all, please contact the local NTi
Audio partner.

Further Information

Options
The System menu shows the installed options on the XL2.
The following options extend the measurement functions of
the XL2:
Extended Acoustic Pack
NTi Audio #: 600 000 339
The Extended Acoustic Pack offers the following additional features for sound level- and acoustic measurements.
• SLMeter/RTA function- Recording of linear wav-files (24 bit, 48 kHz)- Percentiles for wide band and spectrum with flexible setting from 0.1% to 99.9%- Sound Exposure Level LAE- 100 ms logging- RTA logging of Lmin and Lmax
- Event-triggered audio and data recording- Time weighting: Impulse (LxI, LxIeq with x= A, C, Z)- True peak level in 1/1 and 1/3 octave resolution- Clock-impulse maximum level (TaktMax) in accordancewith DIN 45645-1 and DIN 45657- Impulsiveness detection in accordance with BS4142:2014
and NordTest ACOU 112• FFT function- High-resolution Zoom-FFT with selectable frequency
ranges and resolution up to 0.4 Hz in the range of 5 Hz to
20 kHz- Recording of linear wav-files (24 bit, 48 kHz)• RT60 function- Reverberation time in 1/3 octave resolution• 1/12 octave Spectral Analyzer(requires Spectral Limits Option)- Recording of linear wav-files (24 bit, 48 kHz)

Projector PRO Option
NTi Audio #: 600 000 439
The Projector PRO option enables the following two additional
functions to the Projector PRO software:• “XL View” for large screen dB level display• “Sound Level Predictor” that indicates the headroom for the
next few minutes during live sound mixing

251

Further Information

Speech Intelligibility STIPA
NTi Audio #: 600 000 338

Remote Measurement Option
NTi Audio #: 600 000 375

The XL2 Analyzer measures the speech intelligibility according to the latest revision of standard IEC 60268-16:2020(edition 5) and older editions. It includes ambient noise correction and automated averaging of measurements. The XL2
displays the measurement results as STI or as CIS results, accompanied by the individual levels and modulation indices ofthe seven octave bands.

The Remote Measurement option allows the real-time acquisition of XL2 measurement data directly into a computer application via USB. The option adds a real-time acquisition facility to
the Sound Insulation Reporter software.

The measurement results are acquired from the dedicated
STIPA test signal source:• NTi Audio TalkBox, acoustic signal generator
required for audio systems with voice microphones, thus
measuring the complete signal chain• Minirator MR-PRO, test signal generator
required for audio systems with line inputs• Other Audio Players
Register the XL2 and download the STIPA test signal athttps://my.nti-audio.com/support/xl2

252

Alternatively you can write your own unique measurement applications for sound level monitoring or automated measurements, e.g. with MS Excel or LabView. A documented command set for data retrieval via USB is available. The following
XL2 measurement functions are supported:• Sound level meter and spectrum analyzer SLMeter/RTA• Vibration Meter VibMeter• FFT Analyzer + Tol• RT60 Reverberation time
• Audio analyzer RMS/THD+N• High-resolution RTA function 1/12 Oct + Tol
The Remote Measurement Option includes the functionality
available in the Projector PRO option.

Further Information

Spectral Limits Option
NTi Audio #: 600 000 376
The Spectral Limits Option extends the XL2 function range inboth, the sound and vibration mode. It adds noise curves, trace
capturing, relative curve display and comprehensive tolerance
handling for the FFT Analysis and high-resolution spectral analysis up to 1/12th octave. The vibration mode is enabled upon
installing the vibration option.

• FFT and 1/12 octave Analyzer- Capturing of multiple readings into the internal memory- Comparing measurement results against captures withrelative or absolute curve display- Comprehensive tolerance handling with tolerance masks
based on captures for passed/failed measurements• 1/12 octave Spectral Analyzer- High-resolution spectral analyzer 1/12 Oct + Tol- Selectable 1/1, 1/3, 1/6 and 1/12 octave resolution- Frequency band listening at rear speaker- Sound Mode: 11.5 Hz to 21.8 kHz- Vibration mode: 0.73 Hz to 1.36 kHz• FFT Analyzer
High-resolution Zoom-FFT with selectable frequency ranges
and resolution up to 0.4 Hz in the range of- Sound mode: 5 Hz to 20 kHz- Vibration mode: 1 Hz to 20 kHz• Sound Level Meter
True peak level in 1/1 and 1/3 octave resolution (disabled with
type approved firmware)• Noise Curves
In accordance with ANSI S12.2-2019, -1995 and ISO 1996

253

Further Information

Type Approval Option
NTi Audio #: 600 000 377

XL2 Vibration Option
NTi Audio #: 600 000 436

The Type Approval Option upgrades the instrument to the
XL2-TA, the sound level meter dedicated to certified measurements. The XL2-TA with the M2230 microphone formsa type approved sound level meter offering class 1 performance in accordance with IEC61672, IEC61260 and
ANSI S1.4.
The Type Approval Option includes• XL2-TA Firmware V4.71 (approved Firmware)• Sticker XL2-TA• XL2-TA Manual (available online at www.nti-audio.com/XL2)

The Vibration Option turns the XL2 Analyzer into a professional
vibration meter with broadband measurements and spectral
analysis in 1/3 or octave resolution. The XL2 Vibration Meter
determines vibration acceleration, velocity and deflection withstandard-compliant weighting filters in the frequency range
from 0.8 Hz to 2.5 kHz. Detailed recording of measurement
data and audio files allow for comprehensive evaluation andreporting. In addition, the XL2 Vibration Meter comes standard
with an FFT analysis and an oscilloscope function. Selectable
FFT frequency ranges from 1 Hz to 1.69 kHz allow a detailed
examination of the measured vibrations.

How do I get my XL2-TA ready for accreditation?
• Install the Type Approval Option on the XL2 and apply the
XL2-TA sticker on top of the XL2 label on the display.
• Download the dedicated firmware for accreditation to yourXL2 from the XL2 Support Page at https://my.nti-audio.com.
• After the firmware installation, the XL2-TA starts with a popup window “XL2 Type Approved SLM/RTA“.The sound level
meter function SLM/RTA may be accredited now.

The Spectral Limits Option adds functions to the Vibration Meter including a zoom FFT up to 20 kHz and a 1/12 octave band
analysis from 0.73 Hz to 1.36 kHz. Also, it adds the ability torecord reference spectra and set tolerances for pass / fail quality control measurements. The Remote Measurement Option
allows the real-time acquisition of measurement data directly
into a computer application via the USB interface. A documented command set is available.

The type approved firmware deactivates the X-Curve in the
SLM function and the unit SPL in the RMS/THD+N function.

The Vibration Option is supported by the XL2 with firmware
V4.11 or higher.

254

Further Information

Cinema Meter Option
NTi Audio #: 600 000 379
The Cinema Meter Option forms the dedicated solution
for efficient calibration and repetitive verification of cinema
loudspeaker systems according to the SMPTE ST 202:2010,
SMPTE RP 200:2012 and ISO 2969:2015 standards. An interactive assistant guides the user through dedicated measurement
procedures.

• Create new cinema
Generates measurement templates according the cinema
size with dedicated X-curve selection.
• Calibrate cinema
Calibration menu for reference data recording of each channel as well as headroom tests and averaging measurement
results of different microphone positions• Verify Cinema
Verification menu for periodical cinema measurements andcomparison against the reference data
• Lock into Verify Mode
Locks the XL2 Analyzer in the Verify Cinema mode. After
powering off the instruments starts up directly in the Verify
Mode again. The user may unlock the instrument anytime.
• View verification results
Displays measurement deviations of periodical measurement against reference data.
• ExitReturns back to other XL2 measurement functions.
The Cinema Meter Option consists of• Spectral Limits Option
NTi Audio # 600 000 376• Cinema Assistant Option
NTi Audio # 600 000 378

255

Further Information

XL2 Data Explorer Option
NTi Audio #: 600 000 430

XL2 Sound Insulation Option
NTi Audio #: 600 000 432

The Data Explorer Option enables the import of logged soundlevel data into the Data Explorer software, a PC-based software application with a powerful data processor for easy andfast analysis of noise monitoring data.

The Sound Insulation Option enables the import of measurement data into the Sound Insulation Reporter software.

Visualize, analyze and control millions of data points with thistool that is dedicated to acoustic consultants and noise measurement professionals. It provides a convenient way to view
and manage your data and quickly create customized reports.

Sound Insulation Reporter is a PC-based software applicationthat provides all the standard reports for Airborne, Impact andFacade sound insulation measurements. Designed for acoustic consultants, this comprehensive tool uses data gatheredby the XL2 Sound Level Meter, and quickly returns graphicalanalysis of all measurement positions.

Features of the XL2 Data Explorer software:• Data visualization• Fast zoom and pan• Audio playback synchronized to graph• Markers with on-the-fly calculations• Automated tonal and impulsive marker generation• Percentile levels Ln and Rating level Lr calculation• Customized Reporting

Features of the Sound Insulation Reporter software:• Airborne, Impact and Facade Sound Insulation• Visualization of all measurement data
• Customized Reporting• Standards ASTM E336, ASTM E413, ASTM E1007, ASTM
E989, ASTM E966, ASTM E1332, BB93, DIN 4109, Document E, GB/T 19889, ISO 16283, ISO 140, ISO 717, ISO
10140, NEN 5077:2019, SIA 181:2006, SIA 181:2020

Data Explorer 365
NTi Audio #: 600 000 431
Annual subscription service for one XL2 Sound Level Meter.

Sound Insulation Reporter 365
NTi Audio #: 600 000 433
Annual subscription service for one XL2 Sound Level Meter.

256

Further Information

XL2 Room Acoustics Option
NTi Audio #: 600 000 440
The Room Acoustics Option enables the import of measurement data into the Room Acoustics Reporter software.
The Room Acoustics Reporter is a PC software for automatically generating reverberation time measurement reports andanalyzing the RTA frequency response spectrum. The software
supports acousticians and experts in the visualization and detailed evaluation of measurement data recorded with the XL2Sound Level Meter.
Features:• Room acoustic simulation according to Sabine or Eyring• Import of own sound absorber database and tolerances• Frequency response spectrum and Noise Curves

The following standards are supported• IEC 61260: Octave-band and fractional-octave-band filters• GB 50371 - Code for sound reinforcement system design• ANSI/ASA S12.2-2019 - Noice criteria curves NC• ANSI/ASA S12.2-2019 - Room noice criterion RNC• DIN 15996:2020 - Grenzkurven GK• ISO R 1996-1971 - Noise rating curves NR• ASR A3.7:2021 - Working Place• DIN 18041: 2016 - Acoustic quality in rooms• ISO 3382-1:2009 - Reverberation time in performance spaces• ISO 3382-2:2008 - Reverberation time in ordinary rooms• ÖNORM B 8115-3:2015 - Room Acoustics• ASTM C423-17 - Sound Absorption• ISO 354:2003 - Sound absorption in a reverberation room

Room Acoustics Reporter 365
NTi Audio #: 600 000 441
Annual subscription service for one XL2 Sound Level Meter.

257

Further Information

XL2 Sound Power Option
NTi Audio #: 600 000 434
The Sound Power Option enables the import of measurement
data into the Sound Power Reporter software.
Sound Power Reporter is a PC-based software application thatprovides all the standard reports for sound power measurements. Designed for industrial professionals, this comprehensive tool uses data gathered by the XL2 Sound Level Meter,and quickly returns graphical analysis of all measurement positions.
Features of the Sound Power Reporter software:• Visualization of all measurement• Customized Reporting• Standards ISO 3741, ISO 3744, ISO 3746, ANSI-ASA S12.51,
S12.54, S12.56

Sound Power Reporter 365
NTi Audio #: 600 000 435
Annual subscription service for one XL2 Sound Level Meter.

258

Further Information

259

Further Information

Installation of Options
1.

7.
2.
Power On XL2

3.

PC
Insert License number

Mass storage

6.
4.

5.

9.

1.

Open XL2-TA.htm

260

Activate option
Login
Download activation file and copy
to XL2 (xx_0xxxx.txt)(https://my.nti-audio.com)

Further Information

Accessories
Manufacturer Calibration Certificate
The calibration certificate lists the individual product data with serial number. The
8.
calibration
and adjustment procedures
follow the documentation and traceability
requirements of the EN ISO / IEC 17025
standard. Annual re-calibration of the instrument is recommended ensuring acGet Activation Keycurate measurements.
NTi Audio # 600 000 018
Calibration
Certificate

Ever-ready PouchThe Ever-ready Pouch protects the XL2during transport and operation. With its
convenient belt-clip, the XL2 can be kept
close-by for those tasks requiring both
hands. The Ever-ready Pouch allows operation of the XL2 while fitted in the pouch.
NTi Audio #: 600 000 335

Mains Power Adapter
Mains Power Adapter the XL2 Audio andAcoustic Analyzer with removable plug
types. The Mains Power Adapter suits the
typical power sockets in Australia, China,
Europe, Japan, US and UK.
NTi Audio #: 600 000 333
Spare Li-Po Battery
Rechargeable spare battery for portablemeasurements at any time.
NTi Audio #: 600 000 337
ICP Adapter ASD
The ICP Adapter connects to the XL2 andgenerates ICP power supply for accelerometers and other custom sensors. The
adapter offers an electronic data sheet,
which stores the sensitivity and individualserial number of the connected sensor.
NTi Audio #: 600 010 223
ICP is a registered trademark of PCB Piezotronics.

10.

261

Further InformationXLR Adapter ASD
XLR male/female Adapter with electronic
data sheet for automated sensor detection (ASD) of other sensors. The adapter isavailable in two variations: The type ASD2 is used for measurement microphones
with isolated housing ground connection
and the type ASD for induction loop andother sensors.

Battery Charger
The Battery Charger efficiently recharges
the spare battery whilst you are using
your XL2 Audio and Acoustic Analyzer.
One spare Li-Po battery is included withthe battery charger.
NTi Audio #: 600 000 332

NTi Audio #:• XLR Adapter ASD: 600 000 383• XLR Adapter ASD-2: 600 000 385

XL2 Mounting Adapter
This mechanical adapter piece mounts
the XL2 on a microphone stand. Adaptersfor 3/8” or 5/8” stands are included.
NTi Audio #: 600 000 372

Exel System Case
This compact system case provides theprofessional transport protection for workin the field. It offers space for the handheld instruments, cables and connectors.
NTi Audio #: 600 000 334

Ball Head Mount
This flexible universal joint mounts the
XL2 on a 1/4” or 3/8” stand. It provides
the facility to mount the XL2 at any angle.
NTi Audio #: 600 000 387
A 5/8” stand requires additionally the
Mounting Adapter, # 600 000 372.

262

Further Information

I/O

Digital I/O Adapter PCB
The Digital I/O Adapter serves to control
external peripheral devices, such as indicating sound levels that exceed limits on
a big external red-orange-green lamp. It
connects to the digital I/O interface.
NTi Audio #: 600 000 380
XL2 Input Keypad
The XL2 Input Keypad offers four marker
keys to trigger an event recording or categorize any noise during measurements.
Requires the optional Extended Acoustic
Pack.
NTi Audio #: 600 000 384

ASD Cable
The ASD Cable allows for extended connections of the NTi Audio measurement
microphones. It supports the transfer ofthe electronic data sheet from the microphone to the XL2 Analyzer.
NTi Audio #:• 5 meter (16 foot): 600 000 336• 10 meter (32 foot): 600 000 364• 20 meter (64 foot): 600 000 365
The ASD technology for the electronic
data sheet transfer is applicable for a cable length of up to 20 meters (64 feet).

263

Further Information

STARQUAD cablewith low capacitive load
1

1

2

2

3

3
ASD

Housing

do not connect

Housing

Capacity between ASD line to shield total < 2.7nF

ASD Flat Ribbon Cable 1m
Microphone cable for passing closed windows or doors. It supports the transfer ofthe electronic data sheet from the microphone to the XL2 Analyzer.
NTi Audio #: 600 000 367

264

NetBoxThe NetBox connects the XL2 Sound
Level Meter to the internet for unattended noise monitoring. It transfers themeasurement data to the fully-managed
NoiseScout Web Portal in real time orprovides a secure internet FTP access tothe instrument. The noise monitor may
be connected via 3G, 4G, 5G, LAN or
Wi-Fi (an external modem is required for
4G/5G).
NTi Audio #:• NetBox (LAN & Wi-Fi): 600 000 450• NetBox with 3G-Modem, LAN & Wi-Fi:
600 000 458• NoiseScout 365(subscription service for one year)
or Data Credits- 30 Days: 600 000 490- 100 Days: 600 000 491- 366 Days: 600 000 492- 1096 Days: 600 000 493

Further Information

4G/LTE Gateway
The 4G/LTE Gateway is a small, lightweight, and energy-efficient industrial
gateway equipped with mission-critical
LTE capabilities, Gigabit Ethernet interface, digital Inputs/Outputs, and microUSB port.
This 4G/LTE Gateway has been speciallyselected for use with the XL2 Sound Level Meter. It connects XL2+NetBox to theinternet for remote monitoring of noiselevels.
NTi Audio #:• 600 076 011
4G/LTE Gateway for NetBox(worldwide excluding Americas, China,
Japan)• 600 076 012
4G/LTE Router for NetBox(worldwide)

WP30 Weather Protection
Protect your measurement microphones
M2230 and M2340 from rain, wind, dust
and perching birds with this professional
outdoor weather protection kit. Ideal
for precise acquisition of environmental
noise data in outdoor applications.
Features• Class 1 compliant with IEC 61672 andANSI S1.4 for vertical and horizontal
sound incidence• Protection from rain and dust (IP54),
wind and perching birds• Built from corrosion-free materials• Removable top section for easy microphone calibration• Standard 3/8” tripod mount• Weight: 270 g (9.5 oz.)
• Optional Pole Mount Adapter• Optional sturdy outdoor carrying caseavailable
NTi Audio # 600 040 060

265Further Information

WP61 Weather Protection for M4261
Protect your M4261 microphone fromrain, wind, dust and perching birds withthis professional outdoor weather protection kit.
Features• Class 2 compliant with IEC 61672 andANSI S1.4 for vertical and horizontal
sound incidence• Protection from rain and dust (IP54),
wind and perching birds• Built from corrosion-free materials• Removable top section for easy microphone calibration• Standard 3/8” tripod mount• Weight: 270 g (9.5 oz.)
• Optional Pole Mount Adapter• Optional sturdy outdoor carrying caseavailable
NTi Audio # 600 040 080

266

Pole Mount Adapter
The outdoor measurement microphone
may be installed on a pole using thisadapter. The microphone is connected tothe sound level meter by the ASD cable,
which runs through the pole and theadapter to the microphone. The adapter
is available in two different sizes.
NTi Audio #:• 600 040 067
Pole Mount Adapter PM 1”
supports pole diameter 25 - 33 mm(1-1.3”)• 600 040 068
Pole Mount Adapter PM 1 1/4”
supports pole diameter 32 - 44 mm(1.25-1.75”)

