Re: All Ye People Clap your hands (was Re: lilypond-user Digest, Vol 66, Issue 13)

[Mats Bengtsson]

Francisco, your answer is partially relevant here.

Yes, there's a limitation of 16 channels in MIDI. In LilyPond, each 
Staff and Lyrics context
will result in a new MIDI channel and since channel 0 is reserved for 
common information
and channel 10 is reserved for percussion, there are only 14 left for 
Staff plus Lyrics contexts.
Note that LilyPond automatically will use channel 10 only for 
percussion, so there's no risk
for strange drum sounds unless you really want them.

In this particular .ly file, several unnecessary Lyrics contexts were 
introduced but never used,
which made the problem even worse. The \score block can be simplified into:
\score {
   <<
       \context ChoirStaff <<
       \staffSoprano
       \new Lyrics  \lyricsto "melodySop" \verseone
       \new Lyrics  \lyricsto "melodySop" \versetwo
       \new Lyrics  \lyricsto "melodySop" \versethree

       \staffAlto
       \new Lyrics  \lyricsto "melodyAlt" \verseone
       \new Lyrics  \lyricsto "melodyAlt" \versetwo
       \new Lyrics  \lyricsto "melodyAlt" \versethree

       \staffTenor
       \new Lyrics  \lyricsto "melodyTen" \verseone
       \new Lyrics  \lyricsto "melodyTen" \versetwo
       \new Lyrics  \lyricsto "melodyTen" \versethree
     
       \staffBass
       \new Lyrics  \lyricsto "melodyBas" \verseone
       \new Lyrics  \lyricsto "melodyBas" \versetwo
       \new Lyrics  \lyricsto "melodyBas" \versethree
               >>
       \staffPiano
   >>
 
   \midi {
   }

   \layout  {
     
   }
}


Still, this results in more than 14 used MIDI channels, since the same 
lyrics is repeated below each stave.
One simple workaround is to make separate \score{...} blocks for the 
MIDI and the printed output:
\score{
 ...
\layout{}
}

\score {
   <<
       \context ChoirStaff <<
       \staffSoprano
       \new Lyrics  \lyricsto "melodySop" \verseone
       \new Lyrics  \lyricsto "melodySop" \versetwo
       \new Lyrics  \lyricsto "melodySop" \versethree

       \staffAlto
       \staffTenor
       \staffBass
               >>
       \staffPiano
   >>
 
   \midi {
   }
}

   /Mats

Francisco Vila wrote:
> 2008/5/6 Francisco Vila <address@hidden>:
>   
> >  MIDI files can not have more than 16 channels, that's why your output
> >  gets remapped channels modulo 16 (i.e. starting again from the first
> >  channel). You have too much voices, maybe you could make a specia midi
> >  block that contains only the essential voices for hearing, so their
> >  number do not exceed the maximum allowed.
> >     
>
> Moreover, these warnings are probably harmless if your MIDI sounds
> well, as more than one voice could perfectly sound on a shared channel
> among other one, in modern MIDI players (provided that you want the
> same sound type on both of them)
>
> If you hear some strange drum sounds, this is because your media
> player has a dedicated channel for this, usually #10 or #16.
>
> In this case I don't know what to do from the LilyPond side, except to
> use fewer than 10 channels/voices.
>
>