OPERATING MANUAL

Minirator MR2 / MR-PRO

Contact NTi Audio at
Headquarter
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info@nti-audio.com
americas@nti-audio.com
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www.nti-audio.com
NTi Audio AG
Im alten Riet 102, 9494 Schaan
Liechtenstein, Europe
is an ISO 9001:2015 certified company.
©

All rights reserved.
All information subject to change without noticeFirmware MR2 2.16, MR-PRO 2.16
Version Jul 2021®
™

Minirator and Minilyzer are registered trademarks of NTi Audio.
XL2, Exel, Acoustilyzer, MiniSPL and MiniLINK are trademarks of NTi Audio.

Made in
Sw i t ze r l a n d

Table of Contents

Table of Contents
1. Basics ...............................................................................4
Introduction.....................................................................4
Scope of Delivery...........................................................4
Notes..............................................................................5
Accessories....................................................................6
2. Overview..........................................................................7
Connections....................................................................7
Buttons and Operating Elements....................................8
Screen Display................................................................9Power Supply................................................................ 11
Characteristics of the Outputs...................................... 12
3. Getting Started.............................................................14
Inserting the Batteries.................................................. 14
Fitting the Protective Shock Jacket (MR-PRO only)...... 15
Attaching the Hand Strap.............................................. 16
Connecting the Minirator ............................................. 17
4. Operation....................................................................... 18
Switching the Minirator on and off................................ 18
Navigation in the Menu Bar.......................................... 18
Selecting a Test Signal.................................................. 19
Setting the Parameters.................................................20
Setting the Sensitivity of the Rotary Wheel..................21
System Settings............................................................22
Configurations (MR-PRO only)......................................24
5. Test Signals.....................................................................26
Sine...............................................................................26
Sweep...........................................................................26

Chirp.............................................................................28
Delay Test......................................................................29
Pink Noise.....................................................................30
White Noise..................................................................31
Polarity..........................................................................31
Wave File Player (MR-PRO only)...................................32
6. Measurement Functions...............................................35
Impedance Test in Generator Mode..............................35
Balance Display.............................................................36
Measuring Phantom Power Voltages............................37
XLR Cable Test..............................................................38
Impedance Test.............................................................40
7. Taking a Screenshot.......................................................42
8. Updating the Firmware ................................................43
9. Tips and Troubleshooting..............................................44
Resetting to the Factory Settings.................................44
Reloading WAV-files (MR-PRO only).............................44
Behavior with low-impedance Loads............................44
PC recognizes Minirator as GPS Camera......................44
Faults and their Correction............................................45
10. Further Information.....................................................46
My NTi Audio................................................................46
Warranty Conditions.....................................................47
Calibration Certificate....................................................47
Service and Repairs......................................................47
Declaration of Conformity.............................................48
11. Technical Data Minirator..............................................49
3

Basics

1. Basics
Introduction

Scope of Delivery

Thank you for purchasing the Minirator. The Minirator is a powerful audio generator, offering a wide range of analog test signals for the calibration, maintenance and repair of professional
audio systems.

The following items are included with the respective model:

MR2:

• MR2
• Operating manual• USB cable• Hand strap

MR-PRO:• MR-PRO• Protective shock jacket• Operating manual• USB cable• Hand strap

The rotary wheel combined with surrounding fast access function keys enables instant and intuitive operation without compromising fine adjustment capabilities.
While the MR2 has been optimized for “Value at a most attractive price“, the MR-PRO has been developed with additional innovative functionality for even more demanding applications.
The MR-PRO is also equipped with the following functions:• Integrated measurement functions for impedance, balanceand phantom power voltages• Playback of WAV-files• Cable tester• Impedance test of distributed 70V/100V speaker systems

4

Basics

Notes

Danger of electric shock
Never connect the instrument to a power
output!
Non-compliance could result in damage topersons or property that is not covered by
the warranty.

Damage caused by opening the instrument
Never open the instrument.
The instrument can be damaged if the housing is opened, and your warranty will be invalid.

Damage through damp
Do not use the instrument in damp environments!
The instrument can be permanently damaged by the penetration of water.

5

Basics

Accessories
Accessories available for the MR2 / MR-PRO:• Pouch MR2 / MR-PRO

NTi Audio # 600 000 302

The soft pouch protects the Minirator against shock anddust and comes with a convenient belt-clip.

• Exel System Case

NTi Audio # 600 000 334

This compact system case provides the professional transport protection for work in the field. It offers space for thehandheld instruments, cables and connectors.

• Mains Power Adapter

NTi Audio # 600 000 333

Mains Power Adapter with removable plug types. The Mains
Power Adapter suits the typical power sockets in Australia,
China, Europe, Japan, US and UK.

6• Minirator -40dB Adapter

NTi Audio # 600 000 312

Attenuator for high quality microphone level signals.
• Cable Test Adapter

NTi Audio # 600 000 311

The Cable Test Adapter is used for single-ended cable testing. By installing the Cable Test Adapter at the far end of thecable, the MR-PRO will be able to complete its cable test
procedure and display the condition.
• 70V/100V Protection MR-PRO

NTi Audio # 600 000 313

Protects Minirator MR-PRO against accidentally applied
70V/100V voltages during impedance or power testing at
distributed speaker systems.
• Calibration Certificate

NTi Audio # 600 000 018

Individual calibration certificate with serial number, traceable according to the ISO/IEC 17025 standard. Calibration
certificates for new products have to be ordered together
with the product. After the purchase we recommend theannual calibration of the instrument.

