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Sinusoid Pty Ltd
In stock

Audio Kit


Latest Release is 2.2.1 - May 2020

Audio Kit is a collection of four tools which are essential for those working in audio, sound and music. A real time Spectrum Analyser, a Scope to display waveforms, an SPL (Sound Pressure Level) Meter, and a Signal Generator producing sine waves, white noise and pink noise. A sine wave sweep generator is available with In-App purchase.

Demonstration Video of Audio Kit

  • View a real time spectrum of audio with the Spectrum Analyser and identifying peak frequencies 
  • iPhone audio analyser
  • View the actual waveform of the audio signal with the oscilloscope 
  • An SPL Meter provides measurement of sound levels using an A-weighting.
  • The Signal Generator provides a sine wave output up to 20,000Hz in 1 Hz steps, along with noise generators for white and pink noise and sweep generator.



FFT (Fast Fourier Transform) is used to calculate the frequencies in the Spectrum Analyser and these are displayed in real time. The frequency is displayed in either logarithmic or linear scale.

  • Three FFT sizes of 8192, 4096 and 2048 are selectable, giving fine resolution of frequencies.
  • 6 different FFT window function types can be selected - Hamming, Hann, Rectangular, Bartlett, Triangular and Blackman.
  • Number of FFT windows can be selected from 1 through 4.

The strongest frequency is displayed both above the peak, and optionally, in a large number display in the center of the screen. The large number display can be quickly switched on or off by double tapping the screen.

There is a screen capture facility in the Spectrum Analyser allowing you to save the spectra  for future reference along with details of the FFT parameters, time and date.

A single tap freezes the screen. Other features such as screen capture and double tap to toggle large number display still work during the freeze. This feature can be turned off in preferences if it’s not desired.

For a great, intuitive introduction for the Fourier Transform, have a look at this youtube video



The display of the Scope can be adjusted easily using pinch gestures in both horizontal and vertical directions.

Zero crossing detection of the waveform provides a smooth display and can be set to either positive or negative direction zero crossing.

There is a screen capture facility in both the Spectrum Analyser and the Scope allowing you to save the spectra and waveforms for future reference.


SPL Meter 

The SPL Meter continuously displays the sound pressure level, and has resettable minimum and maximum displays also.

SPL meter has a continuous ticker style trace of the SPL over time.

The SPL Meter can be calibrated against a reference SPL meter or a reference sound source.


Signal Generator

The output of the Signal Generator can be viewed on the other parts of the App.

The Signal Generator has 3 different output types: 

  • Sine wave
  • White noise
  • Pink noise
  • Sweep (IAP)

The output of the Signal Generator can be viewed on the other parts of the App.

The sine wave frequency selected using picker wheels allows for accurate control of frequency to within 1Hz. Volume for the sine wave and noise signals is continuously adjustable.

If the sine generator is running, the frequency is shown in a badge on the Sig Gen tab. Likewise the type of noise is shown here if noise is running.

Sweep generator can sweep frequencies in either direction, and for variable time. The sweep generator can produce a sweep of sine waves from very short duration up to 20 seconds in length. The sweep of frequencies can be increasing or decreasing and be of linear or logarithmic function.



All of the user preferences in each of the above applications can be made persistent between restarts of the App.

All parts of the App have direct access to a context sensitive help document.


Audio Kit - essential for those working in audio, sound and music.


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