Further Information

Limit Light
The XL2 Audio and Acoustic Analyzer in
combination with this Limit Light offersa turnkey solution for live sound monitoring. The sound level limits are set in the
XL2. The Limit Light provides a pre-warning with an orange light and indicates thatlevels have been exceeded with a red
light.
NTi Audio #: 600 000 600
Stack Light
The XL2 Audio and Acoustic Analyzer in
combination with this Stack Light provides a turnkey solution for noise levelmonitoring or passed / failed measurements where a prominent visual indication is required. The Stack Light connects
directly to the XL2 Analyzer and shows
the actual measurement result with threedifferent colors; green, orange and red.
NTi Audio #: 600 000 610

Class 1 Sound Calibrator
The battery-operated Class 1 Sound
Calibrator is classified for the calibrationof class 1 measurement microphones,
sound level meters and other acoustic
measurement equipment. This precision
microphone calibrator delivers 94 or 114
dB at a frequency of 1 kHz.
NTi Audio #: 600 000 388
The optional 1/4” adapter ADP-1/4-P isrequired to fit 1/4” measurement microphones.
NTi Audio #: 600 000 391
Class 2 Sound Calibrator
The battery-operated Class 2 Sound
Calibrator is classified for the calibrationof class 2 measurement microphones,
sound level meters and other acoustic
measurement equipment. This microphone calibrator delivers 114 dB at a frequency of 1 kHz.
NTi Audio #: 600 000 394

267

Further Information

Weatherproof Enclosure for
Noise Monitoring Terminal
The weatherproof enclosure is the tailored fixed installation solution for unattended noise monitoring. The enclosure is
IP66 rated, highly secure and constructedof strong, hard-wearing reinforced fiberglass.
NTi Audio #: 600 000 480
Shroud MXA01
The Shroud reduces the acoustic reflections from the XL2 housing back to themicrophone capsule for precision class
1 measurements. It supports the XL2 incombination with the 1/2” measurement
microphones M2230, M2340, M2211 andM2215. The Shroud is included within theType Approval Option.
NTi Audio #: 600 040 110

268

Basic Outdoor Case
The Basic Outdoor Case is a simple and efficient solution for outdoor noise monitoring. Powered either by an external mains
supply or a small, high-capacity battery
pack, the case is more than adequate fora number of days of monitoring. The robust and lightweight design protects the
XL2 and accessories from a wide range
of inclement weather conditions.
NTi Audio #:• IP43 rating: 600 000 471• IP63 rating: 600 000 473
Heavy-duty Outdoor Case
The heavy-duty outdoor case is a professional solution for short- and mediumterm unattended noise monitoring. The
case provides comprehensive protection
against dust, water and impacts. Internal
dimensions provide ample space for battery packs to power the XL2 Sound Level
Meter.
NTi Audio #:• IP43 rating: 600 000 476• IP65 rating: 600 000 477

Further Information

GPS Receiver (customized)
The specially adapted GNSS receivercomes with a built-in active antenna ina white housing. It connects to the XL2Sound Level Meter and the NetBox. Typical applications are to synchronize thestart time of one or multiple XL2s precisely with the GPS signal (+/- 0.7 ms) orpresenting the precise instrument position in NoiseScout Gateway mode for unattended noise and vibration monitoring.
The GNSS receiver supports Galileo, GPS
and other systems.
NTi Audio #: 600 000 357
Data Explorer Software
Data Explorer is a PC-based software application with a powerful data processor
for easy and fast analysis of sound levelmeasurement data. The data import requires that the Data Explorer Option be
installed on the XL2. Download the software at https://my.nti-audio.com.

Sound Insulation Reporter Software
Sound Insulation Reporter is a PC-based
software application that provides all thestandard reports for Airborne and Impact
sound insulation measurements. The
Sound Insulation Option enables the import of measurement data into the Sound
Insulation Reporter software. Download
the software at https://my.nti-audio.com.
Room Acoustics Reporter Software
The Room Acoustics Reporter is a PC software for automatically generating reverberation time measurement reports andanalyzing the RTA frequency response
spectrum. The Room Acoustics Option
enables the import of measurement data
into the Room Acoustics Reporter software. Download the software at https://my.nti-audio.com.

269

Further Information

Sound Power Reporter Software
Sound Power Reporter is a PC-based
software application that provides all thestandard reports for sound power measurements. The Sound Power Option
enables the import of measurement data
into the Sound Power Reporter software.
Download the software at https://my.ntiaudio.com.

89.4 dBA
85.3 dBLeq

XL2 Projector PRO Software
The Projector PRO software displays the
XL2 screen in real-time on your PC whenconnected by USB. The Projector PRO option enables the “XL View” and “Sound
Level Predictor” for live sound monitoring. Free download from the XL2 Support
Page at https://my.nti-audio.com.
1/2” Windscreen 90 mm
for M2230, M2340, M2211 and M2215
measurement microphone
NTi Audio #: 600 040 109

270

WP30/WP61 Windscreen Replacement
The replacement package contains twospare windscreens for outdoor measurement microphones. The outdoor windscreen is recommended to be replaced
annually.
NTi Audio #: 600 040 061
8 GB SD Card (default)
1x included with XL2
NTi Audio #: 600 000 374

Further Information

SD Card 32 GB
Every 32 GB SD Card is individually tested.
The XL2 requires an SD card that can continuously and simultaneously store many
data streams. Unfortunately, many cards
available on the market are known to interrupt the read/write process for periodsof more than 10 seconds. This leads todata loss in the XL2. These interruptions
can occur regardless of the speed ratingof the card. Even cards of the same typeand from the same vendor behave differently depending on the production date.
Therefore, to ensure the integrity of the
XL2 data recording, NTi Audio verifies every single card over a period of several
days before the card is sent to our customer. Requires XL2 Firmware V4.10 or
higher.
Requires XL2 Firmware V4.10 or higher.

Lightweight Tripod
Retractable, lightweight tripod with 1/4”
ball head and 3/8” mounting thread. The
flexible ball head mounts the XL2 Analyzer at any angle. The tripod is suitable
for all measurement microphones, outdoor measurement microphones and the
TalkBox.
NTi Audio #: 600 000 397
Minirator MR-PRO
The MR-PRO is an extremely powerfulanalog audio generator designed for the
professional engineer. It generates thefollowing analog audio signals:• Sine Waveforms, freely selectable frequencies and levels up to +18 dBu• Sweep Signals, any frequency interval
up to 1/12 octave• White Noise, Pink Noise• Polarity Test Signal• Delay Test Signal• Uploaded wav-files (*.wav)
NTi Audio #: 600 000 310

NTi Audio #: 600 000 386

271

Further Information

NTi Audio TalkBox
The NTi Audio TalkBox greatly simplifies
the acoustic feed of the STIPA intelligibility test source signal into closed soundreinforcement systems. It presents thestandardized voice-like acoustic signal
emission simulating a human talker in accordance with IEC 60268-16, combinedwith a certified speech intelligibility signal
at standardized levels.
NTi Audio #: 600 000 085
Tracer Battery Adapter Cable
The Tracer Battery Adapter Cable connects the Tracer battery pack to a NetBox
or an XL2 Analyzer. It ensures that theconnected instruments start up properly
if the battery has been completely discharged.
NTi Audio #: 600 000 478

272

Warranty Conditions
International warranty
NTi Audio guarantees the function of its products and the individual components for a period of one year from the dateof sale. During this period, defective products will either be
repaired free of charge or replaced.
Limitations
These guarantee provisions do not cover damage caused by accidents, transportation, incorrect use, carelessness, non-original accessories, the loss of parts, operation with non-specified
input voltages, adapter types or incorrectly inserted batteries.
NTi Audio accepts no responsibility for subsequent damage ofany kind. The warranty will be voided by carrying out repairs
or services by third parties who are not part of an approved
NTi Audio Service Centre.
Statutory Rights
Consumers may have legal (statutory) rights under applicablenational laws relating to the sale of consumer products. This
warranty does not affect your statutory rights. You may assert
any legal rights you have at your sole discretion.

Further Information

Service and Repairs

Calibration Certificate

If your product is not functioning correctly or is damaged,please contact the local NTi Audio partner for assistance. If
the product needs to be returned for service, kindly follow theservice guidelines at www.nti-audio.com/service.

Your NTi Audio instrument has been tested during manufacture
and conforms to the specifications listed in “Technical Data”.

Damage through shocks and moisture• The protective shock jacket shields the instrument against reasonable impacts that could
occur in normal use.
• Do not intentionally subject the instrument to
extreme stress!
• Please do not drop the instrument!
• Damage caused by dropping or impact is notcovered by warranty.
• Do not use the instrument in damp environments! The instrument can be permanently
damaged if exposed to moisture.

You may order a manufacturer calibration certificate of yournew instrument at the local NTi Audio partner either with or
any time after the purchase of the instrument. The certificate
lists the individual instrument data with serial number recorded
prior to the shipment.

The XL2 combination with the appropriate measurement microphone forms a precise class 1 or class 2 sound level meterin accordance with the standards and configurations listed in“Technical Data”.

NTi Audio recommends annual calibration of the products starting one year after the purchase. The calibration provides documented and traceable measurement accuracy and confirmsthat your NTi Audio product meets or exceeds the publishedspecifications. The calibration and adjustment procedures follow the documentation and traceability requirements of the
EN ISO / IEC 17025 standard.
For calibrations kindly follow the service guidelines atwww.nti-audio.com/service.
273

Further Information

Sample Calibration Certificate
Calibration of:
Serial Number:
Date:

XL2 Audio and Acoustic Analyzer
A2A-11667-E0
25 July 2016

• Measurement Data on Receipt:

in tolerance• Detailed Calibration Test Results:

RMS Level @ 1kHz, XLR Input

Manufacturer Calibration Certificate

Flatness, XLR Input1

20 Hz
20 kHzFrequency• Device Type:XL2 Audio and Acoustic Analyzer

THD+N @ 0 dBu, 1 kHz, XLR Input• Serial Number:

A2A-11667-E0

before
0.100
0.999
9.987

actual
0.100
1.000
9.989

unit
V
V
V

actualerror

XL2
tolerance

calibration
uncertainty2

≤0.1%
≤0.1%
-0.1%

±0.5%
±0.5%
±0.5%

±0.10%±0.09%±0.09%

1
1

0.997
1.004

0.996
1.004

V
V

-0.4%
0.4%

±1.1%
±1.1%

±0.09%±0.09%

1000.00 999.99

Hz≤0.003%±0.003%±0.01%<2 uV±0.50%

typ. -100 dB±0.50%

1000

Sa

The following instrument has been tested and calibrated to the manufacturer specifications.
The calibration is traceable in accordance with ISO/IEC 17025 covering all instrument functions.

reference
0.1
1
10

Residual Noise

Temperature:
Relative Humidity:< 2 uV

-98.5

-98.9

28.2
51.7

dB

°C
%

pl

e

pl

m

• Calibration Equipment Used:< 2 uVm

Sa• Test Conditions:

XLR- Agilent Multimeter, Typ 34401A, Serial No. MY 5300 4607
Last calibration: 17.08.2016, Next calibration: 17.08.2017
Calibrated by ELCAL to the national standards maintainedat Swiss Federal Office of Metrology. SCS 002

25 July 2016

• Certificate Number:

42576-A2A-11667-E0• Results:

PASSED(for detailed report see next page)- FX100 Audio Analyzer, Serial No. 10408
Last Calibration: 04.05.2016, Next Calibration: 04.05.2017
Manufacturer calibration based on Agilent 34410, Serial No. MY47014254,
Last Calibration: 03.06.2016, Next Calibration: 03.06.2017
which is calibrated by ELCAL to national standards maintainedat Swiss Federal Office of Metrology. SCS 002

Tested by:

M. Frick1e• Date of Calibration:

Signature:

The specified tolerance +/-0.1 dB @ 1V = +/- 1.1%

2 The reported expanded uncertainty is based on a standard uncertainty multiplied by a coverage factor k=2, providing alevel of confidence of approximately 95%. The uncertainty evaluation has been carried out in accordance with theregulations of the GUM.

Stamp:NTi Audio AG • Im alten Riet 102 • 9494 Schaan • Liechtenstein • Europe • Tel: +423 239 6060
www.nti-audio.com • HR-Nr: 2.012.557 • MwStNr: 54306 • Bank: VP Bank, Vaduz, Acc No: 322.235.015

NTi Audio AG • Im alten Riet 102 • 9494 Schaan • Liechtenstein • Europe • Tel: +423 239 6060
www.nti-audio.com • HR-Nr: 2.012.557 • MwStNr: 54306 • Bank: VP Bank, Vaduz, Acc No: 322.235.015

274

1/2

2/2

Further Information

Declaration of Conformity

Position: COO

CE / FCC Compliance Statement

Information for Disposal and Recycling

We, the manufacturer NTi Audio AG, Im alten Riet 102, 9494
Schaan, Liechtenstein, do hereby declare that the XL2 Analyzer, the measurement microphones M2230, M2340, M2211,
M2215, M4261, the preamplifiers MA220, MA230 and accessories, comply with the following standards or other standard
documents:• EMC: 2014/30/EU• Harmonized standards: EN 61326-1• Explosive atmospheres (ATEX): 2014/34/EU• Directive 2011/65/EC on the restriction of the use of certain
hazardous substances in electrical and electronic equipment(RoHS).
• Directive 2012/19/EU on waste electrical and electronicequipment (WEEE).
This declaration will become invalid if modifications to the
instrument are carried out without the written approval of
NTi Audio.

Dispose of the instrument in accordance withthe legal environmental regulations in the
country.

Regulations for the EU and other European countries
with corresponding laws
The instrument must not be disposed of in the household garbage. At the end of its service life, bring the instrument to acollecting point for electrical recycling in accordance with thelocal legal regulations.

Other countries outside the EU
Contact the respective authorities for the valid environmental
regulations in the country.

Date: 25. July 2019		

275

Specifications

23. Technical Data XL2All specifications are according to the IEC61672 standard. Other standards are listed the corresponding specifications.

Product Configurations
Class 2

• XL2 with M4261 microphone
Class 2 in accordance with IEC 61672 andANSI S1.4

Conforms
with Standards• IEC 61672:2013, IEC 61672:2003,
IEC 61260:2014, IEC 61260:2003,
IEC 60651, IEC 60804, IEC 61183• SMPTE ST 202:2010, ISO 2969:2015• China: GB/T 3785:2010, GB/T 3241, GB 3096-2008,
GB 50526, GB-T 4959
• Germany:» DIN 15905-5, DIN 45657:2014, DIN 45657:2005,
DIN 45645-2» DIN 45645-1(optional with Extended Acoustic Pack)• Japan: JIS C1509-1:2005, JIS C 1513 class 1,
JIS C 1514 class 0• Switzerland: V-NISSG• UK: BS 4142:2014, BS 5969, BS 6698
• US: ANSI S1.4:2014, ANSI S1.43, ANSI S1.11:2014,
ANSI/ASA S12.60• International IEC standards are adopted as European
standards and the letters IEC are replaced by EN.
XL2 conforms to these EN standards.
• WELL Buildings, LEED Green Building• FGI Facility Guidelines Institute

Weighting• Frequency weighting: A, C, Z (simultaneous)• Time weighting: (simultaneous)» Fast, Slow
» Impulse (optional with Extended Acoustic Pack)

Level Details• Measurement bandwidth (-3dB): 4.4 Hz - 23.0 kHz• Level resolution: 0.1 dB• Internal noise: 1.3 µV A-Weighted

Sound Level Meter
Certified
Product Configurations
Class 1

• XL2 with TA-Option, M2230 Microphone andShroud MXA01 form an integrating sound level
meter with type approval in accordance withclass 1 requirements of IEC 61672 and ANSI S1.4

Product Configurations
Class 1The XL2 is identical to the certified configuration,
just using the latest firmware.
• XL2 with M2230 or M2340 microphone
Class 1 in accordance with IEC 61672 andANSI S1.4• XL2 with M2211 or M2215 microphone
Class 1 frequency response in accordance withIEC 61672 and ANSI S1.4
These specifications apply for operation with themicrophone attached using the Shroud MXA01 or
the microphone detached using the ASD cable. This
prevents possible acoustic reflections from the XL2
housing and ensures a high measurement accuracy
in accordance with the standards IEC 61672 andANSI S1.4.

276

Specifications

Audio
Recording• Default» Recording of compressed wav-files(ADPCM - 4 bit, 24 kHz)
» a new wav-file starts every 12 hours(max. wav-file size 512 MB)» Bandwidth: 2.0 Hz - 10.2 kHz• Optional: Extended Acoustic Pack
» Recording of linear wav-files (24 bit, 48 kHz)
» a new wav-file starts every 1 hours(max. wav-file size 512 MB)» Bandwidth: 2.0 Hz - 23.6 kHz• Optional: NoiseScout - Managed Mode
» Recording of compressed wav-files(4 bit, 12 kHz)» Bandwidth: 2.0 Hz - 5.1 kHz» requires activated “NoiseScout 365” or“Data Day Credits”• Audio files include meta data (scaling, time, ...) in
Broadcast Wave Format BWF according to EBUTECH 3285

Measurement
Ranges withdifferent
microphones• XL2+M2230: 17 dB(A) - 137 dB• XL2+M2340: 18 dB(A) - 138 dB• XL2+M2215: 25 dB(A) - 153 dB• XL2+M2211: 21 dB(A) - 144 dB• XL2+M4261: 27 dB(A) - 146 dB@ typical microphone sensitivity

Linear Measurement
Range acc.
IEC61672 /ANSI S1.4• XL2+M2230: 24 dB(A) - 137 dB, 27 dB(C) - 137 dB• XL2+M2340: 25 dB(A) - 138 dB, 28 dB(C) - 138 dB• XL2+M2215: 33 dB(A) - 153 dB• XL2+M2211: 29 dB(A) - 144 dB• XL2+M4261: 33 dB(A) - 146 dB@ typical microphone sensitivity

StabilizationTime< 10 seconds

Integration
Time• Minimum: 1 second• Maximum: 100 hours minus 1 second

Display
Measurement
RangesThree level ranges depending on the microphonesensitivity with manual setting. For example:• M2230, M2340 @ sensitivity = 42 mV/Pa» LOW, lower level range: 0 - 100 dBSPL» MID, mid-level range: 20 - 120 dBSPL» HIGH, upper level range: 40 - 140 dBSPL• M2215 @ sensitivity = 8 mV/Pa» LOW, lower level range: 20 - 120 dBSPL» MID, mid-level range: 40 - 140 dBSPL» HIGH, upper level range: 60 - 160 dBSPL• M2211 @ sensitivity = 20 mV/Pa» LOW, lower level range: 10 - 110 dBSPL» MID, mid-level range: 30 - 130 dBSPL» HIGH, upper level range: 50 - 150 dBSPL• M4261 @ sensitivity = 16 mV/Pa» LOW, lower level range: 10 - 110 dBSPL» MID, mid-level range: 30 - 130 dBSPL» HIGH, upper level range: 50 - 150 dBSPL

277

Specifications

Residual
noise in [dB]@S=
42 mV/Paof XL2
without
measurement
microphone• Frequency weighting A
Level range

