App: NAK T-100 Audio Analyzer
Developer: Chen Wang
Genres: Utilities, Entertainment

NAK T-100 is a lightweight and all-inclusive audio analyzer for inspecting analog audio devices on computer. It is capable of performing 7+ conventional audio measurements in a single setup without swapping a stack of physical instruments. This makes it an agile tool to quickly check whether a given audio device performs to its specifications. Or during a service/repair/modify project, this is a less overkill yet more cost-effective tool for conducting general audio measurements on desk top. Some of the key functions are specifically optimized for tuning analog tape players/recorders.

The app features modern DSP core with traditional analog skin. It adopts the "Skeuomorphism" design philosophy to offer era-specific operational experience in working with analog audio devices. However, the underlaying engine works purely from digital domain after all, which does not have to follow the analog measurement principles and yield strict identical readings. Typical tolerances across typologies of test instruments should be expected.

Features and Specifications
[Generator]
  21 spot sinusoidal plus white, pink noise and square wave
[Level]
  -80dB ~ +10dB 
  (extendable to +30dB with physical input attenuator),
  RMS or peak, 0dB = 1.0V (after calibration)
[AC Volt]
  10mV ~ 300mV, 0.1V ~ 1V,
  1V ~ 10V (with physical input attenuator)
  20Hz ~ 20kHz
  Requires calibration with reference AC volt-meter
[THD+N]
  0.01% ~ 0.3%, 0.1% ~ 3%
  400Hz/1000Hz
[Speed]
  3000Hz/3150Hz ±3%
[Wow & Flutter]
  0.01% ~ 0.3%, 0.1% ~ 3%
  Quasi-Peak (DIN 45507)
  WRMS (JIS)
  Peak unweighted
  RMS unweighted
  Spectrum display: 0.2 ~ 100Hz
[Signal/Noise Ratio]
  -100dB ~ -10dB
  IHF-A weighted
[Frequency Response]
  20 ~ 20kHz (extendable to 26kHz at 96kHz sample rate)
  -100dB ~ +10dB
 White noise
  Pink noise
  Sweep frequency (asynchronous)
[Lissajous]
  Ellipse figure with time stabilizer
[Oscilloscope]
  Two channel, non-quantitative
[Meter Ballistics]
  RMS: 300mS
  Peak: 10mS raise, 2000mS fall
[Sound Card]
Must have standard stereo input and stereo output, sample rate
 44.1kHz ~ 96kHz (higher sample rate may work but without 
 guarantee)

Please note:
1. This app is by no means a replacement of laboratory grade instrument.
2. This app is intentionally designed in favour of simplicity and convenience without excessive configurability.
3. This app operates in two switchable modes: Basic and Scope.
4. The Basic mode is the primary working mode. Its UI panel may be unfamiliar to new users at first. But the same ergonomics has been repeatedly proven in the former practices.
5. The Scope mode is a GUI add-on that displays complex measurement results in 2-dimensional plots. It is a lite graphic console without a set of pro implications.
6. The specifications may vary depending on actual sound card used.
7. Calibration will be needed prior to working with a specific audio device on a specific computer.
8. The computer must have standard stereo audio input (line-in) and standard stereo audio output (regardless of built-in or external) in order to allow the app functioning properly.
9. Sound devices that have uncommon channel layouts need to be configured for re-mapping the selected channels to the standard stereo channels by using tools outside of this app.
10. Relatively faster computer with less busy multi-tasking workload is recommended.

Release notes:
Minor bug fixes.