[sdiy] MIDI, note off or note on with zero velocity?

[Colin f]

On 13 January 2013 14:28, Richard Wentk <richard at wentk.com> wrote:
> If your sequencer sends two notes pn the same pitch with the same channel
- which can happen - sending two note offs will kill both.

I would avoid supporting stacking of duplicate notes on a receiver.
The behaviour is not defined in the MIDI spec, and there instruments which
don't like it.
The Yamaha TX802, for example, will assign an additional voice for a
duplicated note-on.
The first note-off will gate-off the first assigned voice, but then it
thinks that note is off, so further matching note-offs are ignored, leaving
a hanging note.
Any synth might receive a single bit error in a note number which could
cause a wrong note to be played. If that note has also been sent correctly
you'd have a situation where the synth thinks a note has been played twice,
but it's never going to receive a second note off. Playing and releasing the
hanging note on the master keyboard won't clear it, since the new note-on
would be stacked.
I'd say best practice is for a note-off to end that note on any voice on
that channel/note combination.

Cheers,
Colin f