Leq

Lpeak

LOW

4

17

MID

18

31

HIGH

43

55

• SPL actual, Lmin, Lmax, Lpeak, Leq, Lp• Gliding LAeq and LCeq with selectable time window from one second to one hour(=running Lxeq or sliding Lxeq with x= A or C)• All measurement results simultaneously available• Correction value measurement wizard based on
LAeq, LCeq and LCpeak• Noise exposure level LEX with post-processing• Logging all data or subsets in selectable intervals• Recording of voice notes• Monitoring of sound levels that exceed limits• Digital I/O interface for external peripherals control

Real-Time
Analyzer
RTA• Conforms with class 1 of IEC 61260:2014 and
ANSI S1.11-2014• 1/1 octave band display: 8 Hz - 16 kHz
sub ranges 8 Hz - 4 kHz or 31.5 Hz - 16 kHz• 1/3 octave band display: 6.3 Hz - 20 kHz
sub ranges 6.3 Hz - 8 kHz or 20 Hz - 20 kHz• Level resolution: 0.1 dB• Measurement Units: Volt, dBu, dBV and dBSPL• Band pass filters (base 10) conform with class 1 of
IEC 61260:2014 and ANSI S1.11-2014» 1/1 octave spectrum: > 16 Hz band» 1/3 octave spectrum: > 16 Hz band
• Broadband A/Z levels simultaneously• Frequency weighting: X-Curve @ 500 seats in accordance with SMPTE ST 202:2010 and
ISO 2969:2015 (not available for XL2-TA)• Capturing of a single reading into the internal
memory for comparative measurements• Leq logging• Frequency weighting C
Level range

Leq

Lpeak

LOW

3

16

MID

17

30

HIGH

41

55

• Frequency weighting Z

278

Measurements

Level range

Leq

Lpeak

LOW

7

20

MID

21

34

HIGH

46

58

Specifications

RemoteMeasurement(optional)• Querying measurement data online via the USB
interface of the following functions:» Sound level meter and spectrum analyzer
SLMeter/RTA» FFT analyzer» RT60 reverberation time
» Audio analyzer RMS/THD+N» High-resolution spectral analyzer 1/12 Oct + Tol• Typical response time: 10 ms@ querying the frequency spectrum in SLMeter

Functions ofExtended
Acoustic
Pack(optional)• SLMeter/RTA function» Recording of linear wav-files (24 bit, 48 kHz)a new wav-file starts every 1 hour (max. wav-filesize 512 MB)» Percentiles for wide band, 1/1 and 1/3 octave
spectrum- Flexible setting from 0.1% to 99.9%- Sampling: every 1.3 ms- Wide band: in 0.1 dB wide classes, based on
sampling Lxy (x= A, C or Z, y= F, S or EQ1”)- 1/1 and 1/3 octave spectrum: in 1.0 dB wideclasses, based on Lxy (x= A, C or Z, y= F or S)- Dynamic range: 140 dB» Sound Exposure Level LAE» 100ms logging» RTA logging of Lmin and Lmax
» Event-triggered audio and data recording» Time weighting: Impulse(LxI, LxIeq with x= A, C, Z)» True peak level in 1/1 and 1/3 octave resolution» Clock-Impulse Maximum Level (TaktMax) in accordance with DIN 45645-1 and DIN 45657» Impulsiveness detection in accordance with
BS4142:2014 and NordTest ACOU 112• FFT function» High-resolution Zoom-FFT with selectable frequency ranges and resolution up to 0.4 Hz in therange of 5 Hz to 20 kHz» Recording of linear wav-files (24 bit, 48 kHz)• RT60 function» Reverberation time in 1/3 octave resolution• 1/12 octave Spectral Analyzer(requires Spectral Limits Option)» Recording of linear wav-files (24 bit, 48 kHz)279

Specifications

Functions ofSpectral
Limits
Option(optional)

280• SLMeter/RTA function» True peak level in 1/1 and 1/3 octave resolution• FFT function» High-resolution Zoom-FFT with selectable frequency ranges and resolution up to 0.4 Hz» Sound mode: 5 Hz to 20 kHz» Vibration mode: 1 Hz to 20 kHz• 1/12 octave function» High-resolution RTA function “1/12 Oct + Tol”
» Selectable 1/1, 1/3, 1/6 and 1/12 octave spectral
resolution» Frequency band listening at rear speaker» Sound Mode: 11.5 Hz to 21.8 kHz» Vibration mode: 0.73 Hz to 1.36 kHz• FFT and 1/12 octave function» Capturing of multiple readings into the internal
memory» Comparing measurement results against captures with relative or absolute curve display» Comprehensive tolerance handling with tolerance masks based on captures for passed/failed
measurements» Export and import of tolerance and capture files• Noise Curves» Noise Rating NR according to ISO/R 1996-1971» Noise Criteria NC
in accordance with ANSI S12.2-2019 and -1995» Room Noise Criteria RNC
in accordance with ANSI S12.2-2019» Room Criteria RC
in accordance with ANSI S12.2-1995» Preferred Noise Criteriain accordance with ASA 1971

Reporting and Analysis Software
Data
Explorer(optional)• Enables the import of measurement data into the
Data Explorer software• Powerful data processor for easy and fast analysis
of sound level measurement data on PC

Sound
Insulation
Reporter(optional)• Enables the import of RTA and reverberation timemeasurement data in 1/3 octave band resolution
into the XL2 Sound Insulation Reporter software• Software provides all tools for fast data analysis
and standardized reporting of airborne, impact andfacade sound insulation measurements on PC• Standards ASTM E336, ASTM E413, ASTM E1007,
ASTM E989, ASTM E966, ASTM E1332, BB93,
DIN 4109, Document E, GB/T 19889, ISO 16283,
ISO 140, ISO 717, ISO 10140, NEN 5077:2019, SIA
181:2006, SIA 181:2020

Room
Acoustics
Reporter(optional)• Frequency response spectrum and Noise Curves• Room acoustic simulation according to Sabine or
Eyring• Import of own sound absorber database and tolerances• Standards GB 50371, IEC 61260, ANSI/ASA S12.22019, DIN 15996:2020, ISO R 1996-1971, ASR
A3.7:2021, DIN 18041:2016, ISO 3382-1:2009,
ISO 3382-2:2008, ÖNORM B 8115-3:2015, ASTM
C423-17, ISO 354:2003

Specifications

Sound
Power
Reporter(optional)• Enables the import of RTA and reverberation timemeasurement data in 1/1 and 1/3 octave band resolution into the Sound Power Reporter software• Software provides all the standard reports forsound power measurements• Standards ISO 3741, ISO 3744, ISO 3746, ANSIASA S12.51, S12.54, S12.56

Acoustic Analyzer
FFT Analysis• Real-time FFT with actual level, Leq, Lmin, Lmax
• Level resolution: 0.1 dB• Frequency Band Ranges: 7 Hz - 215 Hz,
58 Hz - 1.72 kHz, 484 Hz - 20.5 kHz with 143 frequency bins shown on display• Measurement Units: Volt, dBu, dBV and dBSPL• Optional with Extended Acoustic Pack or Spectral
Limits: High-resolution Zoom-FFT with selectablefrequency ranges and resolution up to 0.4 Hz in
the range of 5 Hz to 20 kHz• Optional with Spectral Limits:
Capture and tolerance function with multiple readings for comparative measurements and passed/
failed analysis

Reverberation
Time RT60• Conforms with ISO 3382 and ASTM E2235• 1/1 octave bands results from 63 Hz - 8 kHz,based on T20 and T30• Optional with Extended Acoustic Pack:
1/3 octave bands results from 50 Hz - 10 kHz
based on T20 and T30• Range: 10 ms - 30 seconds• Minimum reverberation time (typical)» < 100 Hz: 0.3 second» 100 - 200 Hz: 0.2 second» > 200 Hz: 0.1 second• Measurement based Schroeder-method• Test signal: Impulse source or interrupted pinknoise generated by the MR-PRO, MR2 or the included NTi Audio Test CD / USB Flash Drive281

Specifications

Polarity• Checks polarity of speakers and line signals• Positive/Negative detection of wideband andindividual 1/1 octave bands through internal microphone or XLR/RCA connector• Test signal: NTi Audio polarity test signal generated by the MR-PRO, MR2 or the included NTi
Audio Test CD / USB Flash Drive

Delay Time

• Propagation delay between electrical reference
signal and acoustic signal using the internal microphone• Range: 0 ms - 1 second (0 m - 344 m)• Resolution: 0.1 ms• Test signal: NTi Audio delay test signal generated
by the MR-PRO, MR2 or the included NTi Audio
Test CD / USB Flash Drive

Noise
Curves• Noise Rating NR according to ISO/R 1996-1971• Noise Criteria NC
in accordance with ANSI S12.2-2019 and -1995• Room Noise Criteria RNC
in accordance with ANSI S12.2-2019• Room Criteria RC
in accordance with ANSI S12.2-1995• Preferred Noise Criteriain accordance with ASA 1971
• Application range of measurement microphones:» M2230: down to NC15
» M2340: down to NC15
» M2211: down to NC20
» M4261: down to NC25

282

1/12 Octave
Analysis(optional)• Actual level, Lmin, Lmax, Leq, Leq1”, Leq4”• Selectable 1/1, 1/3, 1/6 and 1/12 octave spectral
resolution• Measurement Units: Volt, dBu, dBV and dBSPL• Band pass filters (base 10)• Capturing of multiple readings into the internal
memory• Comparing measurement results against captureswith relative or absolute curve display• Comprehensive tolerance handling• Creating tolerance masks based on captures forpassed/failed measurements

CinemaMeter(optional)• Measurements in 1/3 octave resolution in accordance with SMPTE ST 202:2010 and SMPTE RP
200:2012• An interactive assistant guides the user throughdedicated measurement procedures.
• Consists of» Spectral Limits Option
NTi Audio # 600 000 376» Cinema Assistant Option
NTi Audio # 600 000 378

Specifications

STIPA
SpeechIntelligibility(optional)• Measurement in accordance with the standards» IEC 60268-16 (edition 2, 3, 4 or 5)» AS 1670.4» BS 5839-8» CEN/TS 54-32:2015» DIN EN 50849:2017» ISO 7240-16» ISO 7240-19:2007» DIN VDE 0833-4» VDE V 0833-4-32:2016» VDE 0828-1:2017-11» NFPA 72» UFC 4-021-01• Direct measurement method (IEC 60268-16)• Frequency range: 125 Hz - 8 kHz in octave band
• Modulation frequencies 0.63 Hz - 12.5 Hz in thirdoctave resolution• Single value STI and CIS test result• Ambient noise correction• Automated averaging of measurements• Modulation indices and individual band level results with error indicator• Test signal: NTi Audio STIPA signal generated by
the MR-PRO, NTi Audio TalkBox or other audio
players (download wav-file at https://my.nti-audio.
com/support/xl2)

Audio Analyzer
Conforms
with Standards• IEC 61672, IEC 60651, IEC 60804• DIN EN 60065, VDE 0860, IEC 468-4

Level RMS

• True RMS detection in V, dBu, dBV, dBSPL(dBSPL not available for XL2-TA)• Power measurement in Watt W or dBm
with flexible load setting from 1.0 to 9999 Ohm• Range XLR/RCA input: 2 µV - 25 V (-112 dBu to+30 dBu)• Accuracy: ± 0.5 % @ 1 kHz,• Flatness: ± 0.1 dB @ 12 Hz to 21.3 kHz• Bandwidth (-3 dB): 5 Hz to 23.6 kHz• Resolution: 3 digits (dB scale),5 digits (linear scale)or 6 digits (x1 scale)

Real-Time
Analyzer
RTA

Following measurement functions offer audio spectrum in Volt, dBu and dBV• Sound Level Meter• FFT• 1/12 Octave (optional with Spectral Limits)

Frequency• Range: 9 Hz to 21.3 kHz• Resolution: 6 digits• Accuracy: < ± 0.003%

THD+N(Total Harmonic
Distortion +Noise)• Range: -100 dB to 0 dB (0.001% to 100%)• Minimum level: > -90 dBu• Fundamental frequency range: 10 Hz to 21.3 kHz• Measurement bandwidth: 2 Hz to 23.6 kHz• Resolution: 3 digits (dB scale) or 4 digits (linear
scale)• Residual THD+N @ XLR/RCA input: < 2 µV

283

Specifications

Scope

Auto ranging, auto scaling

Filter• Frequency weighting: A, C, Z
• Highpass 100Hz, 400 Hz, 19 kHz,• Bandpass 22.4 Hz - 22.4 kHz in accordance with
IEC468-4

RemoteMeasurement(optional)

Querying measurement data online via the USB
interface of the following functions:• Sound level meter and spectrum analyzer
SLMeter/RTA• FFT analyzer• RT60 reverberation time
• Audio analyzer RMS/THD+N• High-resolution spectral analyzer 1/12 Oct + Tol

Calibration
Free-field
Correction• NTi Audio Class 1 Sound Calibrator» M2230: -0.1 dB» M2340: -0.1 dB» M2211: -0.1 dB» M2215: -0.1 dB• NTi Audio Class 1 Sound Calibrator with
1/4” Calibration Adapter, type ADP 1/4-P» M4260: +0.1 dB» M4261: +0.2 dB

Wind Screen
Correction• 50 mm Wind Screen: +0,12 dB• 90 mm Wind Screen: +0,19 dB• WP30/WP61 Wind Screen 90 mm: +0,19 dB

284

Calibration• Recommended calibration interval: one year
• Microphone calibration with external calibrator
supported• Optional calibration certificate for new instruments available

Vibration Meter
Channels• 1 (Single-channel)

Parameters• Real time measurement in» Acceleration: m/s2, g, in/s2, dB» Velocity: m/s, in/s, dB» Displacement: m, in, dB» Peak particle velocity PPV: mm/s, in/s
» Levels: RMS, Peak, Peak-Peak

VibMeter• Broadband level» Frequency range: 0.8 Hz - 2.5 kHz• Spectral» 1/1 octave band display: 1 Hz - 2.0 kHz
sub ranges 1 Hz - 500 Hz or 4 Hz - 2 kHz» 1/3 octave band display: 0.8 Hz - 2.5 kHz
sub ranges 0.8 Hz - 1.0 kHz, 2.5 Hz - 2.5 kHz» Broadband level measured withbandwidth (- 3dB): 0.7 Hz – 23.6 kHz• Display according to DIN 45669-1:2010» Unweighted velocity v(t)» Maximum absolute velocity ¦v¦max» Averaging duration Tm» Measurement duration TM

Specifications

Filter• Flat (no filter)
Bandwidth (- 3dB): 0.7 Hz – 23.6 kHz• 10 - 1000 Hz according to ISO 2954 with decayrate = 18 dB / octave• 1 - 80 Hz, 1 - 315 Hz acc. to DIN 45669-1:2010
with decay rate = 12 dB / octave

Audio
Recording in
VibMeter• Default» Recording of compressed wav-files(ADPCM - 4 bit, 24 kHz)
» a new wav-file starts every 12 hours(max. wav-file size 512 MB)» Bandwidth: 2.0 Hz - 10.2 kHz• Optional: Extended Acoustic Pack
» Recording of linear wav-files (24 bit, 48 kHz)
» a new wav-file starts every 1 hours(max. wav-file size 512 MB)» Bandwidth: 2.0 Hz - 23.6 kHz

FFT Analysis• Frequency range: 1 Hz - 1.69 kHz• Optional with Extended Acoustic Pack or Spectral Limits: High-resolution Zoom-FFT with selectable frequency ranges and resolution up to
0.4 Hz in the range of 1 Hz to 20 kHz

1/12 Octave
Analysis(optional)• Actual level, Lmin, Lmax, Leq, Leq1”, Leq4”• Selectable 1/1, 1/3, 1/6 and 1/12 octave spectral resolution• Measurement Units» Acceleration: m/s2, g, in/s2, dB» Velocity: m/s, in/s, dB» Displacement: m, in, dB• Band pass filters (base 10)• Frequency range: 0.73 Hz - 1.36 kHz

Maximum Input
Level• 353 m/s2, 36 g @ 20 mV/(m/s2)
with ICP Adapter ASD

Residual Noise(typical) withICP Adapter
ASD• 17 µV @ 0.7 Hz ... 23.0 kHz• 14 µV @ 1 Hz ... 315 Hz• 14 µV @ 1 Hz ... 80 Hz

Referencemeasurement
range

• Mid

285

Specifications

Input / Output Interfaces
Audio Inputs

Audio
Outputs• Built-in speaker• Headphone connector» 3.5 mm Minijack» mono monitor wired to both channels of stereo
jack» Linear output signal over a measurement rangeof 57 dB in SLMeter measurement function» Maximum output level: 0.33 Vrms / 0.47 Vp

USB Interface

USB mini connector for data transfer to PC, XL2
Projector PRO and/or charging of Li-Po battery

Digital I/O

Connection interface to accessories• XL2 Input Keypad• Limit Light• Stack Light• Digital I/O Adapter PCB

TOSLink

24 bit linear PCM audio signal output(prepared for later firmware extension)

286

Memory• XLR balanced» Input impedance = 200 kOhm
» Phantom power: +48 VDC switchable with maximum 10 mA supply current in accordance withIEC 61938» Automated sensor detection for NTi Audio’s ASD
measurement microphones and pre-amplifiers• RCA unbalanced with input impedance >30 kOhm
• Built-in condenser microphone for polarity testing,delay measurements and voice note recording

SD Card included (8 GByte), removable, storingmeasurement data in ASCII format, screen shots,
voice notes and wav-files
Data logging every second offers following noisemonitoring periods:• Logging default noise levels: > 2 years• Additional logging of 1/3 octave data: > 6 month• Additional» compressed audio recording: > 1 week
» linear audio recording: > 15 hours
Optional 32 GB SD Cards are available for longer
monitoring requirements; requires XL2 Firmware
V4.10 or higher.

