Just want to follow up on what Lukas-Fabian says here:
====
If you do in-staff polyphony via
<<
{ \upperMusic } \\ { \lowerMusic }
>>
then the \\ makes LilyPond silently add a \voiceOne to \upperMusic and a
\voiceTwo to \lowerMusic, making sure that \upperMusic has upward stems,
articulations etc., and \lowerMusic has everything downwards.
Sometimes it is useful to switch back to "normal" one-voice layout even
in a polyphonic enivoronment; that can be done using \oneVoice.
====
When writing Temporary Polyphonic Context (TPC) in choral music with lyrics
and you need the lyrics to continue *into* the TPC (for example, at a
cadence where sopranos split to two parts and you need stems showing
different voice leading), you use this similar code, but make the voices
explicit and intentionally create a \new Voice. Then the use of \oneVoice
is necessary following the TPC, thus:
%%%%
<<
{ \VoiceOne \upperMusic }
\new Voice {
{
\VoiceTwo \lowerMusic }
}
>> \oneVoice
%%%%
On Wed, Sep 29, 2021, 5:41 PM Lukas-Fabian Moser <l...@gmx.de> wrote:
> Hi Kira,
>
> Am 30.09.21 um 00:32 schrieb Kira Garvie:
> > I realize this is a pretty basic question... but what is the
> > difference between voiceOne and oneVoice? I am writing a multivoice
> > keyboard-style hymn (as opposed to SATB chorale style) and the
> > directions say to switch between oneVoice and voiceOne as needed for
> > stem direction...
> > "(d) Add voiceOne and oneVoice tags throughout to indicate stem
> > direction. If
> > there is no separately stemmed second part at the first note, oneVoice
> > is assumed."
> > Do I need to give an example?
>
> \voiceOne sets the layout for the current voice as if it is the first of
> several simultaneous voices.
> \oneVoice sets the layout for the current voice as if it is an only voice.
>
> If you do in-staff polyphony via
>
> <<
>
> { \upperMusic } \\ { \lowerMusic }
>
> >>
>
> then the \\ makes LilyPond silently add a \voiceOne to \upperMusic and a
> \voiceTwo to \lowerMusic, making sure that \upperMusic has upward stems,
> articulations etc., and \lowerMusic has everything downwards.
>
> Sometimes it is useful to switch back to "normal" one-voice layout even
> in a polyphonic enivoronment; that can be done using \oneVoice.
>
> A typical application is
>
> \once\oneVoice r8
>
> for a single rest that should be centered mid-staff (often, the other
> voice then has a simultaneous skip: s8). But this construction is not
> needed that often anymore because now there is the Merge_rests_engraver
> that is able to collect simultaneous rests in polyphonic situations and
> merge them to a single ("\oneVoice", so to speak) rest.
>
> As a rule, in writing polyphonic music, it's often useful to use
> \voiceOne, \voiceTwo etc. and \oneVoice, and there a comparatively few
> good situations to use an explicit \stemUp or \stemDown.
>
> Is this clear enough without compilable examples?
>
> Lukas
>
>
>
