SoundAnalyzer is good audio analyzer of operativity using the voice from the microphone built into your smartphone, and can display waveform and spectrum simultaneously.
It is possible to use it without accessory, so you can use it easily anytime and anywhere.
It will operate immediately after making it start.
SoundAnalyzer is the charged version of SimpleFFT. RESONABLE PRICE！

The contents of a functional addition from the free version (SimpleFFT)
・It adjusts automaticaly to various screen resolution of　800×480 or more.
・sample rate(Hz):8000,11025,16000,22050,32000,44100,48000 (It is dependent on your model)
・freqency axis: logarithm / linear (It can be canged by flick operation)
・window function：Rectangular、Han、Hamming、Blackman
・Vertical and horizontal display range can be changed by the Flick operation.
・The size of each area is changed by flipping the up-and-down jump-off line.

Since it will be introduced by youtube soon in order to show the function and the usage.
You can have a look this application there!

Keyword: waveform, spectrum, FFT, real-time audio analyzer,sampling frequency