Power
Supply• Rechargeable Li-Po battery included» Type 3.7 V / 2260 mAh» Typical battery lifetime > 4 hours» Range: 3.3 - 4.5 VDC» Volume energy density = 339 Wh/l
• Dry cell batteries type AA, 4 x 1.5 V» Typical battery lifetime > 4 hours» Range: 3.7 - 6.0 VDC• Linear external power supply 9 VDC» Range: 7.5 - 20.0 VDC @ minimum 6 Watt
» Charges Li-Po battery during operation» Connector C5.5 x 2.1 x 12 mm• USB-Power Supply» for short-term operation < 1 day» charging power is equal or less than power consumption

Specifications

Power
Supply• External battery pack» 22 Ah battery pack: 4 days
» 44 Ah battery pack: 8 days

GeneralClock• Default» Real-time clock with lithium backup battery» Typical life backup battery: 8 years» Return instrument for battery replacement» Drift < 1.7 seconds per 24 hours• Special XL2 edition, NTi Audio # 600 000 356» VCXTO clock» Drift < 0.04 seconds per 24 hours

Mechanics• Tripod or microphone stand mount 1/4”
• Wire stand mounted on rear side
• Display: 160 x 160 pixels grey scale with LED backlight
• Dimensions (L x W x H)
» 180 mm x 90 mm x 45 mm» 7.1” x 3.5” x 1.8”
• Weight: 480 g (1 lb) including built-in Li-Po battery

Temperature-10 °C to +50 °C (14° to 122°F)

Humidity

5% to 90% RH, non-condensing

Static airpressure

65 kPa to 108 kPa

Susceptibility to radio
frequencies

Classification Group X

Electromagnetic Compatibility

CE compliant:
EN 61326-1 Class B, EN 55011 class B
EN 61000-4-2 to -6 & -11

Protection
Rating

IP51

ATEX• For applications in explosive atmospheres withinzone 2 in accordance with IEC 60079• Directive 2014/34/EU

287

Specifications

24. Technical Data Microphones

Classification with XL2 according to IEC 61672, ANSI S1.4
Consisting of

M2230

M2340
(with self-test)

Class 1
certifiedClass 1
certified

PreAmplfier
MA220 + MC230
or MC230A
CapsulePreAmplfier
MA230 +
MC230A
CapsuleMicrophone Type

System Self-test (CIC)

Frequency Response
Class 1
PreAmplfier
MA220 +
Capsule 7052

M4261
Class 2

PreAmplfier
MA220 +
Capsule 7056

1/2” detachable with 60UNS2 thread,type WS2F according IEC 61094-4
MA220

MA230

-

with XL2

Flatness tolerance bands
typicalActual Frequency Response

M2215(high levels)

M4261 microphone withpermanently installed
capsuleOmnidirectional, pre-polarized condenser,
free field microphone

Capsule / Transducer
PreAmplifier Type

M2211

1/4” permanently installed

MA220

-

±1 dB @ 5 Hz - 20 Hz±1 dB @ >20 Hz - 4 kHz±1.5 dB @ >4 kHz - 10 kHz±2 dB @ >10 kHz - 16 kHz±3 dB @ >16 kHz - 20 kHz+1/-4.5 dB @ 5 Hz - 20 Hz±1.5 dB @ >20 Hz - 4 kHz±3 dB @ >4 kHz - 10 kHz±4.5 dB @ >10 kHz - 16 kHz±5 dB @ >16 kHz - 20 kHz

freely available as Excel-data, register product at https://my.nti-audio.com and contact info@nti-audio.com

Frequency Range

5 Hz - 20 kHz

Residual Noise Floor typical

16 dB(A)17dB(A)

21 dB(A)25 dB(A)27 dB(A)Maximum SPL@ THD 3%, 1 kHz, S_typical

137 dBSPL

138 dBSPL

144 dBSPL

153 dBSPL

142 dBSPL

288

Specifications

M2230

M2340
(with self-test)

Sensitivity typical @ 1 kHz-27.5 dBV/Pa±2 dB(42 mV/Pa)

Temperature Coefficient< -0.01 dB / °C

Temperature Range
Pressure Coefficient

M2215(high levels)

M4261-34 dBV/Pa±3 dB(20 mV/Pa)-42 dBV/Pa±3 dB(8 mV/Pa)-36 dBV/Pa±4 dB(16 mV/Pa)< ±0.015 dB / °C

< ±0.02 dB / °C

-10°C to +50°C(14°F to 122°F)

0°C to +40°C(32°F to 104°F)-0.005 dB / kPa-0.02 dB / kPa

Influence of Humidity(non-condensing)-0.04 dB / kPa< ±0.05 dB

Humidity< ±0.4 dB

5% to 90% RH, non-condensing

Long-term Stability> 250 years / dB

Power Supply
Current Consumption typical

M2211

-

48 VDC phantom power
2.3 mA

0.8 mA

2.3 mA

1.7 mAElectronic Data Sheet

NTi Audio ASD in accordance with IEEE P1451.4 V1.0, Class 2, Template 27

Output Impedance

100 Ohm balanced

Connector

Balanced 3-pole XLR

Diameter Dimensions
Length Dimensions

20.5 mm (0.8”)
154 mm (6.1”)

Weight

150 mm (5.9”)
100 g (3.53 oz)

Environmental Protection
Windscreen Diameter

IP51
50 mm (2”)

Scope of Supply
NTi Audio #83 g (2.93 oz)

90 mm (3.5”)

33 mm (1.3”)

33 mm (1.3”)

33 mm (1.3”)

Windscreen, Microphone Holder with Adapter 5/8“ - 3/8“, Manual
600 040 050

600 040 230

600 040 022

600 040 045

600 040 070
289

Specifications

Outdoor Measurement Microphones

Classification with XL2 according to IEC 61672, ANSI S1.4
System Self-test (CIC)

M2230-WP(M2230+WP30)

M2340-WP(M2340+WP30)

M4261-WP(M4261+WP61)

Class 1
certifiedClass 1
certifiedClass 2

with XL2--

Windscreen Diameter

90 mm (3.5”)

Diameter Dimensions

36 mm (1.4”)

36 mm (1.4”)

36 mm (1.4”)

Length Dimensions

378 mm (14.9”)378 mm (14.9”)378 mm (14.9”)

Weight430 g, 15.17 oz

430 g, 15.17 oz

413 g, 14.57 oz

IP54 in vertical position

IP54 in vertical position

Environmental Protection

IP54 in vertical position

Mounting
Optional Pole Mount Adapter
NTi Audio #290

Standard 3/8” tripod mount included• Pole Mount Adapter PM 1”
for pole diameter 25 - 33 mm (1-1.3”)• Pole Mount Adapter PM 1 1/4” for pole diameter 32 - 44 mm (1.25-1.75”)
600 040 050 + 600 040 060

600 040 230 + 600 040 060

NTi Audio # 600 040 067
NTi Audio # 600 040 068
600 040 070 + 600 040 080

Specifications

Typical Frequency Response of Measurement Microphones
M4261

M2230, M2340,
M2211, M2215

8
Tolerance
Class 1, IEC61672-1

6

Sensitivity relative [dB]

4

2

0

-2

-4

Tolerance
Class 2, IEC61672-1

-6

-8
5

10
10

20		

100				100

log frequency [Hz]

1000
1000

		

10000
10000

20000

(free field conditions @ reference direction 0°)291

Specifications

Linear Measurement Range
acc. IEC61672 / ANSI S1.4
(typ. microphone sensitivity)

292

XL2 + M2230: 24 dB(A) - 137 dB

XL2 + M2340: 25 dB(A) - 138 dB

XL2 + M2211: 29 dB(A) - 144 dB

XL2 + M4261: 33 dB(A) - 146 dB

Specifications

Free Field - Pressure Correction Factors
If a measurement microphone is held in a free-field environment, then the measurement microphone acts at high frequencies like a reflector. The sound pressure increases infront of the microphone capsule membrane. M2230, M2340,
M2211 and M2215 are free-field equalized measurement microphones, they compensate for the increased pressure internally. The calibration of the measurement microphones M2230
and M2340 with the B&K 4226 requires the accessory Adapter
Ring MXR01, NTi Audio # 600 040 105. Please note, nevertouch the diaphragm of the measurement microphone capsule.
The calibrator no longer offers free-field conditions. Therefore,
the free-field equalization of the microphone must be compensated. This needs to be considered prior the calibration. The
correction value needs​​
to be added to the pressure responseof the microphone.
Example:• During the calibration, the XL2 measures the sound level inthe calibrator. If the B&K 4226 calibrator is used and it is set
to 16 kHz, then the XL2+M2230 reads just 86.7 dBA.
• The free-field sound level is calculated by summing the XL2
measurement value and the correction value (86.7 dB +7.3 dB = 94.0 dB).

The following corrections apply with the B&K 4226 calibrator.

NominalFrequency[Hz]

M2230,
M2340
with
MXR01
Adapter
[dB]

M2211
[dB]

M2215
[dB]

Measurement
Uncertainty U
[dB]

31.5
63
125

-0.3
0.0
-0.2

-0.2
0.0
-0.1

0.0
0.0
-0.1

0.3
0.3
0.3

250
500
1000

-0.2
-0.2
0.0

-0.1
-0.1
0.0

-0.1
-0.1
0.0

0.3
0.3
0.3

2000
4000
8000

0.1
0.7
2.7

0.1
0.7
4.5

0.0
0.4
4.7

0.3
0.3
0.4

12500
16000

7.2
7.3

5.8
7.9

6.1
7.9

0.7
0.8

Correction values for​​ other calibrators for M2230 and M2340.
Type

Correction
Value

Calibration
Frequency

Calibration
Level

NTi Audio CAL200

-0.1

1 kHz

114 dB

B&K 4231

-0.2

1 kHz

114 dB

Norsonic Nor-1251

-0.2

1 kHz

114 dB293

Specifications

Actuator Correction
The following free-field 0° incidence corrections apply forcalibration using a protection grid actuator (e.g. B&K UA033,
GRAS RA0014). Please note, never touch the diaphragmof the measurement microphone capsule. The maximum
DC bias for the actuator calibration is 200 VDC.

M2211, M2215
NominalFrequency
[Hz]

M2211
[dB]

M2215
[dB]

31.5
63
125

0.0
0.0
0.0

0.0
0.0
0.0

250
500
1000

0.0
0.1
0.1

0.0
0.0
0.0

2000
4000
8000

0.6
1.7
4.2

0.2
1.2
3.9

12500
16000

7.3
9.2

6.7
9.0

294

M2230, M2340
The calibration requires the accessory Actuator Grid, NTi Audio# 600 040 112. The Actuator Grid comes with an insulation ring
dedicated for this measurement method.
NominalFrequency [Hz]M2230, M2340
[dB]

<400

0.0

400
500
630

-0.2
0.0
-0.2

800
1000
1250

0.0
0.0
-0.1

1600
2000
2500

0.2
0.2
0.3

3150
4000
5000

0.8
1.0
1.6

6300
8000
10000

2.4
3.6
4.8

12500
16000
20000

6.5
9.3
11.7

Specifications

Diffuse-field Sensitivity Level Correction
A diffuse sound field is characterized by the sound arriving at
the receiver from all directions with more or less equal probability. The M2230, M2340, M2211, M2215 and M4261 are
free-field equalized measurement microphones. The default
frequency response refers to a 0° sound incidence. The diffusefield sensitivity level correction is calculated by averaging thedirectional characteristics in accordance with IEC 61183. The
corrections ​​for diffuse-field conditions are documented in thefollowing table and may be activated directly on the XL2; see
Spectral Corrections. The directional response of the M2230 is
described in the appendix.
Example:• The sound pressure level in a diffuse sound field shall be
determined. The display of the XL2 with the M2230 reads
80.0 dBA for the 20 kHz third-octave band.
• The diffuse sound level is now calculated from the sumof the XL2 measurement value and the correction value(80.0 dB + 5.9 dB = 85.9 dB).

The diffuse-field sensitivity level correction is
not necessary using a diffuse field equalizedmeasurement microphone.

NominalFrequency[Hz]1/2” Microphone
M2230, M2340,
M2211, M2215[dB]

1/4” Microphone
M4261

<63
63
80

0.0
0.0
0.0

0.0
0.0
0.0

100
125
160

0.0
0.0
0.0

0.0
0.0
0.0

200
250
315

0.0
0.0
0.0

0.0
0.0
0.0

400
500
630

0.0
0.0
0.0

0.0
0.0
0.0

800
1000
1250

0.0
0.0
0.1

0.0
0.0
0.1

1600
2000
2500

0.2
0.2
0.4

0.1
0.1
0.2

3150
4000
5000

0.6
0.8
1.3

0.3
0.3
0.5

6300
8000
10000

1.8
2.5
3.4

0.8
1.1
1.6

12500
16000
20000

4.4
5.3
5.9

2.2
2.8
3.4

[dB]

295

Specifications

Free-field and Diffuse-Field Sensitivity for M2230 and M2340
1100

idealized
free-field-1-1

sensitivity relative [dB]

-2
-2
-3
-3
-4
-4

diffuse
field

-5
-5
-6
-6
-7
-7
-8
-8

10
10

20		

100				100

log frequency [Hz]

296

1000
1000

		

10000
10000

20000

Specifications

Spectral Correction for horizontal Sound Incidents using the Outdoor Microphone
The outdoor measurement microphone fulfills the requirements of IEC 61672 and ANSI S1.4 for vertical sound incidence.
For compliance with horizontal sound incidence a spectral correction is employed in the associated XL2 Sound Level Meter.

Spectral Correction for horizontal sound incidents:
NominalFrequency
[Hz]

WP30
Weather Protection
[dB]

WP61
Weather Protection[dB]

1/3 Octave

1/1 Octave

1/3 Octave

1/1 Octave

<800

0.0

0.0

0.0

0.0

800
1000
1250

0.0
0.0
0.1

0.0

0.0
0.0
0.0

0.0

1600
2000
2500

0.2
0.3
0.7

0.4

0.2
0.3
0.8

0.4

3150
4000
5000

1.3
2.0
2.7

2.0

1.4
2.1
2.5

2.0

6300
8000
10000

2.9
3.3
3.9

3.4

2.3
2.4
2.8

2.5

12500
16000
20000

4.6
6.4
6.8

5.9

3.0
3.1
3.1

3.0

Select Calibrate Menu: Show Spec Correction in the System Settings. This will enable the spectral correction field in
the Calibration menu.
297

Specifications

25. Technical Data PreAmplifier
MA220 PreAmplifier
Microphone PreAmplifier
Frequency Range (-3dB)
Residual Noise Floor typicalFrequency Response Flatness

MA230 PreAmplifier
with self-test (CIC)

Compatible with 1/2” microphone capsules type WS2F in accordance with IEC61094-4
4 Hz - 100 kHz

1.3 Hz - 50 kHz

1.9 mV(A) at C_in 15 pF ≙ 5.6 dBA @ 42 mV/Pa

2.4 mV(A) at C_in 15 pF ≙ 9.1 dBA @ 42 mV/Pa±0.2 dB

Phase Linearity
Maximum Output Voltage@ THD 3%, 1 kHz
Electronic Data Sheet

Impedance±0.1 dB, 10 Hz - 20 kHz< 1° @ 20 Hz - 20 kHz
21 Vpp ≙ 7,4 Vrms ≙ 138,9 dBSPL @ 42 mV/Pa

22 Vpp ≙ 7,8 Vrms ≙ 139,3 dBSPL @ 42 mV/Pa

Containing user calibration data; default factory sensitivity = 4.9 V/Pa
Read/write by XL2 Audio and Acoustic Analyzer
NTi Audio ASD in accordance with IEEE P1451.4 V1.0, Class 2, Template 27
Input: 20 GOhm // 0.26 pF, Output: 100 Ohm balanced

Power Supply

48 VDC phantom power, 2.3 mA typical

48 VDC phantom power, 0.8 mA typicalAttenuation< 0.17 dB (Rphantom 2x 6.8 kOhm)< 0.07 dB (Rphantom 2x 6.8 kOhm)

Connector

Balanced 3-pole XLR

Thread for Capsule

60 UNS2

WeightDimensions

90 g, 3.17 oz
Length 142.5 mm (5.6”), diameter 20.5 mm (0.8”)

Temperature Range-10°C to +50°C (14°F to 122°F)

Humidity
NTi Audio #5% to 90% RH, non-condensing
600 040 040

The product specifications may vary based on the mounted microphone capsule type.
298

600 040 200

Specifications

Appendix
Appendix 1: Standard - Optional Features

Standard Features

Optional

Sound Level Meter
Frequency Weighting-

Sound Level Meter
Time weighting• Extended Acoustic Pack:
ImpulseSound Exposure Level
Percentile Sound Pressure Levels for wide band, 1/1 and1/3 octave spectrum with flexible setting from 0.1% to99.9%.

Sound Level Meter
Correction-299

Appendix

Standard Features
Sound Level Meter
Parameter

Optional• Extended Acoustic Pack:
Clock-Impulse Maximum Level (Taktmaximalpegel) in accordance with DIN 45645-1:

Calculated levels in accordance with DIN 45645-1:

Impulsiveness in accordance with BS4142:2014 and
NordTest ACOU 112

Sound Level Meter
RTA Spectrum Analyzer

supported• Extended Acoustic Pack or Spectral Limits Option:
True peak level300

Appendix

Standard Features
Sound Level Meter
Audio Recording• Recording of wav-files(ADPCM compression)• Voice note recording

Sound Level Meter
Triggered Event Recording-

Sound Level Meter
Logging

supported

Optional• Extended Acoustic Pack:
Recording of wav-files (24 bit, 48 kHz)• Extended Acoustic Pack:FFT Analysis
Measurement Range• 100 ms logging• RTA logging of Lmin and Lmax
• Extended Acoustic Pack or Spectral Limits Option:with zoom function

FFT + Tol
Capture and Tolerance-• Spectral Limits:
Capture and Tolerance functionality

RT60

Octave band resolution• Extended Acoustic Pack:
1/3 octave band results

1/12 Oct + Tol-• Spectral Limits:
1/12 Oct + Tol
Capture and Tolerance functionality

301

Appendix

Standard Features

Optional

Noise Curves-• Spectral Limits Option

STIPA

-

• STIPA Option with STIPA functionality

Cinema Meter-• Cinema Meter Option

Querying measurement
data online via the USB
interface-

Remote Measurement Option supporting• Sound level meter and spectrum analyzer SLMeter/RTA• FFT analyzer• RT60 reverberation time
• Audio analyzer RMS/THD+N• High-resolution spectral analyzer 1/12 Oct + Tol

302

Appendix

Appendix 2: Factory Default Profiles
You may start up the XL2 with individual preset application profiles.

The profile Full mode is the default configuration with all available measurement functions enabled.

303

Appendix

DIN15905-5 / DIN15905-5 & Audio(Sound Level Monitoring in accordance with DIN15905-5)
The following limits apply at all areas accessible by the visitors
during the measurement period of 30 minutes:• Maximum averaged level = 99 dB
The XL2 displays this maximum level with the measurement result LAeq+k1.
• Maximum peak level LCpeak = 135 dB

These levels are shown in the numeric result page:
LAeq5”+k1

Time-averaged sound pressure level LAeq
with correction value k1 and a moving time
window of 5 seconds.

LAeq+k1

Time-averaged sound pressure level LAeq
with correction value k1.

LCpeak+k2

C-weighted peak level LCpeak with correction value k2.

The following sound levels are displayed in the real-time analyzer page:304

LZFhold3

For tracing of feedback frequencies. The
peak hold time is set to 3 seconds.

LZFlive

Actual real-time spectra.

Appendix

How to Measure• Select the page KSET with the rotary wheel.
• Measure the correction values k1 and k2 as described in thechapter Sound Level Meter: Correction Value KSET.
• Press the start button.
• The icon LOG flashes during the ongoing measurement. In
the case where the profile #DIN15905-5 & Audio has been
selected the icon AUD flashes, indicating the additional audio wav-file logging.
• During the measurement you can monitor the actual soundlevel LAeq5”+k1 in order to remain below the permitted limits; alternatively you may monitor the spectrum analyzer for
tracing possible feedback frequencies.
• Press stop
to finish the measurement.

In accordance with DIN15905-5, all sound levels are measured, displayed and logged to the
SD Card automatically. The settings are locked,
which ensures that the correct parameters aremeasured.
The profile #DIN15905-5 & Audio includes therecording of Compressed+AGC wav-files.