Overview

2. Overview
Connections
The Minirator has the following connections:

1

1
2
3

2

RCA output (unbalanced)
XLR output (balanced)
DC power socket

3

4

4
5

5

XLR input for the cable test
(MR-PRO only)
USB connection (Mini-B, 5 pin)7

Overview

Buttons and Operating Elements
1

2

4

3

esc

9

wave

level

freq

sens

8

4

Wave

Selection of the test signal.

5

Freq

Setting the output frequency. Direct jump to
the “PARAM” menu with the “SWEEP” and“CHIRP” test signals.

6

Mute

Switches off the output signal.
Mute is indicated at the lower right corner ofthe display and a flashing mute button.

5

The button lights up continually during thepauses of the “PNoise” and “Chirp” signal
waveforms.

mute

7

7

On/OffSwitches the instrument off if held down for
one second. Switches the back-lighting on
and off.

6

1

ESC

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

8

Sens

Changes the sensitivity steps of the frequency and level settings.

2

Rotarywheel

Slow turning: Precise setting of the value.
Rapid turning: Setting the value in larger
steps.

9

Level

3

Enter

Confirming a selection.

Setting the output level. You can set up theoutput signal in the following units:dBV, dBu,V. With the MR-PRO, dBF (dB referred to Full Scale) and % units are available
when playing back Wave files.

8Overview

Screen Display
Main Menu

Settings for Signal Generation
1

2

1

2

3

4

7

4

2

3
4

5

3

1
1

6

Menu bar
Battery symbol:
If the battery symbol lights up the batteries are almost
completely discharged and must be replaced.
Display of the readings (MR-PRO)Settings for signal generation

2
3
4
5
6
7

Test signal
Start / Stop for certain test signals
Setting up the parameters
Single / continuous mode for certain test signals
Output frequency
Units for the output level
Output level
9Overview

Display of the Measured Values (MR-PRO)Taking a Screenshot
A screenshot may be stored in the Minirator MR-PRO memoryfor documentation of the generator settings or the measurement results. Follow these steps:

1

1
2
3

Phantom voltage
Balance
Impedance

2

3

•
•
•
•
•
•

Connect the Minirator MR-PRO to the computer.
Create a new folder “Screen” in the MR-PRO memory.
Remove the instrument from the computer.
Power on the Minirator MR-PRO.
Adjust the required settings or perform a measurement.
Press the On/Off button and the Enter-button at the sametime shorty.

 The screenshot has been stored in the MR-PRO memory.

10

Overview

Power Supply
Battery Operation
In order to be always able to use the Minirator flexibly, we recommend the use of batteries.

We recommend using the NTi Audiomains power adapter. This is a switching power supply and leads to increased
noise at the unbalanced output connector.

• Only use 3x AA, LR6 batteries.
• The battery consumption increases athigher level setting as well is based on
the connected load.
• During operation, the battery temperature may increase noticeably. This is nota defect.
• The instrument can also be used with rechargeable batteries.

Alternatively you may utilize a linear power
supply adapter with EU-connector for unbalanced signal applications.
NTi Audio # 600 000 305.

Operation using the mains power supply
You can also connect the Minirator to a mains socket with a
DC power supply unit, which is available for order at NTi Audio. We recommend remaining the batteries inside the instrument.

In case you want to make use of a different
DC power supply unit, you must observe
the following specifications:• electrically-isolated, non-earthed linear
DC power supply unit
• 2.1 x 5.5 x 9.5 mm plug• connection• Voltage from 5 to 9 volts and a current ofat least 500 mA.
Damage caused by using an inappropriate
external DC supply is not covered by warranty.

11

Overview

Characteristics of the Outputs
The Minirator has two outputs that are wired in parallel: An
unbalanced RCA output and a balanced, non-earthed XLR output. Both outputs are resistant to externally applied phantom
power. Wherever possible, always use balanced (XLR) connections, as these have much better immunity to interference thanunbalanced connections.

Do not use both outputs at the sametime.
The simultaneous use of both outputs could
lead to a short-circuit in one of the generator
outputs in the connected instrument.

MR2 Outputs
Both the RCA and the XLR have a balanced output impedanceof 200 Ohm.

The voltage at the MR2 XLR or RCA output
is less than the set voltage U with low impedance loads.
Example:A balanced 200 Ohm load impedance matching the 200 ohm output impedance will result in the expected output drop of 6 dB.

MR2

RCA

Allocation of the XLR Output:

2

3

1

1

2
3

12

PIN 1
PIN 2
PIN 3

~

U/2

~

U/2

U

100

2

0.5

1

100

3

XLR

Overview

MR-PRO Outputs
Both the RCA and the XLR have a balanced output impedanceof only 12.5 ohms. The level of the XLR output corresponds
closely to the set output voltage, based upon the low 12.5 ohm
output impedance of the generator.

