A software solution to the pitch limitations inherent in the MIDI standard. The invention uses the Polyphonic Aftertouch (also known as "Key Aftertouch") messages available in the basic MIDI standard to retune selected notes, according to the following process: First, a standard note lying on the Western scale is played. Then, a Polyphonic Aftertouch signal is immediately sent to shift the pitch of the standard note to transform it into a non-standard note. The Polyphonic Aftertouch message follows immediately behind the Note On message and pitch value creating the standard note. Thus, the standard note only sounds for about 960 microseconds. The shortest temporal resolution of the human ear is approximately 2-3 milliseconds. As a result, the human ear does not hear the first standard note, since it does not sound for a sufficient length of time. The human ear only perceives the pitch shifted note.