LimitsThis profile is configured with the following limits, which trigger
the lights on the limit button and external Digital I/O Adapter.
This facilitates a quick response to sound levels that exceed
these limits.

Measurement Results
You may import the log files into a report generator software based on MS Excel, providing automatically-completed
live event reports with noise level charts. The report generator software is a free download on the support website athttps://my.nti-audio.com for all registered XL2 customers.
305

Appendix

V-NISSG 100dB / V-NISSG 100dB&Audio(Sound Level Monitoring in accordance with V-NISSG)
The following limits apply at all areas accessible by the visitors
during the moving measurement period window of 60 minutes
during the live event:• Maximum averaged level
The XL2 displays this maximum level with the measurement
result LAeq60‘+k1.
Type oflive event

Max. level

Requirements

3

100 dB- Sound level recording- Results to store for 30 days
- Level warning to visitors- Hearing protection distributed- Chill out zone < 85 dB(A)

2

96 dB

- Sound level monitoring- Level warning to visitors- Hearing protection distributed

1

93 dB

- Sound level monitoring• Maximum peak level LAFmax = 125 dB

306

These levels are shown in the numeric result page:
LAeq5”+k1

Time-averaged sound pressure level LAeq
with correction value k1 and a moving time
window of 5 seconds.

LAeq60’+k1

Time-averaged sound pressure level LAeq
with correction value k1 and a moving time
window of 60 minutes.

LAFmax+k1

Maximum sound pressure level LAFmax
with correction value k1.

Appendix

The following sound levels are displayed in the real-time analyzer page:
LZFhold3

For tracing of feedback frequencies. The
peak hold time is set to 3 seconds.

LZFlive

Actual real-time spectra.

In accordance with V-NISSG, all sound levels
are measured, displayed and logged to SD Card
automatically. The settings are locked, which
ensures that the correct parameters are measured.
The profile #V-NISSG 100dB&Audio includes
the recording of Compressed+AGC wav-files.

How to Measure• Select the page KSET with the rotary wheel.
• Measure the correction value k1 as described in the chapter
Sound Level Meter: Correction Value KSET. (k2 is not requiredfor V-NISSG)• Press the start button.
• The icon LOG flashes during the ongoing measurement. In
the case where the profile #V-NISSG 100dB&Audio has
been selected the icon AUD flashes, indicating the additional
audio wav-file logging.
• During the measurement you can monitor the actual soundlevel LAeq5”+k1 in order to remain below the permitted limits; alternatively you may monitor the spectrum analyzer for
tracing possible feedback frequencies.
• Press stop
to finish the measurement.

307

Appendix

LimitsThis profile is configured with the following limits, which trigger the lights on the limit button and external Digital I/O Adapter. This facilitates a quick response to sound levels that exceed
these limits.

Appendix 3: Description Sound Levels

A-Frequency Weighting Filter in accordance withIEC 61672
Applicable for most common sound pressure levelmeasurements, compensating for human hearing
perception at lower sound pressure levels.
C-Frequency Weighting Filter in accordance withIEC 61672
Applicable for very high sound pressure levels,
compensating for human hearing perception athigh sound pressure levels; typically used for measurement of peak values, e.g. LCpeak

Measurement Results
You may import the log files into a report generator software based on MS Excel, providing automatically-completed
live event reports with noise level charts. The report generator software is a free download on the support website athttps://my.nti-audio.com for all registered XL2 customers.
308

CaptureThis selection offers the reference curve, which has
been previously stored with Capture in the spectrum analyzer of the SLMeter function.
Application example:• Comparing the performance of the left and rightspeakers in a live event sound setup.

Appendix

Sound Exposure Level
The sound exposure level LAE characterizes thetotal energy content of a signal and corresponds
to the LAeq normalized to one second. The soundexposure level is measured for example to compare
noise events with different time durations. The LAE
reports the amount of noise from an event such as
an individual aircraft fly-over. An earlier used level
name is SEL.
LAE = LAeq + 10 x log (time in seconds)
Time-Average Sound Level or
Equivalent Continuous Sound Level in accordance with IEC 61672
Octave-band Time-Average Sound Level or
Equivalent Continuous Sound Level in accordance with IEC 61672
with selectable 63 Hz or 125 Hz octave-band level
for low frequency noise monitoring; in case of a
selected 1/3 octave resolution in the RTA window,
these levels are calculated by summing the corresponding one-third-octave levels.

Moving Time-Average Sound Level orMoving Equivalent Continuous Sound Level
With selectable time window from one second
up to one hour, four individual levels can be configured. The moving time-average sound level is a
Leq based on a moving time window. This level isalso called “running Leq,T”, “gliding Leq,T” or “sliding Leq,T”.
The measurement result is updated every second
for the first 60 seconds. Afterwards the update rateis every five seconds. This is an example:

10h 00min 00sec

Start of XL2 measurement

10h 00min 05sec

Leq5” = Leq of the 5 seconds

10h 00min 06sec

Leq5” = Leq of the time window from 10h 00min 01sec to
10h 00min 06sec

10h 00min 07sec

Leq5” = Leq of the time window from 10h 00min 02sec to
10h 00min 07sec

309

Appendix

Application example:• Display the moving Leq over 5 seconds in accordance with DIN15905• Measure the moving Leq over 60 minutes in accordance with V-NISSG
Fast Time Weighting
Time constant t = 125 ms; the time weighting is
an exponential function of time, which defines
how changes of the instantaneous sound pressurelevel are averaged for useful sound pressure level
results. The measurement results are shown accurately for sound sources with a minimum length of
0.5 seconds. The decay rate is 34.7 dB/s. Fast timeweighting is typically used for common sound levelmeasurements.
Holding Maximum Level
For tracing of feedback frequencies in the RTA page.
The hold time can be set to 3, 5 or 10 seconds.

310

Impulse Time Weighting
Time constant attack t = 35 ms; time constant decay t = 1500 ms; the time weighting is an exponential function of time, which defines how changesof the instantaneous sound pressure level are averaged for useful sound pressure level results. The
measurement results are shown accurately forsound sources with a minimum length of 0.1 seconds. Impulse time weighting is used for impulsive
sound sources.
Impulse Penalty ImpPenalty
Impulsive penalty in accordance with BS4142:2014
and NordTest ACOU 112. The LAF is sampled witha time interval of 12 ms. The penalty is calculated
as follows:
Penalty KI= 1.8 * (Prominence P - 5) for P > 5
P=3*lg(onset rate[dB/s]) + 2*lg(level difference[dB])
The Prominence P is designed to give a maximum
around 15; concluding the maximum impulse penalty is 18 dB.

Appendix

Correction Value k1
The correction value k1 is based on an LAeq measurement. It is measured or manually set in thepage KSET of the sound level meter function.
Correction Value k2
The correction value k2 is based on either LCeq or
LCpeak measurement. It is measured or manually
set in the page KSET of the sound level meter function.
Parameter live
Actual current sound pressure level.
Parameter max
Maximum sound level of the measurement cycle.
Parameter min
Minimum sound level of the measurement cycle.
Correction Value off
No correction value, default setting.

Peak Level
Application example:
Measure LCpeak in accordance with DIN15905
The RTA spectrum analyzer measures the true peaklevel with the optional Extended Acoustic Pack. The
peak hold time can be set to 0, 1 or 5 seconds.
Percentile Sound Level - Level Statistics
The statistical distribution of sound pressure levels
is commonly used for environmental noise analysis, such as road traffic or community noise assessments. For example, LAFxx% is the noise levelexceeded during xx% of the measurement period;e.g., LAF90% is the noise level exceeded during
90% of the measurement period.
Please see the specifications at chapter Technical
Data XL2: Functions of Extended Acoustic Pack
(optional) in this manual.
Previous Level
Applicable for timer mode Repeat or Repeat Synchronized; displays the selected sound pressurelevel of the last measurement cycle.

311

Appendix

Slow Time Weighting
Time constant t = 1 second; the time-weighting is
an exponential function of time, which defines howchanges of the instantaneous sound pressure level
are averaged for useful sound level results. The decay rate is 4.3 dB/s.
Parameter T3
Clock-Impulse Maximum Level (Taktmaximalpegel)
LAFT3 in accordance with DIN 45645-1; maximum
sound pressure level measured with frequency
weighting A and time weighting F within a time interval of 3 seconds.
Parameter T3eq
Time-average Clock-Impulse Maximum Level(Taktmaximalpegel) LAFT3eq in accordance with
DIN 45645-1 and DIN 45657.
Parameter T5
Clock-Impulse Maximum Level (Taktmaximalpegel)
LAFT5 in accordance with DIN 45645-1; maximum
sound pressure level measured with frequency
weighting A and time weighting F within a time interval of 5 seconds.

312

Parameter T5eq
Time-average Clock-Impulse Maximum Level(Taktmaximalpegel) LAFT5eq in accordance with
DIN 45645-1 and DIN 45657.
Inverted X-Curve
In the film and recording industry an X curve is also
known as a wide-range curve, e.g., used for cinema
installations conforming to SMPTE ST 202:2010 or
ISO 2969:2015 @ 500 seats.
Z-frequency weighting in accordance withIEC 61672 (= flat frequency response, no filter)
Overall sound pressure level, all sound signal components are included; required for special applications.
Sound Pressure Level Lp
Lp is a commonly used abbreviation for sound pressure level (p for pressure); for example, Lw is used
for Sound Power Level

Appendix

Appendix 4: Common Sound Levels

Display

Application

LAE

Sound Exposure Level
The sound exposure level LAE characterizes the total energy
content of a signal and corresponds to the LAeq normalized to
one second. The sound exposure level is measured for example
to compare noise events with different time durations. The LAE
reports the amount of noise from an event such as an individual
aircraft fly-over. An earlier used level name is SEL.
LAE = LAeq + 10 x log (time in seconds)

LAeq

Time-Average Sound Pressure Level or
Equivalent Continuous Sound Pressure Level
Averaged sound level over time with A frequency weighting.

LAeq_dt

Level LAeq_dt “delta t” in report
Level of the preset logging interval in the LOG-menu; e.g. Logging interval = 1 second, then LAeq_dt is the time averaged levelof the past 1 second.

Setting
->

->

->

313

Appendix

LAeq+k1

Time-Average Sound Pressure Level with Correction Value
The actual measurement position often differs to the loudest position of the live event. Thus, the correction value k1 is the correction value of LAeq between the loudest position and the actual
measurement position, measured using pink noise. The correction value k1 is measured or manually set in the page KSET of thesound level meter function.

LAeqxxMoving Time-Average Sound Pressure Level
Measurement of the moving sound level over time Leq with Aweighting frequency and F-weighting time responses; the parameter xx is user-defined from one second up to one hour. This levelis also called “running Leq,T”, “gliding Leq,T” or “sliding Leq,T”.

->

->

->

->

Four individual levels can be configured, e.g.
• 5 seconds for live sound monitoring• 10 minutes (in accordance with the French standard)• 15 minutes (in accordance with the British standard)• 60 minutes (in accordance with V-NISSG)
LAeq20-200

314Time-Average Sound Pressure Level 20 - 200 Hz
Summed time-averaged sound pressure level over time with
A frequency weighting of the third-octave frequency bands
20 - 200 Hz.

->->

Appendix

LAeq60’+k1

Moving Time-Average Sound Pressure Level with
Correction Value k1
The actual measurement position often differs to the loudest position of the live event. Thus, the correction value k1 is the correction value of LAeq60’M between the loudest position and theactual measurement position, measured using pink noise. The
correction value k1 is measured or manually set in the page KSETof the sound level meter function.
Application: Measurements in accordance with V-NISSG

LAF

Actual Sound Pressure Level
Sound pressure level with A frequency weighting and F timeweighting, compensating for human hearing perception at lower
sound pressure levels; applicable at levels lower than 100 dB.

LAFmaxMaximum Sound Pressure Level
Measures the maximum environmental noise level during themeasurement period.

LAFmax_dt

Maximum Sound Pressure Level “delta t” in report
Maximum level of the preset logging interval in the LOG-menu,
e.g. 1 second.

LAFminMinimum Sound Pressure Level
Measures the minimum environmental noise level during themeasurement period.

->

->

->

->

->

->

->

->

->

->

315

Appendix

LAFmin_dt

Minimum Sound Pressure Level “delta t” in report
Minimum level of the preset logging interval in the LOG-menu,
e.g. 1 second.

LAFxx%

Percentile Sound Pressure Level
The statistical distribution of sound pressure levels is commonlyused for environmental noise analysis, such as road traffic or community noise assessments. For example LAFxx% is the noiselevel exceeded during xx% of the measurement period; e.g.,
LAF90% is the noise level exceeded during 90% of the measurement period.
Please see the specifications at chapter Technical Data XL2: Functions of Extended Acoustic Pack (optional) in this manual.
Sound Level [dB] vs Time
LAF10% = 88.8dB

90

LAeq= 84.2dB
80

LAF50%= 76.4dB

70
LAF90%= 66.6dB
60

316Time [seconds]->->

Appendix

LCeq

Time-Average Sound Pressure Level or
Equivalent Continuous Sound Pressure Level
Averaged sound level over time with C frequency weighting.

LCPK

Peak Sound Level
Peak sound level with C frequency weighting. Measures the peaklevel. High peak levels can damage the human hearing.

LCPKmax

Maximum Peak Sound Level
Maximum peak sound level with C frequency weighting. Measures the peak level. High peak levels can damage the humanhearing.

LCPK_dt

Maximum Peak Sound Level „delta t” in report
Maximum peak sound level with C frequency weighting of thepreset logging interval in the LOG-menu, e.g. 1 second.

LCPK+k2

Peak Sound Level with Correction Value
The actual measurement position often differs to the loudest position of the live event. Thus, the correction value k2 is the correction value of LCPK between the loudest position and the actual
measurement position, measured using pink noise. The correction value k2 is measured or manually set in the page KSET of thesound level meter function.

->

->

->

->

->

->

->

->

->

317

Appendix

LEX

Noise Exposure Level LEX
The Noise at Work Directive 2003/10/EC lays down minimum requirements for the protection of workers from risks to their healthand safety arising or likely to arise from exposure to noise and inparticular the risk to hearing.
• Steady noise LEX,8h = LAeq: (applies to LAS, deviation < 5 dB)
LAeq measured over a short time equals LEX,8h; the following
formula applies for a measurement period < 8 hours:
LEX,8h = LAeq + 10 x log ( T / 8 hours )• Steady noise with stepped level variations:
Measure LAeq at the different levels and enter the data withthe corresponding exposure time in the NTi Audio noise exposure level post-processing form; the LEX,8h will be calculated
and displayed.
• Varying noise levels:
LEX,8h = LAeq measured for 8 hours->->

The exposure limit values and respective actions are:

318

LEX, 8h

LCpeakActionLower limit value

80 dB(A)135 dBThe employer shall make individual hearing protectors available
to workers

Upper limit value

85 dB(A)137 dB

Hearing protectors shall be used

Exposure limit

87 dB(A)140 dB

The attenuation characteristics of the hearing protectors worn
must adequately reduce the levels below this limit

Appendix

Appendix 5: Vibration Meter Functions
Acceleration ain units m/s2, g, in/s2, dB
La [dB] = 20*log (a / 10-6)
Velocity v
in units m/s, in/s and dB;
Velocity is calculated based on the acceleration aand the frequency f: v = a / (2 * π * f)
Lv [dB] = 20*log (v / 10-9)
Displacementin units m, in, dB;
Displacement is calculated based on the acceleration a and the frequency f: d = a / (2 * π * f)2
Ld [dB] = 20*log (d / 10-12)
RMS level
Measurement result is based on RMS
Peak level
Measurement result is based on peak level• Peak level a(Pk) = √2 * a• Peak level v(Pk) = √2 * v• Peak level d(Pk) = √2 * d

Peak-peak Level
Measurement result is based on peak-peak level• Peak-peak level a(PP) = a(Pk) * 2• Peak-peak level v(PP) = v(Pk) * 2• Peak-peak level d(PP) = d(Pk) * 2
Moving Time-Average Level orMoving Equivalent Continuous Level
with selectable time window 1, 2, 4 or 8 seconds.

Clock-Impulse Maximum Level(Taktmaximalpegel)
Maximum velocity during a periodic 30 seconds
interval with time weighting F in accordance with
DIN 4150-2.
Peak Particle Velocity PPV
Ground or blast vibration amplitude is often measured as particle velocity or the speed at which aparticle vibrates. This is quantified as peak particle
velocity PPV in the units [mm/s] or [in/s]. PPV
equals the level type vel Pk on the XL2.

319

2000 dt 11.21

Appendix

Details IEC 61672 & IEC 61260
The XL2-TA Analyzer, with the M2230 measurement microphone, fully complies with the standards IEC 61672:2013,
IEC 61672:2003, IEC 61260:2014 and IEC 61260:2003 as anintegrating class 1 Sound Level Meter with A, C, Z frequency
weighting and fast/slow time weighting. The impulse timeweighting is optionally available with the Extended Acoustic
Package.
The type approval applies to the sound level meter in accordance with IEC 61672 and the Octave/Third-Octave measurement in accordance with IEC 61260. Attention should be given
to the following recommendations on the environment and theconfiguration.
Environment
Persons and objects that are located in the sound field during
the measurement have an absorbing, reflecting or shielding
impact on the sound field and may therefore compromise themeasurement result. Consequently, such objects should be removed from the sound field where appropriate. The measurement microphone should be mounted on a tripod. The operator
should remain as far away as possible behind the microphone
during the measurement.
322

Configuration “Microphone Detached”• XL2-TA Sound Level Meter- Hardware version: D2, E0, E1- Firmware version 4.71
• M2230 Measurement Microphone, consisting of- Microphone Preamplifier MA220- Microphone Capsule MC230 or MC230A• M2340 Measurement Microphone, consisting of- Microphone Preamplifier MA230- Microphone Capsule MC230A• ASD Cable, 5 meter or 10 meter or 20 meter• Class 1 Sound Calibrator CAL200• Optional- Optional: Extended Acoustic Pack
- NTi Audio Mains Power Adapter Exel Line- NTi Audio Microphone Clamp MH01
- NTi Audio Windscreen, 50 mm- NTi Audio Windscreen, 90 mm- XL2 Input KeypadWith the microphone connected by the ASD Cable, the analyzer can be held in your hand during the measurement. This
offers the convenience of watching the measurement values
as they occur.

Appendix

Configuration “Microphone Attached”• XL2-TA Sound Level Meter- Hardware version: D2, E0, E1- Firmware version 4.71
- Shroud MXA01• M2230 Measurement Microphone, consisting of- Microphone Preamplifier MA220- Microphone Capsule MC230 or MC230A• M2340 Measurement Microphone, consisting of- Microphone Preamplifier MA230- Microphone Capsule MC230A• Class 1 Sound Calibrator CAL200• Optional- Optional: Extended Acoustic Pack
- NTi Audio Mains Power Adapter Exel Line- NTi Audio Windscreen, 50 mm- NTi Audio Windscreen, 90 mm- XL2 Input Keypad

There are no correction values required forthese configurations.

