Updates:
Cc: jan.nieuwenhuizen
Comment #20 on issue 2707 by [email protected]: Patch: Midi volume fixes
http://code.google.com/p/lilypond/issues/detail?id=2707
Jan's Midi changes were supposed to get better dynamics in more complex
cases. If they make it impossible to get reasonable dynamics in simple
cases, they are doing more harm than good. Moving performers to different
levels is a rather typical way of creating per-Staff/per-Voice semantics,
and short of prohibiting <<\\>> altogether, that would seem rather
appropriate for use of implicit parallel voicing.
Perhaps Jan has some other suggestion how to make this piece actually work
under the new system?