\score {
  \new Staff <<
    \new Voice {
      \set midiInstrument = #"flute"
      \voiceOne
      c' d' e' c'
      e' f' g' g'
    }
    \new Voice {
      \set midiInstrument = #"clarinet"
      \voiceTwo
      r1
      c'4 d' e' c'
    }
  >>
  \layout { }
  \midi {
    \context {
      \Staff
      \remove "Staff_performer"
    }
    \context {
      \Voice
      \consists "Staff_performer"
    }
    \tempo 2 = 72
  }
}