Configuration “Outdoor Microphone Detached”• XL2-TA Sound Level Meter- Hardware version: D2, E0, E1- Firmware version 4.71
• M2230 Measurement Microphone, consisting of- Microphone Preamplifier MA220- Microphone Capsule MC230 or MC230A• M2340 Measurement Microphone, consisting of- Microphone Preamplifier MA230- Microphone Capsule MC230A• Weather Protection WP30 with bird spike BS01
• ASD Cable, 5 meter or 10 meter or 20 meter• Class 1 Sound Calibrator CAL200• Optional- Optional: Extended Acoustic Pack
- NTi Audio Mains Power Adapter Exel Line- XL2 Input Keypad- Dehumidifier for Weather Protection WP30

• There are no correction values required forthe configuration “Outdoor Microphone Detached” at vertical noise incidents.
• Activate the corresponding correction in the
Calibration menu for “Outdoor Microphone
Detached” at horizontal noise incidents.
323

Appendix

General Information
Reference Sound Pressure Level
The reference sound pressure level is 114 dBSPL relative to
20 mPa.
Reference Level Range
The reference level range is MID, 20 - 120 dBSPL
Reference Orientation
The microphone reference point is located in the middle of the
microphone membrane. The 0° reference orientation and theorientation of the membrane’s surface normal is identical.
Verified Frequency Range
20 Hz to 20 kHz
Greatest Peak-To-Peak Voltage at the Electric Input(Refer IEC61672-1 paragraphs 5.1.16, 9.3.i)
The highest sound pressure level at the M2230 microphonewith a sensitivity of S = 42 mV/Pa is 143.5 dB.
Initial Time Interval after Power On (IEC61672-1, 5.1.18)
The XL2-TA Sound Level Meter and M2230 microphone meetthe given specifications for the electro-acoustical response after an initial time interval of no more than one minute following
324

switching on the power. This assumes that the devices havebeen allowed to reach equilibrium with the prevailing ambientenvironment before switching on the power.
Insertion of Electrical Signals(Refer IEC61672-1 paragraphs 5.1.15, 9.3g)
The capsule replacement NTI-K65-15 can be used to insert
electrical signals to the preamplifier MA220. The device provides at one side a contact that corresponds to the center contact of the replaced microphone capsule, at the other side a
BNC-plug for the electrical signals. The impedance at the output of the device is 15 pF with a maximum deviation of ±1 pF.
The electrical noise floor is measured by shorting the contacts of the BNC plug. Before the NTI-K65-15 can be mounted to the preamplifier MA220, the microphone capsule mustfirst be detached. The nominal sensitivity S of the capsule isS = 42 mV/Pa. Measurements with the NTI-K65-15 therefore
require that the sensitivity in the calibration menu is manually
adjusted to S = 42 mV/Pa.
The maximum electrical input voltage is 36 Vpp. The attenuation between the device and the XLR input of the XL2-TA is
0.78 dB at a reference frequency of 1 kHz. A 1 kHz signal with
459 mVrms level is required at the input of the device, to substitute the signal of a microphone capsule with the sensitivity
42 mV/Pa at a reference level of 114 dBSPL.

Appendix

Output (Refer IEC61672-1 paragraphs 5.16.1, 9.2.5p)
The instrument provides no electrical analog or digital outputs
for measurements.
Typical Time Interval Needed to Stabilize after Changes inEnvironmental Conditions (IEC61672-1, 6.1.2, 9.3l)
Recommended time interval for stabilizing the sound level meter after changes in environmental conditions, prior to performing any measurements:

Change in the environmental condition

Time Interval

Temperature±5 °C

15 minutes

Temperature±20 °C

30 minutes

Air pressure±5 kPa15 seconds

Humidity±30%

15 minutes

No Limit on Operational Environment(Refer IEC61672-1 paragraphs 6.3.2, 9.2.7a)
There are no restrictions in place for parts or components,
which would limit the operational environment.
Exposure to Electrostatic Discharges(Refer IEC61672-1 paragraphs 6.5.2, 9.2.7b)
Heavy electrostatic discharges directly to the instrument’s
connector or keyboard may interrupt the operation. The XL2-TA
either switches off or freezes at the last valid measurement
value. In such a case re-start the instrument. If the data logging
had been active prior the interrupt, the log file may contain agap. However, the acquired results can be identified correctly as each one is saved together with its own individual timestamp.
Exposure to AC Power and Radio Frequency Fields(Refer IEC61672-1 paragraphs 6.6.1, 9.2.7c)
The sound level meter complies with the requirements of thestandards IEC61672-1:2013 and IEC61260-1:2014 regarding
immunity against high frequency fields or mains power fields
from 50 to 60 Hz.

The time intervals apply, for instance, after moving from a cold
into a warm room, and assume that combinations of air temperature and relative humidity do not yield a dew point greaterthan +39 °C or less than –15 °C.
325

Appendix

Impact of Electromagnetic Fields
If the device is exposed to electromagnetic fields of 10 V/m,
the measurement of sound levels below 74 dB is not specified. If the electromagnetic fields exceed 10 V/m, the exposed
instrument is not specified in any level range.
Susceptibility to AC Power and Radio Frequency Fields(Refer IEC61672-1 paragraphs 6.6.3, 9.3o)
The device has the greatest susceptibility to AC power frequency fields, if the direction of the magnetic field is the sameas the orientation of the microphone axis.
The device has the greatest susceptibility to radio frequency
fields in the lowest measurement range, if the surface normalof the display and the direction of the incoming radio frequency
field are parallel to each other and the power supply is connected. In this case, the sound level meter should be operated
without a power supply. The configuration with the greatest
radio-frequency emissions levels is provided by connecting themains power adapter to the sound level meter.
Measuring Low-Level Sound Fields(Refer IEC61672-1 paragraphs 5.6.5, 9.2.5d)
If the sound level is very low, the measurement result is affected by the noise floor of the sound level meter. The specified configuration complies with class 1 within the given linear
measuring range.
326

Influence of the ASD Cable(Refer IEC61672-1 paragraphs 7.1, 9.2.6b)
The ASD Cable serves as connection cable between the
XL2-TA sound level meter and the microphone in the detachedconfiguration. There are no correction values required for thisconfiguration.
Influence of Mechanical Vibrations
Mechanical vibrations with 1 m/s2 acceleration perpendicular
to the membrane of the microphone, will raise the lower limitof the linear operating range to 71 dB (A-weighted) for the frequencies 31,5 Hz, 63 Hz, 126 Hz, 250 Hz, 500 Hz, 630 Hz,
800 Hz and 1000 Hz. Mechanical vibrations with 1 m/s2 acceleration parallel to the membrane of the microphone, will raise
the lower limit of the linear operating range to 68 dB (A-weighted) for the frequencies 31,5 Hz, 63 Hz, 126 Hz, 250 Hz, 500 Hz,
630 Hz, 800 Hz and 1000 Hz.
Modes of Operation and Accessories
The greatest susceptibility to radio frequency fields is independet of operation mode or connected accessories.
Volume of Measurement Microphone M2230• Equivalent Diaphragm Volume = 50 mm3• Volume between grid and membran/housing = 92.5 mm3• Calibrator Load Volume = 142.5 mm3

Appendix

Class 1 Sound Calibrator

Accessory(Refer IEC61672-1 paragraphs 5.2.1, 5.2.7, 9.3d)

Input Keypad
The Input Keypad has no effect on measured sound pressurelevels of the instrument.

If an obligatory calibration is required for the sound level meter,in accordance with the type approval, then the Class 1 Sound
Calibrator CAL200 should be used.
Technical Details• Type: Larson Davis CAL200• Level correction: -0.1 dB• Calibration frequency: 1 kHz (= reference frequency)• Calibration level: 114 dB (= reference sound pressure level)
Details for Calibration
The calibration has to be executed according to the instructions
given in chapter “Calibration”. Ensure that the calibrator is set
to 114 dB.
Add the free-field correction values to the reference soundpressure level, and enter the result into the XL2-TA under “Calibration Level“.

327Appendix

Level Linearity(Refer IEC61672-1 paragraphs 5.5.3, 5.5.9, 9.2.2e, 9.3e, 9.3f).
All values refer to Sref = 42 mV/Pa*. The starting levels for thelevel linearity tests are listed in the following tables:

Level range: Low

LAt*

[dB]

31,5 fromto
Hz starting

LCt*

Level range: Mid
Frequency
LAeqT*

LZt*

24 from
27 from
30 from
68 to
105 to108 to54 starting 94 starting 94 starting

LAE*

LCpeak*

LAt*

[dB]

(tint = 10s)
24 from
68 to
54 starting

34
78
54

from

24 from
27 from
30 from
24 from
34 from
108 to108 to108 to108 to118 tostarting 94 starting 94 starting 94 starting 94 starting 104

1 kHz tofrom

24 from
27 from
30 from
24 from
34
109 to107 to108 to109 to119
starting 94 starting 94 starting 94 starting 94 starting 104

4 kHz tofrom

24 from
27 from
30 from
24 from
34
107 to105 to108 to107 to117
starting 94 starting 94 starting 94 starting 94 starting 104

31,5 fromto
Hz starting
41
111

LCt*

Frequency
LAeqT*

LZt*

31 from
32 from
35 from
86 to
123 to126 to54 starting 114 starting 114 starting

LAE*(tint = 10s)

31 from
86 to
54 starting

41
96
54

from

31 from
32 from
35 from
31 from
41 from
126 to126 to126 to126 to136 tostarting 114 starting 114 starting 114 starting 114 starting 124

1 kHz tofrom

31 from
32 from
35 from
31 from
41
127 to126 to126 to127 to137
starting 114 starting 114 starting 114 starting 114 starting 124

4 kHz tofrom

31 from
32 from
35 from
31 from
41
126 to123 to126 to126 to135
starting 114 starting 114 starting 114 starting 114 starting 124

8 kHz to8 kHz to24 from
27 from
30 from
24 from
34
12,5 fromto104 to102 to108 to104 to114
kHz starting 94 starting 94 starting 94 starting 94 starting 104

31 from
32 from
35 from
31 from
41
12,5 fromto122 to120 to126 to122 to132
kHz starting 114 starting 114 starting 114 starting 114 starting 124* If the sensitivity Sx deviates from the given data, a correction value of 20*log(Sref/Sx) has to be added.
Example: Sx = 45 mV/Pa -> correction value = 20*log(42/45) = -0.6 dB
328

LCpeak*38
129

Appendix

Level range: High

LAt*

[dB]

31,5 fromto
Hz starting

LCt*

Frequency
LAeqT*

LZt*

53 from
51 from
56 from
98 to
137 to137 to94 starting 114 starting 114 starting

LAE*

LCpeak*(tint = 10s)
53 from
63
98 to
108
94 starting 94

from

53 from
51 from
56 from
53 from
63 from
137 to137 to137 to137 to147 tostarting 114 starting 114 starting 114 starting 114 starting 124

1 kHz toSound pressure levels, which continiously exceed the specified
linear measurement range and overload the microphone preamplifier, may cause in extreme cases a displayed level below theactual sound pressure level.

65
140

from

53 from
51 from
56 from
53 from
63
138 to137 to137 to138 to148
starting 114 starting 114 starting 114 starting 114 starting 124

4 kHz tofrom

53 from
51 from
56 from
53 from
63
136 to137 to137 to136 to146
starting 114 starting 114 starting 114 starting 114 starting 124

8 kHz to53 from
51 from
56 from
53 from
63
12,5 fromto133 to131 to137 to133 to143
kHz starting 114 starting 114 starting 114 starting 114 starting 124

329

Appendix

Level Linearity of Octaveband-Spectrumin accordance with IEC 61260.
All values refer to Sref = 42 mV/Pa*.
NominalFrequency
Hz

Level Range
LOW

MID

HIGH

20

45-108 dB

20-126 dB

32-137 dB

31.5

25-108 dB

20-126 dB

32-137 dB

63

23-108 dB

20-126 dB

32-137 dB

125

14-108 dB

17-126 dB

33-137 dB

250

13-108 dB

15-126 dB

34-137 dB

500

13-108 dB

15-126 dB

36-137 dB

1000

15-108 dB

16-126 dB

39-137 dB

2000

17-108 dB

18-126 dB

41-137 dB

4000

19-108 dB

20-126 dB

44-137 dB

8000

19-108 dB

23-126 dB

47-137 dB

16000

18-108 dB

28-126 dB

51-137 dB

The sampling rate of the filters is 48 kHz.

* If the sensitivity Sx deviates from the given data, a correction value of
20*log(Sref/Sx) has to be added.
Example: Sx = 45 mV/Pa -> correction value = 20*log(42/45) = -0.6 dB
330

Appendix

Level Linearity of Third-Octaveband-Spectrumin accordance with IEC 61260.
All values refer to Sref = 42 mV/Pa*.

NominalFrequency
Hz

Level Range
LOW

MID

HIGH

12.5
16
20

48-108 dB
46-108 dB
43-108 dB

17-126 dB
17-126 dB
17-126 dB

29-137 dB
29-137 dB
29-137 dB

25
31.5
40

41-108 dB
37-108 dB
28-108 dB

16-126 dB
15-126 dB
14-126 dB

50
63
80

23-108 dB
19-108 dB
11-108 dB

100
125
160

NominalFrequency
Hz

Level Range
LOW

MID

HIGH

1600
2000
2500

11-108 dB
13-108 dB
13-108 dB

12-126 dB
13-126 dB
14-126 dB

35-137 dB
36-137 dB
37-137 dB

29-137 dB
29-137 dB
29-137 dB

3150
4000
5000

14-108 dB
14-108 dB
15-108 dB

14-126 dB
15-126 dB
16-126 dB

38-137 dB
39-137 dB
40-137 dB

13-126 dB
12-126 dB
11-126 dB

29-137 dB
29-137 dB
29-137 dB

6300
8000
10000

15-108 dB
15-108 dB
15-108 dB

17-126 dB
18-126 dB
19-126 dB

41-137 dB
42-137 dB
43-137 dB

9-108 dB
8-108 dB
8-108 dB

11-126 dB
10-126 dB
10-126 dB

29-137 dB
29-137 dB
29-137 dB

12500
16000
20000

14-108 dB
13-108 dB
13-108 dB

21-126 dB
23-126 dB
26-126 dB

44-137 dB
48-137 dB
50-137 dB

200
250
315

8-108 dB
7-108 dB
8-108 dB

10-126 dB
10-126 dB
10-126 dB

29-137 dB
29-137 dB
30-137 dB

400
500
630

8-108 dB
8-108 dB
9-108 dB

11-126 dB
11-126 dB
11-126 dB

30-137 dB
31-137 dB
31-137 dB

800
1000
1250

9-108 dB
10-108 dB
11-108 dB

11-126 dB
11-126 dB
12-126 dB

32-137 dB
34-137 dB
35-137 dB

The sampling rate of the filters is 48 kHz.

* If the sensitivity Sx deviates from the given data, a correction value of
20*log(Sref/Sx) has to be added.
Example: Sx = 45 mV/Pa -> correction value = 20*log(42/45) = -0.6 dB

331

Appendix

Self-generated Noise with Microphone(Refer IEC61672-1 paragraphs 5.6.1 to 5.6.4, 9.2.5o)
Self-generated noise with electrical input device @ S = 42 mV/Pa
Level range [dB]

Frequencyweighting

low

mid

high

Z

22

23

46

A

11

19

43

C

14

18

42

Self-generated noise with M2230 microphone @ S = 42 mV/Pa
Level range [dB]

Frequencyweighting

low

mid

high

Z

23

25

46

A

17

21

43

C

20

22

42

The averaging time is 30 seconds for all measurements.

332

Appendix333Appendix

Frequency Response Corrections(Refer IEC61672-1 paragraphs 5.2.4, 5.2.5, 5.2.6 und 9.2.4d)
The below listed wind screen corrections may be selected in the XL2 Sound Level Meter.
The listed uncertainty applies for all here listed measurements and corrections. Its calculated for a level of confidence of 95% witha coverage factor k=2. It represents the maximum permitted expanded uncertainty in accordance with IEC 62585.

