Re: Map voices to channels in MIDI output

[Keith OHara]

Neil Puttock <n.puttock <at> gmail.com> writes:
> On 9 March 2011 00:09, Keith OHara <k-ohara5a5a <at> oco.net> wrote:
> 
> > In 2.13.53, I cannot find a way to make midiInstrument have effect.
> 
> Can you post a snippet showing the problem?

Let's use the manual example I linked earlier, but give names to the Voice 
contexts.  Obviously this needs further re-arrangement now that midi channels 
go with the Voice, but I can't see a way to arrange it so it does work.

\score {
  <<
    \new Staff {
      \key g \major
      \time 2/2
      \set Staff.midiInstrument = #"flute"
      \set Staff.midiMinimumVolume = #0.7
      \set Staff.midiMaximumVolume = #0.9
      \new Voice = "flauto" \relative c''' {
        r2 g\mp g fis~
        fis4 g8 fis e2~
        e4 d8 cis d2
      }
    }
    \new Staff {
      \key g \major
      \set Staff.midiInstrument = #"clarinet"
      \set Staff.midiMinimumVolume = #0.3
      \set Staff.midiMaximumVolume = #0.6
      \new Voice = "clarinetto" \relative c'' {
        b1\p a2. b8 a
        g2. fis8 e
        fis2 r
      }
    }
%{%}>>
  \layout {}
  \midi {
    \context {
      \Score
      tempoWholesPerMinute = #(ly:make-moment 72 2)
    }
  }
}

The program change commands that set the midiInstrument go to channel 0. The 
\xC049 below sets channel 0 to flute, then the other track has x\C047 trying to 
set the same channel to clarinet.

0000030: 6f72 3a20 00ff 011e 474e 5520 4c69 6c79  or: ....GNU Lily
0000040: 506f 6e64 2032 2e31 332e 3534 2020 2020  Pond 2.13.54    
0000050: 2020 2020 2020 00ff 5804 0201 1208 00ff        ..X.......
0000060: 5103 065b 9a00 ff2f 004d 5472 6b00 0000  Q..[.../.MTrk...
0000070: 7000 ff03 0000 c049 00ff 0405 666c 7574  p......I....flut