getting repeats to play in midi

[Tom Cloyd]

I want to have a PDF score with simple repeats, and a midi file in which all repeats are taken. This is revision of a program file which has been working perfectly, except that the midi evidence no repeats. I'm achieving all engraved repeats using the \repeat volta 2{ music} convention.

I'm using Lilypond ver. 2.13.53. Following the Notation Reference section 3.5.4 - "Repeats in MIDI", I have changed the \score blocks in my ly file to read:

\score {
  \context Staff = "guitar" \with {
  \consists "Span_arpeggio_engraver"
  }
  <<
  %\set Staff.instrumentName="Classical Guitar"  %puts name to left of line one
  \set Staff.midiInstrument="acoustic guitar (nylon)"
  \set Staff.connectArpeggios = ##t
  \context Voice = "melody" \melody
  \context Voice = "alto" \alto
  \context Voice = "bass" \bass
  >>

 \layout {
   indent = 0.0\cm % remove indent on first staff
   }
}                                            
\score {
  \unfoldRepeats
  <<
  %\set Staff.instrumentName="Classical Guitar"  %puts name to left of line one
  \set Staff.midiInstrument="acoustic guitar (nylon)"
  \set Staff.connectArpeggios = ##t
  \context Voice = "melody" \melody
  \context Voice = "alto" \alto
  \context Voice = "bass" \bass
  >>
  \midi { %causes generation of midi score\
  }
}

This doesn't work. At the first repeat bar, it sounds like the voices are getting overlaid in some strange way. It is aural nonsense. I've tried a number of alternative placement of the \unfoldRepeats, and none of them have worked.

I don't see what I'm doing wrong, and could use some suggestions, having never before attempted this.

Thanks in advance.