NominalFrequency

Hz

334

ActualFrequency

0° Free-field
Frequency
Response

0° Free-field
Correction

Housing Reflection
and Microphone
Diffraction
Correction

Impact of
50 mm
Wind
Screen0° Free-field
Correction with
50 mm
Wind Screen

Impact of
90 mm
Wind
Screen0° Free-field
Correction with
90 mm
Wind Screen

Measurement
Uncertainty

Hz

dB

dB

dB

dB

dB

dB

dB

dB

63

63.10

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.20

125

125.89

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.20

250

251.19

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.20

315

316.23

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.20

400

398.11

0.0

0.0

0.0

0.0

0.0

0.1

-0.1

0.20

500

501.19

0.0

0.0

0.0

0.0

0.0

0.1

-0.1

0.20

630

630.96

0.0

0.0

0.0

0.0

0.0

0.1

-0.1

0.20

800

794.33

0.0

0.0

0.0

0.0

0.0

0.2

-0.2

0.20

1000

1000.00

0.0

0.0

0.0

0.0

0.0

0.2

-0.2

0.20

1060

1059.25

0.0

0.0

0.0

0.0

0.0

0.2

-0.2

0.20

1120

1122.02

0.0

0.0

0.0

0.1

-0.1

0.2

-0.2

0.20

1180

1188.50

0.0

0.0

0.0

0.1

-0.1

0.2

-0.2

0.20

1250

1258.93

0.0

0.0

0.0

0.1

-0.1

0.2

-0.2

0.20

Appendix

NominalFrequency

ActualFrequency

0° Free-field
Frequency
Response

0° Free-field
Correction

Housing Reflection
and Microphone
Diffraction
Correction

Impact of
50 mm
Wind
Screen0° Free-field
Correction with
50 mm
Wind Screen

Impact of
90 mm
Wind
Screen0° Free-field
Correction with
90 mm
Wind Screen

Measurement
Uncertainty

1320

1333.52

0.0

0.0

0.0

0.1

-0.1

0.2

-0.2

0.20

1400

1412.54

0.0

0.0

0.0

0.1

-0.1

0.2

-0.2

0.20

1500

1496.24

0.0

0.0

0.0

0.1

-0.1

0.3

-0.3

0.20

1600

1584.89

0.0

0.0

0.0

0.1

-0.1

0.3

-0.3

0.20

1700

1678.80

0.0

0.0

0.0

0.1

-0.1

0.3

-0.3

0.20

1800

1778.28

0.0

0.0

0.0

0.1

-0.1

0.3

-0.3

0.20

1900

1883.65

0.0

0.0

0.0

0.2

-0.2

0.3

-0.3

0.20

2000

1995.26

0.0

0.0

0.0

0.2

-0.2

0.3

-0.3

0.20

2120

2113.49

0.0

0.0

0.0

0.2

-0.2

0.3

-0.3

0.20

2240

2238.72

0.0

0.0

0.0

0.2

-0.2

0.3

-0.3

0.20

2360

2371.37

0.0

0.0

0.0

0.3

-0.3

0.3

-0.3

0.20

2500

2511.89

0.0

0.0

0.0

0.3

-0.3

0.2

-0.2

0.20

2650

2660.73

0.0

0.0

0.0

0.3

-0.3

0.1

-0.1

0.20

2800

2818.38

0.0

0.0

0.0

0.3

-0.3

0.1

-0.1

0.20

3000

2985.38

0.0

0.0

0.0

0.4

-0.4

0.0

0.0

0.20

3150

3162.28

0.0

0.0

0.0

0.4

-0.4

-0.1

0.1

0.20

3350

3349.65

0.0

0.0

0.0

0.4

-0.4

-0.2

0.2

0.20

3550

3548.13

0.0

0.0

0.0

0.5

-0.5

-0.2

0.2

0.20

3750

3758.37

0.0

0.0

0.0

0.5

-0.5

-0.2

0.2

0.20

4000

3981.07

0.0

0.0

0.0

0.5

-0.5

-0.2

0.2

0.20

4250

4216.97

0.0

0.0

0.0

0.6

-0.6

-0.1

0.1

0.30

335

Appendix

NominalFrequency

ActualFrequency

0° Free-field
Frequency
Response

0° Free-field
Correction

Housing Reflection
and Microphone
Diffraction
Correction

Impact of
50 mm
Wind
Screen0° Free-field
Correction with
50 mm
Wind Screen

Impact of
90 mm
Wind
Screen0° Free-field
Correction with
90 mm
Wind Screen

Measurement
Uncertainty

4500

4466.84

0.0

0.0

0.0

0.6

-0.6

-0.1

0.1

0.30

4750

4731.51

0.0

0.0

0.0

0.6

-0.6

-0.1

0.1

0.30

5000

5011.87

0.0

0.0

0.0

0.6

-0.6

-0.1

0.1

0.30

5300

5308.84

0.0

0.0

0.0

0.5

-0.5

-0.2

0.2

0.30

5600

5623.41

0.0

0.0

0.0

0.5

-0.5

-0.3

0.3

0.30

6000

5956.62

0.0

0.0

0.0

0.4

-0.4

-0.4

0.4

0.30

6300

6309.57

0.0

0.0

0.0

0.3

-0.3

-0.4

0.4

0.30

6700

6683.44

0.0

0.0

0.0

0.3

-0.3

-0.4

0.4

0.30

7100

7079.46

0.0

0.0

0.0

0.2

-0.2

-0.3

0.3

0.30

7500

7498.94

0.0

0.0

0.0

0.1

-0.1

-0.3

0.3

0.30

8000

7943.28

0.0

0.0

0.0

0.1

-0.1

-0.3

0.3

0.30

8500

8413.95

0.0

0.0

0.0

0.1

-0.1

-0.4

0.4

0.45

9000

8912.51

0.0

0.0

0.0

0.1

-0.1

-0.5

0.5

0.45

9500

9440.61

0.0

0.0

0.0

0.1

-0.1

-0.6

0.6

0.45

10000

10000.00

0.0

0.0

0.0

0.1

-0.1

-0.5

0.5

0.45

10600

10592.54

0.0

0.0

0.0

0.1

-0.1

-0.6

0.6

0.45

11200

11220.18

0.0

0.0

0.0

0.1

-0.1

-0.7

0.7

0.45

11800

11885.02

0.0

0.0

0.0

0.0

0.0

-0.8

0.8

0.45

12500

12589.25

0.0

0.0

0.0

-0.2

0.2

-0.8

0.8

0.45

13200

13335.21

0.0

0.0

0.0

-0.3

0.3

-0.9

0.9

0.45

14000

14125.38

0.0

0.0

0.0

-0.5

0.5

-0.9

0.9

0.45

336

Appendix

NominalFrequency

ActualFrequency

0° Free-field
Frequency
Response

0° Free-field
Correction

Housing Reflection
and Microphone
Diffraction
Correction

Impact of
50 mm
Wind
Screen0° Free-field
Correction with
50 mm
Wind Screen

Impact of
90 mm
Wind
Screen0° Free-field
Correction with
90 mm
Wind Screen

Measurement
Uncertainty

15000

14962.36

0.0

0.0

0.0

-0.6

0.6

-1.1

1.1

0.45

16000

15848.93

0.0

0.0

0.0

-0.6

0.6

-1.1

1.1

0.45

17000

16788.04

0.0

0.0

0.0

-0.6

0.6

-1.2

1.2

0.45

18000

17782.79

0.0

0.0

0.0

-0.6

0.6

-1.5

1.5

0.45

19000

18836.49

0.0

0.0

0.0

-0.7

0.7

-1.7

1.7

0.45

20000

19952.62

0.0

0.0

0.0

-0.9

0.9

-1.5

1.5

0.45

337

Appendix

Frequency Weighting
NominalFrequencyHz338

Frequency Weighting
dB
A

C

Z

10

–70.4

–14.3

0.0

12.5
16
20

–63.4
–56.7
–50.5

–11.2
–8.5
–6.2

0.0
0.0
0.0

25
31.5
40

–44.7
–39.4
–34.6

–4.4
–3.0
–2.0

0.0
0.0
0.0

50
63
80

–30.2
–26.2
–22.5

–1.3
–0.8
–0.5

0.0
0.0
0.0

100
125
160

–19.1
–16.1
–13.4

–0.3
–0.2
–0.1

0.0
0.0
0.0

200
250
315

–10.9
–8.6
–6.6

0.0
0.0
0.0

0.0
0.0
0.0

400
500
630

–4.8
–3.2
–1.9

0.0
0.0
0.0

0.0
0.0
0.0

800
1000
1250

–0.8
0
+0.6

0.0
0
0.0

0.0
0
0.0

1600
2000
2500

+1.0
+1.2
+1.3

–0.1
–0.2
–0.3

0.0
0.0
0.0

NominalFrequency
Hz

Frequency Weighting
dB
A

C

Z

3150
4000
5000

+1.2
+1.0
+0.5

–0.5
–0.8
–1.3

0.0
0.0
0.0

6300
8000
10000

–0.1
–1.1
–2.5

–2.0
–3.0
–4.4

0.0
0.0
0.0

12500
16000
20000

–4.3
–6.6
–9.3

–6.2
–8.5
–11.2

0.0
0.0
0.0

Appendix

Directional Response (dB)
Based on the sound-incidence angle. (Refer IEC61672-1 paragraphs 5.3.1, 5.3.2 and 9.2.2b).
The impact on the directional response of the Windscreen 50 mm, Windscreen 90 mm and the Weather Protection WP30 is calculated by adding the frequency response correction at 0° to the below table.
Nominal Frequency
[Hz]
250
315
400
500
630
800
1000
1060
1120
1180
1250
1320
1400
1500
1600
1700
1800
1900
2000
2120
2240
2360
2500
2650
2800

ActualFrequency [Hz]

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

251.19316.23398.11
501.19630.96794.331000.00
1059.251122.021188.50
1258.931333.521412.541496.24
1584.89
1678.80
1778.28
1883.65
1995.26
2113.49
2238.722371.372511.89
2660.732818.38

-0.00
-0.00
0.00
-0.00
-0.00
-0.00
-0.00
-0.00
-0.00
0.00
0.00
-0.00
0.00
-0.00
-0.00
-0.00
-0.00
-0.00
-0.00
-0.00
0.00
-0.00
-0.00
0.00
0.00

0.00
0.01
0.01
-0.02
-0.09
-0.00
0.03
0.03
0.02
0.01
-0.01
-0.02
-0.01
0.02
0.03
0.02
0.02
0.00
0.01
0.02
0.02
0.02
0.01
0.00
0.01

0.00
0.01
0.01
-0.02
-0.11
-0.01
0.00
0.01
0.01
0.01
-0.02
-0.05
-0.04
0.00
0.02
0.01
0.00
-0.02
-0.02
-0.01
-0.01
0.00
-0.00
-0.01
-0.01

-0.00
-0.00
-0.00
-0.01
-0.06
-0.02
-0.02
-0.02
-0.02
-0.03
-0.06
-0.09
-0.07
-0.01
0.00
0.00
0.01
-0.01
-0.03
-0.05
-0.06
-0.03
-0.03
-0.05
-0.03

0.00
0.02
0.02
-0.00
-0.04
0.00
0.03
0.02
0.00
-0.02
-0.05
-0.07
-0.04
0.00
0.02
0.04
0.04
0.01
-0.03
-0.05
-0.08
-0.03
-0.03
-0.02
-0.03

-0.00
-0.01
-0.02
-0.02
0.00
-0.00
-0.02
-0.03
-0.04
-0.05
-0.09
-0.12
-0.09
-0.03
-0.00
0.01
0.02
0.01
-0.05
-0.10
-0.16
-0.10
-0.08
-0.03
-0.09

0.00
0.01
-0.01
-0.02
0.01
0.02
0.00
-0.01
-0.02
-0.04
-0.07
-0.10
-0.07
-0.02
0.01
0.05
0.04
0.04
-0.05
-0.13
-0.21
-0.13
-0.08
-0.01
-0.10

0.00
0.01
0.00
-0.01
-0.05
0.00
-0.01
-0.03
-0.05
-0.08
-0.14
-0.18
-0.13
-0.06
-0.01
0.04
0.04
0.03
-0.08
-0.18
-0.25
-0.22
-0.11
-0.01
-0.08

0.00
0.01
0.00
-0.03
-0.05
0.00
0.00
-0.03
-0.06
-0.09
-0.14
-0.17
-0.12
-0.06
-0.02
0.05
0.06
0.05
-0.04
-0.22
-0.31
-0.30
-0.16
-0.06
-0.07

0.00
0.01
0.00
-0.04
-0.06
0.00
-0.01
-0.03
-0.06
-0.08
-0.15
-0.21
-0.18
-0.11
-0.06
0.03
0.07
0.05
0.00
-0.18
-0.36
-0.39
-0.29
-0.09
-0.09

0.00
-0.01
-0.01
-0.04
-0.11
-0.03
-0.01
-0.04
-0.06
-0.10
-0.16
-0.23
-0.21
-0.14
-0.09
0.00
0.09
0.09
-0.02
-0.19
-0.44
-0.46
-0.44
-0.21
-0.16

0.00
0.01
0.01
-0.04
-0.11
0.00
0.03
0.00
-0.05
-0.10
-0.17
-0.24
-0.24
-0.18
-0.12
-0.03
0.06
0.13
0.06
-0.10
-0.37
-0.51
-0.48
-0.34
-0.18

0.00
-0.01
-0.02
-0.05
-0.13
-0.01
0.00
-0.02
-0.06
-0.12
-0.21
-0.29
-0.29
-0.23
-0.17
-0.07
0.00
0.08
0.04
-0.14
-0.34
-0.56
-0.58
-0.49
-0.36

0.00
0.00
-0.01
-0.05
-0.08
0.01
-0.01
-0.02
-0.05
-0.11
-0.20
-0.27
-0.27
-0.26
-0.23
-0.12
-0.05
0.02
0.07
-0.06
-0.32
-0.47
-0.64
-0.55
-0.51

0.00
0.01
0.00
-0.02
-0.07
0.02
0.04
0.02
-0.01
-0.07
-0.16
-0.26
-0.29
-0.27
-0.26
-0.17
-0.06
0.00
0.01
-0.01
-0.26
-0.42
-0.52
-0.62
-0.58

0.00
-0.01
-0.02
-0.04
-0.10
-0.01
0.01
-0.01
-0.03
-0.07
-0.16
-0.26
-0.28
-0.27
-0.28
-0.26
-0.18
-0.08
-0.08
-0.17
-0.26
-0.40
-0.50
-0.54
-0.70

0.00
0.00
0.00
-0.04
-0.11
-0.03
0.02
0.00
-0.02
-0.06
-0.13
-0.24
-0.31
-0.32
-0.30
-0.25
-0.22
-0.17
-0.12
-0.19
-0.33
-0.33
-0.45
-0.48
-0.57

0.00
0.01
0.00
-0.04
-0.13
-0.04
0.03
0.02
-0.01
-0.06
-0.14
-0.22
-0.26
-0.27
-0.29
-0.26
-0.22
-0.23
-0.25
-0.27
-0.39
-0.47
-0.41
-0.42
-0.55

Angle in Degrees

339

Appendix

Nominal Frequency
[Hz]
3000
3150
3350
3550
3750
4000
4250
4500
4750
5000
5300
5600
6000
6300
6700
7100
7500
8000
8500
9000
9500
10000
10600
11200
11800
12500
13200
14000
15000
16000
17000
18000
19000
20000
340

ActualFrequency [Hz]

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

2985.38
3162.28
3349.653548.133758.373981.074216.97
4466.844731.515011.875308.845623.415956.626309.57
6683.447079.467498.94
7943.28
8413.95
8912.51
9440.61
10000.00
10592.50
11220.20
11885.00
12589.30
13335.20
14125.40
14962.40
15848.90
16788.00
17782.80
18836.50
19952.60

-0.00
-0.00
-0.00
-0.00
-0.00
-0.00
-0.00
-0.00
-0.00
-0.00
0.00
-0.00
-0.00
0.00
-0.00
-0.00
-0.00
-0.00
0.00
0.00
-0.00
-0.00
-0.00
0.00
-0.00
-0.00
0.00
-0.00
-0.00
0.00
0.00
0.00
-0.00
-0.00

0.00
0.01
0.01
0.02
0.01
0.01
-0.00
0.02
0.01
0.00
0.02
0.02
0.00
0.00
0.01
0.00
0.00
0.00
-0.01
-0.00
-0.01
0.01
-0.02
-0.02
0.02
-0.03
-0.02
0.00
-0.01
-0.03
0.00
-0.05
-0.03
-0.04

-0.03
-0.00
0.01
0.02
-0.01
-0.02
-0.02
-0.01
-0.02
-0.05
-0.01
-0.01
-0.03
-0.05
-0.03
-0.05
-0.09
-0.03
-0.08
-0.08
-0.12
-0.01
-0.18
-0.08
0.01
-0.23
-0.13
-0.08
-0.11
-0.13
-0.14
-0.25
-0.25
-0.25

-0.09
-0.06
0.00
0.01
-0.07
-0.10
-0.07
-0.03
-0.08
-0.14
-0.07
-0.04
-0.12
-0.13
-0.09
-0.12
-0.21
-0.09
-0.18
-0.20
-0.23
-0.08
-0.44
-0.13
-0.05
-0.54
-0.24
-0.20
-0.29
-0.37
-0.36
-0.48
-0.54
-0.55

-0.12
-0.06
-0.01
0.00
-0.08
-0.16
-0.09
-0.02
-0.10
-0.20
-0.10
-0.04
-0.17
-0.20
-0.14
-0.15
-0.33
-0.15
-0.25
-0.32
-0.26
-0.16
-0.68
-0.05
-0.28
-0.87
-0.27
-0.42
-0.54
-0.71
-0.63
-0.71
-0.75
-0.85

-0.19
-0.13
-0.06
-0.03
-0.12
-0.24
-0.18
-0.06
-0.17
-0.35
-0.26
-0.10
-0.24
-0.36
-0.30
-0.22
-0.58
-0.30
-0.37
-0.61
-0.41
-0.49
-0.93
-0.15
-0.82
-1.05
-0.44
-0.85
-0.92
-1.08
-0.97
-1.06
-1.13
-1.28

-0.20
-0.18
-0.09
0.01
-0.09
-0.30
-0.25
-0.07
-0.14
-0.44
-0.39
-0.15
-0.27
-0.45
-0.46
-0.25
-0.71
-0.50
-0.44
-0.82
-0.46
-0.80
-0.95
-0.48
-1.17
-0.98
-0.77
-1.20
-1.15
-1.25
-1.30
-1.54
-1.71
-1.80

-0.25
-0.30
-0.15
0.00
-0.09
-0.36
-0.40
-0.18
-0.18
-0.54
-0.58
-0.29
-0.32
-0.52
-0.67
-0.37
-0.82
-0.77
-0.54
-1.10
-0.68
-1.13
-1.09
-1.00
-1.21
-1.31
-1.35
-1.47
-1.59
-1.79
-1.94
-2.14
-2.25
-2.42

-0.31
-0.36
-0.23
-0.07
-0.10
-0.39
-0.50
-0.27
-0.19
-0.53
-0.71
-0.45
-0.38
-0.59
-0.84
-0.56
-0.84
-1.08
-0.71
-1.22
-0.98
-1.32
-1.43
-1.21
-1.45
-1.90
-1.48
-1.81
-2.04
-2.16
-2.24
-2.40
-2.67
-2.97

-0.31
-0.42
-0.37
-0.18
-0.11
-0.35
-0.54
-0.42
-0.32
-0.60
-0.85
-0.71
-0.57
-0.67
-0.88
-0.90
-0.96
-1.26
-1.11
-1.31
-1.38
-1.44
-1.89
-1.38
-2.04
-2.08
-1.92
-2.35
-2.32
-2.70
-2.92
-3.27
-3.51
-3.70

-0.30
-0.49
-0.46
-0.29
-0.22
-0.38
-0.60
-0.57
-0.47
-0.63
-0.87
-0.88
-0.80
-0.82
-0.94
-1.12
-1.31
-1.30
-1.52
-1.56
-1.66
-1.72
-2.22
-1.78
-2.28
-2.56
-2.49
-2.64
-3.03
-3.27
-3.39
-3.67
-4.10
-4.54

-0.34
-0.47
-0.46
-0.40
-0.35
-0.41
-0.52
-0.58
-0.66
-0.82
-0.90
-0.94
-1.03
-1.11
-1.05
-1.09
-1.66
-1.46
-1.63
-2.04
-1.71
-2.25
-2.35
-2.32
-2.65
-3.15
-2.74
-3.39
-3.42
-3.73
-4.12
-4.52
-4.84
-5.21

-0.43
-0.51
-0.55
-0.47
-0.49
-0.62
-0.64
-0.56
-0.70
-1.01
-1.07
-1.01
-1.20
-1.40
-1.41
-1.17
-1.82
-1.91
-1.75
-2.42
-2.12
-2.57
-2.88
-2.55
-3.25
-3.36
-3.46
-3.63
-4.20
-4.49
-4.75
-5.26
-5.69
-6.21

-0.52
-0.62
-0.55
-0.50
-0.62
-0.76
-0.77
-0.66
-0.71
-1.12
-1.30
-1.16
-1.26
-1.52
-1.78
-1.52
-1.81
-2.16
-2.09
-2.47
-2.67
-2.74
-3.31
-3.01
-3.53
-3.98
-3.76
-4.44
-4.53
-5.07
-5.44
-5.88
-6.48
-7.04

-0.70
-0.70
-0.67
-0.48
-0.54
-0.86
-0.93
-0.77
-0.73
-1.09
-1.40
-1.39
-1.41
-1.56
-1.85
-1.96
-2.11
-2.21
-2.41
-2.78
-2.78
-3.30
-3.50
-3.50
-4.03
-4.44
-4.40
-4.84
-5.20
-5.65
-6.07
-6.58
-7.12
-7.80

