Easy Piano Tuner is a professional piano tuning program for Android. Unlike regular chromatic tuning apps that simply tune to a pre-calculated equal temperament, this app actively measures the tonal characteristics of each note and automatically calculates an ideal "stretch" or offset from equal temperament. In other words, it finds the best compromise between intervals like fifths, fourths, and octaves, the way aural piano tuners do when fine-tuning a piano.
There are three levels of functionality: a free (evaluation) version, a paid "plus" version with basic tuning functionality, and professional version with features geared towards professional piano tuners. The extra functionality is unlocked through one-time in-app purchases.
The Free version includes the following functionality:
• Tuning functionality for the mid-range of the piano only
• Automatic note detection
• Ability to measure each note on the piano to see how its current tuning compares to the ideal tuning curve (see if a piano is roughly in tune)
• Swipe in the graphing area to show a live frequency spectrum or the inharmonicity of measured notes.
Upgrading to "Plus" adds the following functionality:
• Tuning functionality for the entire piano
• Tune to frequency standards other than A=440
• Calibrate device to an external frequency source
Upgrading to Professional unlocks all features of the "Plus" version, plus the following:
• The ability to save and load tuning files, so a piano doesn't need to be re-measured each time it is tuned
• Pitch raise mode that calculates overpull for an initial first pass "rough" tuning (for pianos that are extremely flat)
• Access to all future features and enhancements
Free to Plus (approximately US$20)
Free to Pro (approximately US$100)
Plus to Pro (approximately US$80)
Note about permissions: This app requires permission to access the microphone on your device and permission to read and write files.