Re: voiceOne and oneVoice

[Guy Stalnaker]

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 <lfm@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