-0.79
-0.92
-0.82
-0.65
-0.60
-0.83
-1.10
-1.00
-0.94
-1.15
-1.36
-1.51
-1.71
-1.83
-1.87
-2.03
-2.57
-2.55
-2.56
-3.18
-3.08
-3.49
-4.13
-3.73
-4.56
-4.86
-4.85
-5.51
-5.80
-6.31
-6.66
-7.38
-7.94
-8.59

-0.84
-0.95
-1.05
-0.84
-0.78
-0.87
-1.01
-1.12
-1.16
-1.41
-1.43
-1.44
-1.77
-2.15
-2.17
-2.00
-2.58
-2.90
-2.89
-3.29
-3.45
-3.95
-4.36
-4.36
-5.04
-5.42
-5.54
-6.06
-6.52
-7.11
-7.59
-8.19
-8.95
-9.59

-0.73
-0.97
-1.01
-1.08
-0.98
-1.11
-1.01
-1.05
-1.18
-1.62
-1.76
-1.54
-1.69
-2.05
-2.47
-2.38
-2.68
-3.00
-3.30
-3.76
-3.66
-4.12
-4.64
-4.54
-5.54
-5.75
-5.99
-6.53
-6.78
-7.72
-8.07
-8.93
-9.48
-10.28Angle in Degrees

Appendix

Nominal Frequency
[Hz]
250
315
400
500
630
800
1000
1060
1120
1180
1250
1320
1400
1500
1600
1700
1800
1900
2000
2120
2240
2360
2500
2650
2800
3000
3150
3350
3550
3750
4000
4250
4500
4750

ActualFrequency [Hz]

90

95

100

105

110

115

120

125

130

135

140

145

150

155

160

165

170

175

180

251.19316.23398.11
501.19630.96794.331000.00
1059.251122.021188.50
1258.931333.521412.541496.24
1584.89
1678.80
1778.28
1883.65
1995.26
2113.49
2238.722371.372511.89
2660.732818.382985.38
3162.28
3349.653548.133758.373981.074216.97
4466.844731.51

0.00
0.01
0.00
-0.06
-0.13
-0.04
0.03
0.03
0.01
-0.05
-0.14
-0.20
-0.21
-0.22
-0.26
-0.27
-0.23
-0.19
-0.25
-0.42
-0.48
-0.51
-0.55
-0.43
-0.46
-0.71
-0.84
-1.00
-0.97
-1.25
-1.33
-1.42
-1.09
-1.19

0.00
0.01
-0.01
-0.05
-0.06
-0.04
-0.02
0.00
0.01
-0.02
-0.11
-0.21
-0.24
-0.22
-0.23
-0.22
-0.22
-0.22
-0.23
-0.38
-0.63
-0.65
-0.58
-0.55
-0.55
-0.70
-0.85
-0.80
-0.92
-1.10
-1.47
-1.71
-1.47
-1.42

0.00
-0.01
-0.03
-0.09
-0.17
-0.08
-0.06
-0.06
-0.06
-0.07
-0.14
-0.23
-0.27
-0.25
-0.23
-0.18
-0.16
-0.20
-0.29
-0.40
-0.54
-0.73
-0.77
-0.65
-0.65
-0.83
-0.88
-0.90
-0.78
-0.88
-1.39
-1.57
-1.81
-1.77

0.00
0.00
-0.02
-0.08
-0.10
-0.08
-0.09
-0.09
-0.09
-0.11
-0.15
-0.20
-0.23
-0.23
-0.23
-0.20
-0.15
-0.12
-0.17
-0.37
-0.60
-0.67
-0.73
-0.76
-0.75
-0.90
-1.10
-1.05
-0.80
-0.94
-1.06
-1.34
-1.62
-1.77

0.00
0.01
0.00
-0.04
-0.08
-0.09
-0.06
-0.07
-0.10
-0.13
-0.19
-0.23
-0.23
-0.22
-0.23
-0.19
-0.16
-0.12
-0.12
-0.23
-0.48
-0.68
-0.74
-0.67
-0.71
-0.97
-1.15
-1.16
-1.12
-0.98
-1.10
-1.34
-1.20
-1.45

0.00
-0.01
-0.04
-0.09
-0.17
-0.09
-0.09
-0.10
-0.12
-0.15
-0.23
-0.31
-0.31
-0.27
-0.24
-0.19
-0.15
-0.15
-0.23
-0.33
-0.45
-0.53
-0.64
-0.65
-0.72
-0.88
-1.10
-1.29
-1.20
-1.24
-1.49
-1.48
-1.25
-1.43

0.00
0.00
-0.01
-0.05
-0.14
-0.07
-0.06
-0.08
-0.10
-0.13
-0.20
-0.28
-0.29
-0.28
-0.27
-0.21
-0.15
-0.10
-0.13
-0.26
-0.47
-0.55
-0.57
-0.53
-0.55
-0.75
-1.01
-1.03
-1.09
-1.31
-1.52
-1.61
-1.63
-1.66

0.00
0.00
-0.02
-0.07
-0.12
-0.09
-0.10
-0.12
-0.14
-0.17
-0.23
-0.31
-0.33
-0.33
-0.32
-0.27
-0.23
-0.19
-0.18
-0.25
-0.43
-0.56
-0.63
-0.59
-0.61
-0.72
-0.79
-0.91
-0.99
-1.10
-1.35
-1.69
-1.82
-1.76

0.00
0.01
0.00
-0.03
-0.08
-0.05
-0.09
-0.10
-0.12
-0.15
-0.21
-0.28
-0.30
-0.30
-0.29
-0.25
-0.21
-0.18
-0.24
-0.39
-0.53
-0.56
-0.59
-0.55
-0.59
-0.76
-0.88
-0.87
-0.78
-0.86
-1.19
-1.47
-1.47
-1.56

0.00
0.00
-0.01
-0.05
-0.09
-0.05
-0.10
-0.12
-0.14
-0.17
-0.24
-0.32
-0.36
-0.35
-0.34
-0.31
-0.26
-0.21
-0.21
-0.35
-0.55
-0.67
-0.72
-0.72
-0.72
-0.81
-0.85
-0.87
-0.84
-0.93
-1.14
-1.25
-1.20
-1.43

0.00
0.01
0.01
-0.03
-0.05
-0.03
-0.07
-0.09
-0.11
-0.15
-0.23
-0.30
-0.32
-0.32
-0.31
-0.28
-0.26
-0.24
-0.29
-0.38
-0.55
-0.64
-0.69
-0.66
-0.72
-0.96
-1.12
-1.07
-0.91
-0.92
-1.11
-1.29
-1.31
-1.41

0.00
0.02
0.03
0.00
-0.08
-0.04
-0.04
-0.06
-0.08
-0.11
-0.20
-0.28
-0.29
-0.27
-0.24
-0.22
-0.21
-0.19
-0.24
-0.36
-0.59
-0.67
-0.72
-0.71
-0.76
-0.92
-1.02
-1.04
-0.99
-1.11
-1.38
-1.49
-1.39
-1.30

0.00
0.00
0.00
-0.03
-0.10
-0.07
-0.04
-0.07
-0.09
-0.12
-0.21
-0.29
-0.28
-0.28
-0.26
-0.21
-0.17
-0.11
-0.18
-0.29
-0.48
-0.60
-0.65
-0.65
-0.74
-1.00
-1.20
-1.20
-1.10
-1.13
-1.33
-1.45
-1.45
-1.62

0.00
-0.02
-0.01
-0.04
-0.11
-0.06
-0.06
-0.10
-0.11
-0.13
-0.22
-0.29
-0.27
-0.29
-0.27
-0.22
-0.21
-0.12
-0.19
-0.26
-0.50
-0.55
-0.59
-0.60
-0.60
-0.83
-1.06
-1.11
-1.07
-1.16
-1.43
-1.60
-1.60
-1.66

0.00
0.00
0.02
0.00
-0.09
-0.05
-0.01
-0.05
-0.06
-0.07
-0.19
-0.29
-0.26
-0.28
-0.25
-0.18
-0.21
-0.09
-0.20
-0.25
-0.52
-0.52
-0.58
-0.56
-0.53
-0.76
-0.95
-0.95
-0.81
-0.87
-1.12
-1.29
-1.35
-1.50

0.00
0.00
0.02
-0.01
-0.12
-0.03
0.00
-0.06
-0.06
-0.06
-0.18
-0.27
-0.21
-0.23
-0.21
-0.11
-0.18
-0.04
-0.18
-0.18
-0.49
-0.50
-0.59
-0.56
-0.54
-0.82
-1.02
-0.99
-0.84
-0.85
-1.03
-1.18
-1.14
-1.19

0.00
-0.01
0.01
-0.01
-0.13
-0.03
0.02
-0.04
-0.04
-0.03
-0.13
-0.22
-0.15
-0.18
-0.18
-0.06
-0.11
0.05
-0.09
-0.11
-0.42
-0.39
-0.50
-0.45
-0.43
-0.75
-0.93
-0.91
-0.81
-0.86
-1.09
-1.23
-1.19
-1.23

0.00
-0.03
0.00
-0.01
-0.09
0.00
0.04
-0.02
-0.03
-0.02
-0.13
-0.22
-0.13
-0.15
-0.16
-0.03
-0.07
0.07
-0.04
-0.04
-0.29
-0.29
-0.41
-0.29
-0.31
-0.60
-0.75
-0.71
-0.62
-0.68
-0.93
-1.07
-1.00
-1.03

0.00
-0.03
-0.01
-0.04
-0.22
-0.06
0.00
-0.08
-0.06
-0.01
-0.11
-0.22
-0.16
-0.19
-0.19
-0.06
-0.09
0.10
0.01
-0.06
-0.33
-0.31
-0.42
-0.27
-0.32
-0.60
-0.69
-0.65
-0.57
-0.66
-0.90
-1.02
-0.94
-0.92

Angle in Degrees

341

Appendix

Nominal Frequency
[Hz]
5000
5300
5600
6000
6300
6700
7100
7500
8000
8500
9000
9500
10000
10600
11200
11800
12500
13200
14000
15000
16000
17000
18000
19000
20000

ActualFrequency [Hz]Angle in Degrees
90

95

100

105

110

115

120

125

130

135

140

145

155

160

165

170

175

180

5011.87-1.54 -1.54 -1.97 -2.36 -2.08 -1.67 -1.68 -2.07 -2.18 -1.95 -1.68 -1.64 -2.04 -2.00 -1.93 -1.63 -1.64 -1.37 -1.24
5308.84 -1.97 -1.84 -1.95 -2.45 -2.54 -2.13 -1.97 -2.36 -2.54 -2.17 -1.83 -1.93 -2.27 -2.18 -2.22 -1.86 -1.93 -1.71 -1.57
5623.41 -1.90 -1.97 -1.84 -2.19 -2.63 -2.35 -1.91 -2.14 -2.42 -2.20 -1.96 -2.06 -2.26 -2.20 -2.25 -1.83 -1.86 -1.63 -1.50
5956.62 -1.98 -2.40 -2.27 -2.24 -2.80 -2.94 -2.34 -2.24 -2.58 -2.60 -2.33 -2.27 -2.25 -2.50 -2.48 -2.11 -2.03 -1.76 -1.57
6309.57 -1.97 -2.41 -2.66 -2.33 -2.52 -3.10 -2.82 -2.54 -2.81 -2.94 -2.57 -2.33 -2.46 -2.86 -2.80 -2.41 -2.36 -2.16 -1.95
6683.44 -2.28 -2.33 -2.93 -3.03 -2.93 -3.43 -3.27 -2.75 -2.94 -3.25 -2.84 -2.45 -2.69 -3.26 -3.09 -2.84 -2.68 -2.44 -2.21
7079.46 -2.70 -2.53 -2.80 -3.16 -2.90 -3.24 -3.69 -3.21 -3.11 -3.53 -3.16 -2.69 -2.90 -3.27 -3.15 -2.90 -2.66 -2.49 -2.22
7498.94 -3.25 -3.15 -3.03 -3.66 -3.59 -3.61 -4.21 -3.73 -3.25 -3.83 -3.91 -3.34 -3.41 -3.62 -3.67 -3.40 -3.14 -3.03 -2.78
7943.28 -3.29 -3.52 -3.42 -3.57 -4.16 -3.83 -4.18 -4.54 -3.75 -3.90 -4.18 -3.68 -3.61 -3.79 -4.03 -3.74 -3.41 -3.38 -3.11
8413.95 -3.34 -3.64 -3.82 -3.66 -4.19 -4.16 -4.40 -4.77 -4.11 -4.11 -4.63 -4.00 -3.65 -3.89 -4.28 -4.03 -3.57 -3.59 -3.25
8912.51 -4.04 -4.17 -4.41 -4.47 -4.43 -5.18 -4.56 -5.53 -5.13 -4.45 -5.00 -4.78 -4.29 -4.50 -4.97 -4.73 -4.11 -4.21 -3.86
9440.61 -4.08 -4.32 -4.57 -4.55 -4.70 -5.00 -5.17 -5.01 -5.59 -4.88 -5.00 -4.98 -4.43 -4.61 -5.29 -5.01 -4.21 -4.25 -3.94
10000.00 -4.41 -4.95 -5.13 -5.26 -5.09 -5.64 -5.74 -5.67 -6.17 -5.59 -5.62 -5.57 -4.81 -5.16 -5.96 -5.78 -4.92 -4.99 -4.66
10592.50 -4.84 -5.66 -5.73 -5.89 -5.99 -5.85 -6.61 -6.17 -6.86 -6.35 -6.05 -6.69 -5.69 -5.79 -6.38 -6.32 -5.56 -5.62 -5.33
11220.20 -5.08 -5.29 -5.96 -5.82 -6.22 -5.98 -6.40 -6.63 -6.54 -6.77 -6.08 -6.38 -6.07 -5.74 -6.19 -6.46 -5.65 -5.71 -5.42
11885.00 -5.81 -6.22 -6.60 -6.69 -6.84 -7.06 -7.08 -7.77 -7.39 -7.95 -6.88 -7.35 -6.86 -6.32 -6.89 -7.28 -6.63 -6.49 -6.22
12589.30 -6.24 -6.68 -7.02 -7.57 -7.29 -7.66 -7.45 -8.08 -7.93 -8.49 -8.13 -7.96 -7.81 -6.96 -7.43 -8.07 -7.42 -7.11 -6.92
13335.20 -6.47 -6.80 -7.26 -7.56 -7.63 -8.13 -8.10 -8.29 -8.45 -8.48 -8.34 -7.99 -8.30 -7.15 -7.48 -8.50 -7.89 -7.43 -7.36
14125.40 -7.09 -7.62 -7.91 -8.27 -8.65 -8.89 -9.22 -8.90 -9.58 -9.60 -9.77 -8.84 -9.40 -7.94 -8.18 -9.45 -8.78 -8.17 -8.20
14962.40 -7.77 -8.15 -8.31 -8.80 -9.13 -9.52 -9.70 -9.36 -9.89 -9.60 -9.91 -8.94 -9.53 -8.95 -8.85 -10.27 -9.43 -8.58 -8.69
15848.90 -8.14 -8.57 -9.46 -9.82 -9.82 -10.40 -10.67 -10.30 -10.88 -11.05 -11.53 -10.63 -10.30 -9.99 -9.98 -11.23 -10.39 -9.57 -9.70
16788.00 -9.03 -9.53 -9.85 -10.29 -10.41 -11.12 -11.48 -11.22 -11.33 -11.86 -11.73 -11.51 -11.22 -10.86 -10.22 -11.69 -11.46 -10.42 -10.51
17782.80 -9.76 -10.24 -10.80 -10.99 -11.37 -11.93 -12.53 -12.49 -12.07 -12.86 -12.64 -12.84 -11.76 -11.89 -10.91 -12.08 -12.48 -11.15 -11.39
18836.50 -10.50 -11.05 -11.74 -12.45 -12.44 -12.86 -13.22 -13.33 -12.90 -13.90 -13.76 -13.71 -13.09 -13.30 -12.01 -12.61 -13.63 -12.05 -12.01
19952.60 -11.34 -11.75 -12.63 -13.00 -13.60 -13.92 -14.22 -14.21 -14.52 -14.27 -15.01 -14.99 -13.71 -14.36 -12.72 -13.38 -15.20 -13.07 -12.92

The maximum measurement uncertainty of the data is with 95 % probability (k=2).
• 250 Hz to 1 kHz
0.3 dB• 1 kHz to 4 kHz		
0.5 dB• 4 kHz to 8 kHz		
1.0 dB• 8 kHz to 12.5 kHz
1.5 dB
342

150

Appendix

343

Appendix

Information for Calibration
Type Description• Integrating sound level meter type NTi Audio XL2-TA
Standards
The XL2-TA Sound Level Meter has been certified in accordance with the class 1 requirements of• ISO 61672-1 (2014 und 2003)• ISO 61672-2 (2014 und 2003)• ISO 61260 (2014 und 2003)• DIN 45657 (2014)• Welmec 7.2 «Software Guide» (2011)

Approval Identification
The XL2-TA Sound Level Meter requires the approved firmware as follows:• Germany: V4.71• France: V4.21• Austria: V4.21• Switzerland: V4.11

344

Hints for Performing the Electrical Measurements
Electrical input facility(Refer IEC61672-1 paragraphs 5.1.15, 9.3.g)
The capsule replacement NTI-K65-15 is used to insert electrical signals to the preamplifier MA220. The device provides at
one side a contact that corresponds to the center contact of
the replaced microphone capsule, at the other side a BNCplug for the electrical signals. The impedance at the outputof the device is 15 pF with a maximum deviation of ±1 pF.
The electrical noise floor is measured by shorting the contacts of the BNC plug. Before the NTI-K65-15 can be mounted to the preamplifier MA220, the microphone capsule mustfirst be detached. The nominal sensitivity S of the capsule isS = 42 mV/Pa. Measurements with the NTI-K65-15 therefore
require that the sensitivity in the calibration menu is manually
adjusted to S = 42 mV/Pa. The linear operating ranges according to IEC 61672 have been verified during the type approval
procedure.
Certified Calibrator
The following sound level calibrators are certified with the
XL2-TA with a 114 dB, 1 kHz reference signal.
• Larson Davis CAL200• B&K 4231
• Norsonic Nor-1251, Nor-1256• Microtech Gefell 4010

Appendix

Compulsory Calibrated Applications
The following acoustic measurements have been verified byGerman PTB during the type approval process:Instantaneous sound pressure levels:• LAF
A-weighted sound pressure level with time weighting FAST
• LAS
A-weighted sound pressure level with time weighting SLOW• LCF
C-weighted sound pressure level with time weighting FAST
• LCS
C-weighted sound pressure level with time weighting SLOW
• LZF
unweighted sound pressure level with time weighting FAST
• LZS
unweighted sound pressure level with time weighting SLOWTime averaged sound pressure levels:• LCpeak
Peak value of the C-weighted sound level• LAeqA-weighted average level• LAE
A-weighted sound exposure level• LAFT3eq
A-weighted clock-impulse maximum level with time weighting FAST for a clock-impulse duration of 3 seconds• LAFT5eq
A-weighted clock-impulse maximum level with time weighting FAST for a clock-impulse duration of 5 seconds• LAI
A-weighted sound pressure level with time weighting
IMPULSE345