MR-PROI<10mA

~

U/2

~

U/2

U

RCA
6.3

2

0.5

1

6.3

3

XLR

I<10mA

Behavior with low-impedance Loads
The maximum output current of the MR-PRO is 10 mA. If theconnected load consumes more current, the internal regulationof the MR-PRO reduces the output level. This condition will be
indicated on the screen by the flashing output level display:.

XLR short-circuit between Pin 1 and 3
Commercially available XLR to RCA adapters short-circuit the XLR Pins 1 and 3. Do
not use such adapters with the Minirator!
They will reduce the signal quality, thus use
the RCA output instead.

The MR-PRO is designed for loads down to
600 Ohm. Depending on the output level
and the output frequency, however, thelevel is maintained, even for lower load impedances.

Minirator -40dB Adapter
For highest quality microphone level signals
we recommend the “Minirator -40dB Attenuator” which is available as an accessory.
It improves the signal to noise ratio for low
level signals by 40 dB.
NTi Audio # 600 000 312

13Getting Started

3. Getting Started
Inserting the Batteries• Only use batteries from the same manufacturer.
• Replace the discharged batteries by newones.
• Do not mix used and new batteries.

• Open the battery cover.
• Insert three AA-LR6 batteries with the same state of charge,
paying attention to the +/- marking in the battery compartment.
• Close the battery cover once the batteries have been inserted.

 You have now successfully inserted the batteries.

14

2.

1.

Getting Started

Fitting the Protective Shock Jacket(MR-PRO only)
With the MR-PRO, you can fit the supplied protective shock
jacket. This will protect the instrument against light impacts
without impairing its easy operation.

• Push the lower end of your MR-PRO into the lower end of
the protective shock jacket.
• Push the upper end of the MR-PRO into the protective
housing.

 You have now fitted the protective shock jacket

1.

2.

Damage through impacts / shocks• The protective shock jacket shields your
MR-PRO against reasonable impacts that
could occur in normal use.
• But do not intentionally subject the instrument to extreme stress!
• Please do not drop the instrument!
• Damage caused by dropping or impact is
not covered by warranty.

15

Getting Started

Attaching the Hand Strap
To prevent you from accidentally dropping the Minirator, a handstrap is supplied with the instrument. You can also fit the handstrap when the protective shock jacket of the MR-PRO has
been fitted.

• Pull the hand strap through the opening.
• Pull the rear part of the hand strap through the loop of thefront part.
• Pull the hand strap tight.

 You have now secured the hand strap.

1.

2.
3.

16

Getting Started

Connecting the Minirator
XLR Connection• Connect the Minirator to your audio device using an XLR
cable. Note that the locking pin of the plug must be locatedon the lower side of the instrument!

 You have now connected the Minirator.

1.

2.

RCA Connection• Connect the Minirator to the input of the unit to be tested
using a RCA cable.

 You have now connected the Minirator.

1.

2.

17

Operation

4. Operation
Switching the Minirator on and off
Switching the Minirator on

Navigation in the Menu Bar
The menu bar is divided into two parts. On the left-hand side,
you can choose between the Generator, Cable test (MR-PRO
only), Impedance (MR-PRO only) and System functions.

• To switch the Minirator on, press the “On/Off” button.

 The display lighting is switched on.
You have switched on the Minirator.

Switching the Minirator off• To switch the Minirator off, press the “On/Off” button andhold it down for one second.

 You have switched off the Minirator.

• To do this, select the left side of the menu bar with the rotary
wheel and confirm with “Enter”.

 A selection window opens.
• Select the desired function with the rotary wheel.
• Confirm the selection with “Enter”.

 You have now selected the desired function.
You can save and call up configurations on the right-hand sideof the menu bar (see the “Configurations” chapter, MR-PRO
only).

18

Operation

Selecting a Test Signal
You have two choices for selecting test signals. You can use
either the direct buttons or the rotary wheel.

Signal selection using the direct buttons• Ensure that GENERATOR 1 is selected in the menu bar.
• Press the “Wave” button.

 A selection menu appears.
• Select the desired test signal with the rotary wheel.
• Press “Enter”.

Signal selection using the rotary wheel• Ensure that GENERATOR 1 is selected in the menu bar.
• Select “WAV” 2 with the rotary wheel.
• Press “Enter”.

 A selection menu appears.
• Select the desired test signal with the rotary wheel.
• Press “Enter”.

1
2

 You have now selected the test signal.

 You have now selected the test signal.

19

Operation

Setting the Parameters
You have two possibilities for setting up the parameters for thetest signals. You can use either the direct buttons or the rotary
wheel.

Setting parameters using the rotary wheel• Turn the rotary wheel.

 The selected parameters will be marked with a black bar.
Setting parameters using the direct buttons• Press the “Level” or “Freq” button.

 You have selected the desired parameter.
• Turn the rotary wheel to set the parameter.
• Confirm the setting with the “Enter” button.

 You have now set up the parameter.
• Confirm your choice with the “Enter” button.

 The parameter display blinks.
• Turn the rotary wheel to set the parameter.
• Confirm the setting with the “Enter” button.

