Hello M.G.,

Your "repro" steps are a model for what a developer loves to get from a user having trouble! Now I know exactly what the problem is, and it only took me a few minutes to understand why, given your excellent report.

The problem is that original piano RH track was assigned to "Auto" channel, but there were no MIDI channels available for it to play on. All of the other tracks were assigned to all 16 of the MIDI channels 1 to 16. During playback, MidiNotate will assign an auto-channel track to any non-used MIDI channel, but will not attempt to assign that auto-channel track to any channel number that is specifically designated for another track. Since all 16 channels were specifically assigned to other tracks, there were no channels left for the piano RH auto-channel track.

This problem was easy to fix, though. I just assigned all of the tracks to "Auto" channel, except for the percussion track, which should be assigned to channel 10. That's a General MIDI (GM) requirement, that GM drums must be performed on channel 10. In order to assign all of the track, except the drum track, to Auto channel, go to the Track Setup, click the heading for "Channel". That brings up the Assign Channel to All Tracks dialog box. Choose the option "Use automatic channel assignments during playback.".

I see that there is a usability problem here. Maybe I'll have MidiNotate display a non-obtrusive message in the status bar at the bottom of the window that says, "No channels left for Auto-channel", or something like that.

MidiNotate's Auto-channel feature allows you to assign more than 16 tracks with distinct sounds for a given MIDI device, as long as no more than 16 are playing at a time.

In your particular case, you don't really need to use Auto channel. As you discovered, you could change the assignment of the piano RH track to channel 1, because it shares the same GM Grand Piano sound as the second track for piano LH.

Why did the piano RH track get assigned to Auto-channel in the first place? That's what MidiNotate Composer does by default.

Cheers
-- Mark