lilypond-learning: Explicitly instantiating voices
3.2.2 Explicitly instantiating voices
-------------------------------------
Voice contexts can also be created manually inside a ‘<< >>’ block to
create polyphonic music, using ‘\voiceOne’ ... ‘\voiceFour’ to indicate
the required directions of stems, slurs, etc. In longer scores this
method is clearer, as it permits the voices to be separated and to be
given more descriptive names.
Specifically, the construct ‘<< \\ >>’ which we used in the previous
section:
\new Staff {
\relative c' {
<< { e4 f g a } \\ { c,4 d e f } >>
}
}
is equivalent to
\new Staff <<
\new Voice = "1" { \voiceOne \relative c' { e4 f g a } }
\new Voice = "2" { \voiceTwo \relative c' { c4 d e f } }
>>
Both of the above would produce
[image src="" alt="[image of music]" text="image of music" ]
The ‘\voiceXXX’ commands set the direction of stems, slurs, ties,
articulations, text annotations, augmentation dots of dotted notes, and
fingerings. ‘\voiceOne’ and ‘\voiceThree’ make these objects point
upwards, while ‘\voiceTwo’ and ‘\voiceFour’ make them point downwards.
These commands also generate a horizontal shift for each voice when this
is required to avoid clashes of note heads. The command ‘\oneVoice’
reverts the settings back to the normal values for a single voice.
Let us see in some simple examples exactly what effect ‘\oneVoice’,
‘\voiceOne’ and ‘voiceTwo’ have on markup, ties, slurs, and dynamics:
\relative c' {
% Default behavior or behavior after \oneVoice
c4 d8~ d e4( f | g4 a) b-> c |
}
[image src="" alt="[image of music]" text="image of music" ]
\relative c' {
\voiceOne
c4 d8~ d e4( f | g4 a) b-> c |
\oneVoice
c,4 d8~ d e4( f | g4 a) b-> c |
}
[image src="" alt="[image of music]" text="image of music" ]
\relative c' {
\voiceTwo
c4 d8~ d e4( f | g4 a) b-> c |
\oneVoice
c,4 d8~ d e4( f | g4 a) b-> c |
}
[image src="" alt="[image of music]" text="image of music" ]
Now let’s look at three different ways to notate the same passage of
polyphonic music, each of which is advantageous in different
circumstances, using the example from the previous section.
An expression that appears directly inside a ‘<< >>’ belongs to the
main voice (but, note, *not* in a ‘<< \\ >>’ construct). This is useful
when extra voices appear while the main voice is playing. Here is a
more correct rendition of our example. The red diamond-shaped notes
demonstrate that the main melody is now in a single voice context,
permitting a phrasing slur to be drawn over them.
\new Staff \relative c' {
\voiceOneStyle
% This section is homophonic
c16^( d e f
% Start simultaneous section of three voices
<<
% Continue the main voice in parallel
{ g4 f e | d2 e) | }
% Initiate second voice
\new Voice {
% Set stems, etc., down
\voiceTwo
r8 e4 d c8~ | c8 b16 a b8 g~ g2 |
}
% Initiate third voice
\new Voice {
% Set stems, etc, up
\voiceThree
s2. | s4 b c2 |
}
>>
}
[image src="" alt="[image of music]" text="image of music" ]
More deeply nested polyphony constructs are possible, and if a voice
appears only briefly this might be a more natural way to typeset the
music:
\new Staff \relative c' {
c16^( d e f
<<
{ g4 f e | d2 e) | }
\new Voice {
\voiceTwo
r8 e4 d c8~ |
<<
{ c8 b16 a b8 g~ g2 | }
\new Voice {
\voiceThree
s4 b c2 |
}
>>
}
>>
}
[image src="" alt="[image of music]" text="image of music" ]
This method of nesting new voices briefly is useful when only small
sections of the music are polyphonic, but when the whole staff is
largely polyphonic it can be clearer to use multiple voices throughout,
using spacing notes to step over sections where the voice is silent, as
here:
\new Staff \relative c' <<
% Initiate first voice
\new Voice {
\voiceOne
c16^( d e f g4 f e | d2 e) |
}
% Initiate second voice
\new Voice {
% Set stems, etc, down
\voiceTwo
s4 r8 e4 d c8~ | c8 b16 a b8 g~ g2 |
}
% Initiate third voice
\new Voice {
% Set stems, etc, up
\voiceThree
s1 | s4 b c2 |
}
>>
[image src="" alt="[image of music]" text="image of music" ]
Note columns
............
Closely spaced notes in a chord, or notes occurring at the same time in
different voices, are arranged in two, occasionally more, columns to
prevent the note heads overlapping. These are called note columns.
There are separate columns for each voice, and the currently specified
voice-dependent shift is applied to the note column if there would
otherwise be a collision. This can be seen in the example above. In
bar 2 the C in voice two is shifted to the right relative to the D in
voice one, and in the final chord the C in voice three is also shifted
to the right relative to the other notes.
The ‘\shiftOn’, ‘\shiftOnn’, ‘\shiftOnnn’, and ‘\shiftOff’ commands
specify the degree to which notes and chords of the voice should be
shifted if a collision would otherwise occur. By default, the outer
voices (normally voices one and two) have ‘\shiftOff’ specified, while
the inner voices (three and four) have ‘\shiftOn’ specified. When a
shift is applied, voices one and three are shifted to the right and
voices two and four to the left.
‘\shiftOnn’ and ‘\shiftOnnn’ define further shift levels which may be
specified temporarily to resolve collisions in complex situations – see
Real music example.
A note column can contain just one note (or chord) from a voice with
stems up and one note (or chord) from a voice with stems down. If notes
from two voices which have their stems in the same direction are placed
at the same position and both voices have no shift or the same shift
specified, the error message “Too many clashing note columns” will be
produced.
See also
........
Learning Manual: Moving objects.
Notation Reference: (lilypond-notation)Multiple voices.
Info Catalog
lilypond-learning: I'm hearing Voices
lilypond-learning: Voices contain music
lilypond-learning: Voices and vocals