 You have now set the parameter.
20

Operation

Setting the Sensitivity of the Rotary
Wheel
You can set up the sensitivity (step size) of the rotary wheel. To
do this, proceed as follows:• Select Level
or Frequency• Hold down the “Sens” button.

with the rotary wheel.

 The current sensitivity of the rotary wheel will be displayed
1 .

• Turn the rotary wheel to set up the desired sensitivity.
• Release the “Sens” button to accept the desired sensitivity.

1 You have now changed the sensitivity of the rotary wheel.

21

Operation

System Settings
You can adjust various system settings of your instrument. To
do this, switch to System 1 in the menu bar using the rotary
wheel and confirm with “Enter”.

Power Save
The Power Save mode switches the instrument off if no button
has been pressed within an adjustable time period.

The possible system settings are displayed:• Use the rotary wheel to select the Power Save function

2.
• Confirm the selection with the “Enter” button.
1
2
3
4
5

 The display starts to blink.
• Turn the rotary wheel to set the desired time.
• Confirm the entry with the “Enter” button.

 You have now changed the switch-on time of the PowerSave mode.

22

Operation

Backlight
You can choose between “Auto” and “Manual”.
Auto

The backlight will be switched on automaticallyduring operation, and will be switched off again
after a period of time.

ManualPress the “On/Off” button to switch the background lighting on and off.

• To do this, select the Backlightwheel.
• Press “Enter”.

3function with the rotary The display now changes between “Auto” and “Manual”.

Firmware
Display of the version number, with the possibility of carryingout an update for the MR-PRO 4 (see chapter “Updating the
Firmware”).

Display of the Serial Number
You can read out the instrument’s serial number
bottom line.

5

from theSetting the Contrast
Changing the contrast of the screen display.
To do this, proceed as follows:• Hold down the “ESC” button and turn the rotary wheel until
the desired contrast is obtained.

 You have now changed the contrast of the screen display.

23

Operation

Configurations (MR-PRO only)
With the MR-PRO, you can store your current instrument settings
as configurations, and can call these up again at a later date.

• Select a memory location with the rotary wheel and store
your configuration by confirming the selection with “Enter”.

Storing configurations
10 configuration storage locations are available to you.
• Using the rotary wheel, select CONFIG in the menu bar.
• Confirm with “Enter”.

 You have now stored the current instrument settings as a

 The following menu is opened:

configuration.

In order to easily remember configurations you may rename them.
For altering the file names, connect the
MR-PRO to a computer via USB and rename
the files in the CONFIG folder. Only the first
10 configurations are shown in the display.

• Select STORE and confirm with “Enter”.

 The following selection menu is opened:24

Operation

Calling up Configurations• Use the rotary wheel to select CONFIG in the menu bar.
• Confirm with “Enter”.

Transferring Configurations to another Device (MR-PRO)With the MR-PRO, you have the possibility of transferring
stored configurations to another device.

 The following menu is opened:• Connect your MR-PRO to a computer via USB.

 A removable memory drive will be indicated on thecomputer.
• Select the CONFIG sub-folder.
• Select “Recall” and confirm with “Enter”.
• Select the desired configuration in the Selection menu andconfirm with “Enter”.

 You have now loaded the desired configuration.

 You will see the stored configurations of your MR-PRO.
• Copy this data to your computer.
• Connect another MR-PRO to the computer via USB.
• Copy the previously copied data into the CONFIG sub-folder
by overwriting the data therein.

 You have now transferred configurations from your MRPRO to another MR-PRO.

25

Test Signals

5. Test Signals

Sweep

Sine

Characteristics and use
Pure sinusoidal signals are required for almost every audio
measurement. The Minirator provides a wide and adjustable
output level range and selectable output frequencies.
Parameters
Output level
Output frequency

26

Characteristics and use
Sweep signals with a resolution of up to 1/12 octave can begenerated over a freely selectable frequency range. An audio
analyzer like the Minilyzer from NTi Audio can automaticallytrigger to this signal sequence to measure the frequency response.
Starting the Sweep Signal• Select the “START” symbolwith the rotary wheel.

 You can interrupt a running sweep via the „STOP“symbol.

Test Signals

Sweep Signal Modes
Using the “MODE” symbol, you can run the test signal in thefollowing modes:
Once-only

Plays the test signal once

Continuous

Repeats the test signal after an adjustable
pause (tPAUSE).

ff STOP
B
A

f RES

1 kHz
t STEPt TRIG

Parameters
Output levelf STARTt

The frequency display is for information only. The
current frequencies will be displayed here once the
SWEEP test signal has been started.
A

The sweep recording starts as soon as the frequency
drops from 1 kHz to fSTART.

B

The end of the sweep will be signaled by a falling frequency.

You can configure the signal sequence here.

27

Test Signals

Chirp

Chirp Signal modes
Using the “MODE” symbol, you can run the test signal in thefollowing modes:
Once-only

Plays the test signal once

Continuous

Repeats the test signal after an adjustable
pause (tPAUSE).

Parameters
Characteristics and use
A Chirp is the name for a signal whose frequency continuallychanges over time (also known as continuous sweep). It is used
for the recording of frequency responses, the measurement of
impulse responses and the acoustic assessment of rooms.

