Custom tuning and MIDI rendering

For custom tuning in MIDI output, you define both the pitches of the basic scale (c d e f) and the pitch change for each alteration. Both the basic scale and the alteration contribute to the pitch adjustment in the MIDI output.

MIDI implements tuning as a "pitch-bend" adjustment from equal-temperament, changing with every note. Each MIDI channel has its own pitch-bend. You can put each voice on a separate MIDI channel, so each voice can have an independent pitch-bend.

You can use Scheme expressions to generate the pitches and alterations, or you can type the pitches as a list of numbers, in terms of cents or semitones.

Here is an example where you can hear the difference between quarter-comma meantone, 24-tone equal-temperament, etc.