**A MIDI device is required for this application. A user must have a piano keyboard that supports MIDI plugged into their phone to be able to use this application** What is MIDI? Many modern electronic piano/keyboard pianos have MIDI output, where pressing and releasing keys sends a digital signal. This digital signal is able to distinguish which key was pressed. This is much more accurate than using audio to determine the pitch of a note that was pressed. How to use this app? With a MIDI de