\layout { \context { \Staff \accepts "VoiceBox" } \context { \name "VoiceBox" \type "Engraver_group" \defaultchild "Voice" \accepts "Voice" \accepts "NullVoice" } } customPartCombineUp = #(define-music-function (partOne partTwo) (ly:music? ly:music?) "Take the music in @var{partOne} and @var{partTwo} and return a @code{VoiceBox} named @q{Up} containing @code{Voice}s that contain @var{partOne} and @var{partTwo} merged into one voice where feasible. This variant sets the default voicing in the output to use upward stems." #{ \new VoiceBox = "Up" << \context Voice = "one" { \voiceOne } \context Voice = "two" { \voiceThree } \context Voice = "shared" { \voiceOne } \context Voice = "solo" { \voiceOne } \context NullVoice = "null" {} \partCombine #partOne #partTwo >> #}) customPartCombineDown = # (define-music-function (partOne partTwo) (ly:music? ly:music?) "Take the music in @var{partOne} and @var{partTwo} and return a @code{VoiceBox} named @q{Down} containing @code{Voice}s that contain @var{partOne} and @var{partTwo} merged into one voice where feasible. This variant sets the default voicing in the output to use downward stems." #{ \new VoiceBox = "Down" << \set VoiceBox.soloText = #"Solo III" \set VoiceBox.soloIIText = #"Solo IV" \context Voice ="one" { \voiceFour } \context Voice ="two" { \voiceTwo } \context Voice ="shared" { \voiceFour } \context Voice ="solo" { \voiceFour } \context NullVoice = "null" {} \partCombine #partOne #partTwo >> #}) soprano = { d'4 | cis' b e' d'8 cis' | cis'2 b } alto = { fis4 | e8 fis gis ais b4 b | b ais fis2 } tenor = { a8 b | cis' dis' e'4 b8 cis' d'4 | gis cis' dis'2 } bass = { fis8 gis | a4 gis g fis | eis fis b,2 } \new Staff << \key b\minor \clef alto \partial 4 \transpose b b' \customPartCombineUp \soprano \alto \customPartCombineDown \tenor \bass >>