Output level

Starting the Chirp signal• Select the START
symbol with the rotary wheel.

You can configure the signal sequence here.

 If this is activated, it turns into a STOP symbol
will end the test signal when selected.

28, whichThe frequency display is for information only. The
current frequencies will be displayed here once the
CHIRP test signal has been started.

Test Signals

fDelay Test

t CHIRPf STOPt SCALE = LIN

t PAUSEt SCALE = LOG
f STARTt

Fading in and out of any Chirp signal generates spurious frequency components,
leading to ripple in the frequency response.
The Chirp sequences of the MR-PRO / MR2
are optimized for ripple of ± 0.2 dB maximum.
Parameter combinations resulting higher
ripple are automatically corrected during input.

Characteristics and use
The Delay Test signal is a specially configured Chirp signal. It
enables to setup delay lines in combination with the NTi Audio
Acoustic Analyzers. You can find further information in the application notes and user manuals of acoustic analyzers.
Parameters
Output level29

Test Signals

Pink Noise

Operation
You can choose between the following test signal modes with
the MOD setting 1 :1

CONTGenerates a continuous test signal.

2

Characteristics and use
The Pink Noise test signal has a high spectral density, an infinite
period (> 100 years) and 20 kHz bandwidth. Pink Noise is used
as a reference signal for the layout of loudspeaker systems(PA systems), whereby a Real Time Analyzer (RTA) is used to
execute the required measurements.
When operated in the intermittent mode, Pink Noise forms thebasis for reverberation time measurements.

30

Generates an intermittent test signal.
You can determine the cycle times of the intermittent signal with the CYC setting 2 .
(3/3 = 3 seconds of signal and 3 seconds pause.)
These settings have no effect in the continuous
mode.

Parameters
Output level

Test Signals

White Noise

Polarity

Characteristics and use
The White Noise test signal has a high spectral density,
Gaussian amplitude distribution and an infinite period (> 100
years). White Noise is used for all measurements with FFTanalyzers, and has a constant signal power per Hertz and a
20 kHz bandwidth.

Characteristics and use
The sawtooth test signal is ideally suited for checking the polarity of loudspeakers. The NTi Audio analyzers detect this signal
and determine the polarity.

Parameters
Parameters
Output level

Output level
The frequency display is for information only. The frequency cannot be adjusted.

31

Test Signals

Wave File Player (MR-PRO only)

1
2

Characteristics and use
You can play back your own test sequences with the MR-PRO.
The test sequences will be repeated automatically and withoutpauses. For a better overview, Wave files are organized in subfolders.
The MR-PRO is already equipped with a series of demo sequences in the WAV file format. You can create a link to a computer at any time via the USB interface and can exchange existing wav-files or add new ones.

32

Possible applications
Possible applications include, for example:• Identification generator in the broadcasting sector• Musical signals for the assessment of PA systems• Playing back complex test signals
Selecting a folder• Select the Symbol folder 1 with the rotary wheel.
• Confirm with “Enter”.
• Select the desired folder with the rotary wheel.
• Confirm with “Enter”.

 You have now changed the current playback folder.
Selecting a Wave file
• Use the rotary wheel to select the Symbol file 2 .
• Confirm with “Enter”.
• Select the desired WAV file with the rotary wheel.
• Confirm with “Enter”.

 The wav-file will be played.

Test Signals

Default WAV-files
The factory default wav-files are• Ansagen:			
• Messages:						• Signals:
				• Sounds:
			
			
			
			

Anpassen (German)		
Testsequenz (German)
Adjust (English)
Occupied (English)
Test sequence (English)
Fast Pink Noise 1s
Fast Pink Noise 4s
NTi Audio STIPA
Drum1
Drums2Hihat
Sax
Synth1

Loading your own wav-files
Wave files for the MR-PRO must fulfill the following requirements:• 48 kHz sampling frequency• Mono / Stereo• 16 Bit resolution

If a wave file does not meet the requirements, the playback stops and the “Mute”
button lights up continuously red. Wav-files
can be converted to the above requirements
by a free software available for download atwww.nti-audio.com.
To load WAV-files, you will need a computerwith the following minimum specifications:• PC with Windows 98SE
• Macintosh computer with OSX

Further customized wav-files are available for download on the
Minirator support page at “https://my.nti-audio.com”.

Copyright
NTi Audio delivers a set of wave files with
the MR-PRO. These wave files may only
be replayed with an NTi Audio instrument(MR-PRO). Any further usage is forbidden.

• Connect the MR-PRO to the computer via USB.

 The MR-PRO appears on your computer as a removabledata medium.

33

Test Signals• All the sub-folders in the “Wave” folder
now appear in the folder selection 1 .
Add additional sub-folders to this folder
level as required.
• If necessary, you can make use of theother standard possibilities of a removable data medium. For example, you cancopy wav-files from the MR-PRO onto
your computer or delete unnecessary
files.
• The absolute level generated at the output depends on the modulation as wellas the signal form of the data present in
the WAV file.
• Example: A fully modulated sinusoidal
signal played back at 0 dBF generates anabsolute level of 18 dBu at the output.

WAVE

Folder1

Folder2• Signal1.wav• Signal2.wav• ...

