I just wrote how to Turn a Tablet into a Signal Generator. In addition to generating signals, a tablet can be used as audio signal analysis. Typically the only way to get sound into those tablets and smart phones is through built-in microphone, which can be limiting. Here are some Android software for audio signal analysis software I have tried:
SimpleFFT is a real-time Fast Fourier Transform analyzer(audio analyzer) in the low-frequency region using the voice from the microphone built into your smartphone or tablet. This is a simple application that just shows the waveform and spectrum of the audio signal up to around 5 KHz. Here is a screen-shot of the application screen from Google Play shop (for some strange reason the image on the store is like this):
Spectral Audio Analyzer is a Free real-time audio analyser with 8 kHz spectral bandwidth. Display any sort of audio from the microphone as a coloured spectrogram. The programs says it can be used to identify environmental noise, search for annoying tones, view harmonic patterns of instruments and voices and analyse the frequency range of your speaker. In some applications this spectrogram view is more useful than just FFT display. The free version software has most configuration options disabled (works as advertisement for commercial version), but looks something that could become useful. Here is a screen shot:
TRA Audio analyzer claims to turn your Android phone into a professional audio analyser. The free version supports one, 1/2 and 1/3 octave filter and calibration (commercial professional version has more options). This software can be used to measure the frequency response of your audio equipment, identify tones and noises. Or I can think you could have your tablet sitting on your audio console and see trends as they develop before they become problems. I wish I have had this kind of tools at hand years ago when I worked more with PA systems.
The interesting idea on this software is the calibration to linearize the frequency response your smartphone / tablet audio input (mic or line in): for proper calibration you only need to supply a steady pink noise signal (you can get this of course from test CD, but software documentation says that background noise on quite place can work as pink noise source).
Here was my list of free applications I have tried. I also found some promising looking applications that you need to pay money for. Hare is my list of interesting looking application that you need to pay some money (and I have not tested):
AudioTool – SPL (deciBel) Meter featuring RT60, Spectrum Analyzer, Spectrogram, Chart Recorder, Signal Generator, Polarity Checker. Two methods of Mic calibration are offered. Recommended by “Sound and Vision” magazine.
SPL and Spectrum Analyser software says to give SO 1/3 Octave bars and Spectrogram.
SPL Meter says to be a professional-grade sound level meter, also known as a decibel or dB meter, on Android device.
FFT claims to be a professional-level RTA with mic calibration.