Hi Carlo,
LilyPond prefers to have voices close together but not too close. In
your example, the lower voice avoids a too tight setting on the fourth beat.
But you can position the rests manually with
\override Rest #'staff-position = -4
Meaning, the position on the staff is 4 semitones down from the center
line (i.e. on the lower line). This affects all rests in that voice.
Alternatively you can do it only for one rest:
\once \override Rest #'staff-position = -4
That's how it looks then:
\version "2.18.0"
DrumVoiceOne =
\drummode
{
hh8 hh < hh sn > hh hh hh < hh sn > hh
}
DrumVoiceTwo =
\drummode
{
\override Rest #'staff-position = -4 % this is new
bd4 r8 bd r4 r
}
\score {
<<
\new DrumStaff
<<
\new DrumVoice {
\voiceOne \DrumVoiceOne
}
\new DrumVoice {
\voiceTwo \DrumVoiceTwo
}
>>
>>
}
Cheers,
Joram