This is a free frequency spectrum that I have developed for my music app. I used it to test on my keyboard and get very accurate reading. Place your finger on the spectrum to get the respective frequency. It has an accuracy of /- 5 Hz.
It has an auto peak detection on the graph in red dot and the maximum frequency value to top right.
To be release musical app that uses this spectrum is
1. Power spectrum with Cepstrum to find fundamental frequency. https://play.google.com/store/apps/details?id=com.appspot.harmoncepstrum release on 040215
2. Piano spectrum. Published under app name Polyphonic Pitch Detector.
https://play.google.com/store/apps/details?id=com.appspot.harmonpiano released on 270115
3. Spectrogram for midi note 030515 https://play.google.com/store/apps/details?id=com.appspot.musictranscription
9Apps 4.9