• Signal1.wav• Signal2.wav
• ...

...

Parameters
Output level
The output level of this test signal is adjusted indBF (dB full scale) or %.

• Open the “WAVE” sub-folder on the removable medium• Open one of the sub-folders in the “WAVE” folder.
• Copy the desired files into the folder.

 You have now loaded your Wave files.
34

Meas. Functions (MR-PRO only)

6. Measurement Functions
The MR-PRO offers the following measurement functions:

Menu

Measurements

Generator

Impedance
Phantom Power
Balance

Cabletest

XLR cables
Phantom Power

Impedance

Impedance + Phase
Apparent Power + Phase
Phantom Power
Balance

Impedance Test in Generator Mode
The MR-PRO measures phantom voltages and displays impedances and the impedance balance in the SINEWAVE operating mode. Using the SINEWAVE sinusoidal test signal, the
MR-PRO measures the load connected to the output between
PIN 2 and 3 (RL=R2+R3). The measured values of R2 and R3
will be displayed by selecting RL with the rotary wheel.
If only R2 or R3 can be measured, RL is replaced by R2 or R3
accordingly.

In the case of balanced connections (XLR), interference radiated onto
the receiver side will be eliminated.
For this to work there must be a balanced
impedance distribution on both signal lines.
In the case of unbalanced impedance distribution, signal interference could occur.
The MR-PRO allows you to test the connections for balance.

35

Meas. Functions (MR-PRO only)

Balance Display

RCA

The balance display allows localizing a number of typical faults,
such as short-circuits and defective cables.

MR-PROIn the case of an unbalanced impedance distribution, the display arrow points to the pin with the higher impedance.

2
1
3

R2
R3

Balanced impedance, R2 = R3

XLR
Unbalanced impedance, R3 > R2

The impedance and balance measurement
can only be carried out down to a definedminimum level. If the measurement cannot
be carried out, the display shows:36

Unbalanced load relationships can be analyzed further by selecting the impedance display with the rotary wheel. If the impedance cannot be measured, the display shows “---” insteadof the measurement value.

Meas. Functions (MR-PRO only)

Measuring Phantom Power Voltages
The phantom voltage is necessary in connection with capacitor microphones in order to operate the impedance converter
located in the microphone as well as for some “active” directboxes.
Mischpult

MR-PRO+48V

2 x 6.8kΩ
2
V2
V3

1
3

R2

1

R3

XLR

The most common phantom voltage is 48 V and lies on bothPin 2 and Pin 3 with balanced impedances (see diagram).

Unequal phantom voltages on Pin2 and Pin3 of the XLR cableindicate an error and will be displayed by the blinking of thephantom voltage display (DC).
You can localize the faulty voltage source by selecting the DC
function 1 with the rotary wheel.

37

Meas. Functions (MR-PRO only)XLR Cable Test
The MR-PRO supports a cable test function that quickly detects damaged XLR cables.
The cable test is based on an impedance measurement. In order to indicate a correctly wired XLR cable, the test routine of
the MR-PRO assumes the following impedances on the output:

MR-PRO

2.

MR-PRO or adapter

2

Cable
R2 = 1k

1

R3 = 2k

3

XLR
Out

38

To test a cable, proceed as follows• Select the “Cable test” function in the menu.
• Plug the XLR cable into the XLR output (1).
• Plug the other end into the XLR input (2).

XLR
In

1.

Meas. Functions (MR-PRO only) The following is displayed on the screen:

The cable has not been
plugged in correctly. Check thecable connection.

The tested cable is defective,
the pins 2 and 3 are crossed.
Other error indications may appear depending on the cables
fault.

Cable Test Plug
For long cables already in place, NTi Audio
offers an optional adapter named “Cable
Test Plug”. Plug one end of the cable into
the Cable Test Plug and the other end of thecable into the MR-PRO.
Order information:
Cable Test PlugNTi Audio # 600 000 311

The tested cable is OK.

39

Meas. Functions (MR-PRO only)

Impedance Test
The impedance test supports the verifications of distributed
loudspeaker installations and shows detailed information of
the connected load.
Connect any unpowered load between Pin 2 and 3 of the XLR
output for best performance.

Damage caused by high voltage
Never connect the instrument to a power
output or any activated distributed speakersystem!

70V/100V Protection for MR-PRO
Protects the Minirator MR-PRO against accidentally applied 70V/100V voltages during
impedance or power testing at distributed
speaker systems.
NTi Audio # 600 000 313

40

Display Modes

1
2

In the mode |Z| + Phase 1 the absolute value of the impedance and the phase is shown.
Based on the measured impedance, the apparent power 2
which the load would sink when driven with a defined reference voltage is calculated and displayed.

Taking a Screenshot
A screenshot may be stored in the MR-PRO
memory for documentation of the measurement results. See chapter “Screen Display”
for details.

Meas. Functions (MR-PRO only)

Impedance

Power

2
1

3

How to measure• Connect the load between Pin 2 + 3 of the XLR.
• The absolute value of the impedance 1 , the phase 2 andwhether the load is inductive or capacitive 3 is displayed.
The output level and frequency may be adjusted as describedearlier in this manual.
If the load is connected unbalanced (e.g. between pin 1 + 2), a“2” or “3” is displayed below the “IMP” symbol.

