Spectrum Analyze gives you real-time spectrum data from the microphone on your Android device.

Features in Free Version
* No Ads
* 44100 Hz sampling rate 
* Max frequencies up to 22050 Hz (1/2 sampling rate)
* 8192 samples per spectrum 
* ~5.4 Hz Resolution per point
* Peak Detect of whole spectrum and your local window
* Pinch to Zoom
* Tap to Pause
* Max Hold
* Take Screenshot
* Share on Facebook, Gmail and many more

Features in Premium Version. 
* Limited time 99 cent app! Will increase price as more features are added.
* Help out the developer to keep adding more features!
* Beta Log Frequency Scale
* Adjustable sample rate from 8000 Hz to 48000 Hz
* Max frequencies up to 24000 Hz (1/2 sampling rate)
* Adjustable Size of FFT up to 100000 samples
* Not limited on Power of 2 sized FFTs (Must be even though)
* Autoscale
* Adjustable Manual Scale

If you purchase the app and don't like it contact me for a refund.

Contact on Reddit:  Raspberrywood

Spectrum Analyze gives you real-time spectrum data from the microphone..