Resolved Is there a channel mute message, and if so is it sysex or a CC?

No, no channel mute as such but just turn CC#7 down to zero.

Hello John thanks for your answer, setting the volume to zero does it still take up the voice "effect the multitimbrality?".
Why not discard any note at midi channel "filter"? It does not seem more computing intensive?

Hmm! Interesting question.

I can't give a definitive answer, but ...

If we're just talking about a MIDI file player without a track/channel mute control, then I suppose, as the Note On mesages will still be arriving at the sound module, one would expect them to be played, just at zero volume. So, I suppose they would take up timbrality.

If I don't want a channel played at all on a MIDI file I just make a copy with the appropriate data deleted completely.
Very easily done in seconds with most sequencing software.

The routing of channels to parts is defined with the RX. CHANNEL patch parameters; see p. 36 of the manual. To prevent any messages on a channel from being received, set the corresponding part to OFF.

Clemens Thanks i will try to do that.