1
2

3

How to measure• Select the reference voltage of the distributed loudspeakersystem 1 with the rotary wheel.
• Connect the load between Pin 2 + 3 of the XLR.
• The apparent power 2 in VA (Volt Ampere) and the phase
information 3 is displayed.
Selection of Phase / Power Factor readout• Select “PHS” and press “Enter”.
• The power factor PF = cos (phase angle) is displayed.
• Press “Enter” again.

 You have toggled between Phase and Power Factor display.
41

Screenshot

7. Taking a Screenshot
You may take a screenshot of the Minirator MR-PRO display
and download it to your computer for reporting. Follow this
instruction:• Connect the Minirator MR-PRO via USB to the computer.

 The MR-PRO will show up as a drive on your computer.
• Create a new folder “Screen” in the root of Minirator drive.
• Disconnect the USB cable from the computer.
• Simultaneously press the On/Off button and the Enter button shortly on the Minirator MR-PRO.

 The MR-PRO screenshot has been saved in the folder“Screen”.
• Connect the Minirator MR-PRO via USB to the computer
again.
• Download the screenshot for your reporting.

 Congratulations, you have taken a screenshot.

42

Updating the Firmware

8. Updating the Firmware
You can find the installed firmware version of your instrument
as follows:• Select “System” in the menu bar.
• Confirm the selection with the “Enter” button.

 The firmware version of the instrument will be displayed.
The firmware update is carried out by connecting your Minirator to a computer via USB and running the PC application
software “MR-Update”.

In order to update the firmware, you willneed a computer with the following minimum specifications:• PC with Microsoft Windows 2000 ornewer• USB termination• Connection to web

Instructions:
1. When updating your Minirator for the first time
• Register your instrument at https://my.nti-audio.com (seechapter “Further information”). After the registration you
will get the following details at the support page:-- Firmware update instruction-- Overview of new firmware features• Download the software “MR_Up-date“ at the Minirator
support page.
• Install and run “MR_Up-date“• Follow the instructions shown in “MR_Up-date“.
2. If you have already updated your Minirator before• Switch your computer online.
• Run the software “MR_Up-date“, which automatically checks
the NTi Audio website for any new firmware available. No
further manual download is required.
• Follow the instructions shown in “MR_Up-date“.

 You have updated the Minirator firmware.

43Troubleshooting

9. Tips and Troubleshooting
Resetting to the Factory Settings

Behavior with low-impedance Loads

If the Minirator reacts unexpectedly, a reset to the factory settings might solve the problem.

The maximum output current of the MR-PRO is 10 mA. If theconnected load consumes more current, the internal regulationof the MR-PRO reduces the output level. This condition will be
indicated by a flashing output level display:.

• Switch the instrument off.
• Hold down the “ESC” button and simultaneously operate
the “On/Off” button.

 The confirmation of the reset is displayed on the screen.

Reloading WAV-files (MR-PRO only)
You can reload the wave files of the MR-PRO that were installed in the factory.
The files are available at the Minirator support page“https://my.nti-audio.com”.

44

PC recognizes Minirator as GPS Camera
The MR-Update Software may not recognize the Minirator at
PCs with Windows 7 installation.
• Open the device manager.
• Select with the right mouse button the GPS Camera driver,select “Properties“ -> “Driver” -> “Update Driver”.
• Select „Search the compute for driver software“.
• Select “Select driver from list …”.
• Select Minirator driver “atm6124.sys ATMEL AT91xxxxx
Test Board“.
• Complete the Minirator driver installation.

Troubleshooting

Faults and their Correction
Fault

Fault finding

The Minirator does not gener- “Mute” button blinks.
ate an output signal.
“Mute” button lights up
continuously.

Cause

RemedyYou have switched the
instrument to Mute.

Press the “Mute” button.

You have called up the “Pink
Noise” (PNoise) test signal or
you are in the Pause cycle of
the Chirp test signal.

Wait until the pause has
ended.

Non-supported Wave format.

Load a supported Wav-format.

Press the “Start” button.

Cable not plugged in correct- Plug in the cable correctly.
ly.
Screen contrast poor.

Contrast needs to be
adjusted.

Press “ESC” and operate therotary switch to set thecontrast.

MR-PRO: Wave files are notplayed back

“Mute” button lights up
continuously.

Non-supported Wave format.

Load a supported Wave format.

MR-PRO indicates noimpedance.

The lowest line is not
displayed.

Output level too low.
Incorrect test signal.

Increase the output level.
Change to the SINEWAVE
test signal.
45

Further Information

10. Further Information
My NTi Audio
Register your instruments at My NTi Audio and benefit fromthe following possibilities:
•
•
•
•
•
•
•

46

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“.

 Congratulations, your NTi Audio product is registered.

Further Information

Warranty Conditions

Calibration Certificate

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.

Your NTi Audio instrument has been carefully tested during
production and corresponds to the specifications listed in“Technical Data”. Calibration certificates for new products are
optional.

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.

