Midi equalisation

[Hilary Snaden]

This (trimmed) example doesn't work as the documentation suggests it
should, in this case to reduce the volume of the organ relative to the
voices. Changing the volume values makes no difference at all. \dyns
contains dynamics for the organ, each voice part has its own dynamics.
Am I missing something?

\score {
  <<
    \new Staff = "v1" {
      \set Staff.midiInstrument = #"choir aahs"
      \set Staff.midiMaximumVolume = #0.8
      \set Staff.midiMinimumVolume = #0.4
      \new Voice { \transpose d f \musicsoprano }
    }
    \new Staff = "v5" {
      \set Staff.midiInstrument = #"church organ"
      \set Staff.midiMaximumVolume = #0.4
      \set Staff.midiMinimumVolume = #0.2
      \new Voice { \transpose d f \upper }
    }
    \new Voice = "v7" { \dyns }
    \new Voice = "tempi" {
      \tempo 4.=84
    }
  >>
  \midi { }
}

-- 
Hilary