NTi Audio recommends annual calibration of the products after the purchase. The calibration provides documented andtraceable measurement accuracy and confirms that yourNTi Audio product meets or exceeds the published specifications. The calibration and adjustment procedures follow the
documentation and traceability requirements of the standard
EN ISO / IEC 17025.
For calibrations kindly follow the service guidelines atwww.nti-audio.com/service.

Service and Repairs
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.

47

Further Information

Declaration of Conformity

Information for Disposal and Recycling

CE / FCC Compliance Statement
We, the manufacturer NTi Audio AG, Im alten Riet 102, 9494
Schaan, Liechtenstein, do hereby declare that the Minirator MR2 and Minirator MR-PRO products, approved in 2007,
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.
Date: 25. July 2019

Position: COO
48

Dispose of your instrument in accordancewith the valid legal environmentally regulations in your country.

Regulations for the European Union 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 thelegal regulations.

Other countries outside the EU:
Contact your respective authorities for waste disposal and follow their regulations.

Technical Data

11. Technical Data Minirator
MR2
Outputs

MR-PRO
Balanced XLR, unbalanced RCA
phantom power resistant

InputsDC power supply, USB

Signal Wave Forms

Sine, Polarity Test Signal, Delay Test Signal,
White Noise (crest factor, PAR* = 3.05 (9.7 dB), 5 Hz - 22 kHz),
Pink Noise (crest factor, PAR* = 4.5 (13.1 dB), 5 Hz - 22 kHz),
Gated Pink Noise (1 - 9 seconds), Wave File playback (MR-PRO)Default wav-files

DC power supply, USB
XLR for cable test

Fast Pink Noise 1s (PAR* = 12.5 dB)
Fast Pink Noise 4s (PAR* = 13.1 dB)
NTi Audio STIPA

Wave File Format

Sampling frequency:
Resolution:
Output level:

Frequency Setting

Range:
Increment:
Accuracy:

Stepped Sweep Function

Frequency range:
Increment:
Sweep speed:

freely selectable
1/1, 1/3, 1/6, 1/12 octave
selectable 0.5 to 5 seconds

Continuous Sweep (Chirp) Function

Frequency range:
Increment:
Chirp speed:

freely selectable
Linear / Logarithmic
1 to 99 seconds per cycle

Level Setting

Units:
Increment:* PAR = peak-to-average ratio

48 kHz16 Bit, Mono / Stereo
0 dBFS = 18 dBu (sine) acc. to EBU R68
10 Hz to 20 kHz
in 1 digit steps
0.01%

dBu, dBV, V
in 1 digit steps

dBu, dBV, V, dBFS, %in 1 digit steps (e.g. 0.1 dBu)

49

Technical Data

Output Level Ranges

Sine, Sweep, Chirp
White Noise
Pink Noise
Polarity, Delay Test

Flatness

RL ≥ 600 Ohm

Accuracy @ 1kHz
THD+N

22 Hz to 22 kHz, average,@ 1 kHz, typical

Output Impedance
Impedance Measurement

MR2

MR-PRO–80 dBu to +8 dBu–80 dBu to +0 dBu–80 dBu to –2 dBu–80 dBu to +6 dBu–80 dBu to +18 dBu–80 dBu to +10 dBu–80 dBu to +8 dBu–80 dBu to +16 dBu±0.5 dB±0.2 dB @ 10 Hz to 12 kHz–0.1 dB / +0.3 dB @ 12 kHz to 20 kHz±0.5 dB±0.2 dB–90 dB (0.0032%) @ 8 dBu,
Noise floor typ. 25 μV–96 dB (0.0016%) @ 18 dBu,
Noise floor typ. 15 μV

200 Ohm (balanced)

12.5 Ohm balanced, Imax = 10 mA

Method:Measurement range:

Absolute value Z
4 Ohm to 50 kOhm (pin 2-3)
2 Ohm to 25 kOhm (pin 1-2 or 1-3)
@ f = 30 Hz to 10 kHz (Sine)@ Level from –20 to +18 dBu±10% or ±2Ohm (whatever is higher)

Accuracy:
Power Calculation

Reference voltage

25 V, 35 V, 50 V, 70.7 V,
100 V, 140 V, 200 V

Phantom Voltage

Measurement range:
Accuracy:

0 to 54 V±3 % or ±0.5 V

USB Functionality
Flash Memory
Signal Balance Accuracy @ XLR-Output
Display
Auto-Power-Off
Batteries
50

Firmware update

Firmware update
Mass Storage Device
512 MByte for storing wave files andconfigurations≥ 99% @ 1 kHz for output levels above -20 dBu
Graphical, with back light
10, 30, 60 minutes or OFF
3 x AA Alkaline dry cells or rechargeable equivalents

Battery Life

0 dBu, no load, typical

MR2

MR-PRO

14 hours

8 hours

Temperature Range
Humidity

0° to 45° C (32° to 113° F)< 90% relative humidity, non-condensing

Protection Rating
ATEX
Dimensions (LxWxH)
Weight including Batteries

IP51
For applications in explosive atmospheres withinzone 2 in accordance with IEC 60079; conforms to 2014/34/EU
147 x 74 x 41 mm

152 x 81 x 43 mm(incl. protective shock jacket)

250 g (9 oz.)

310 g (11 oz.)4000 td 01.18