Jonathan Kulp wrote Thursday, August 14, 2008 5:50 AM
I had a similar problem with an example I was working on for GDP
Rhythms, in Notation Reference 1.2.6.2. If you look at that example,
you can see that there's a whole series of 8ths that ought to be
autobeamed but are not. I couldn't even make them beam properly
manually. I ended up sidestepping the issue and removing the extra
voice, since that example is only meant to show how to make another part
in a different staff begin at the right place after a cadenza. I don't
know why the author of it introduced the complexity of multiple voices
in that context.
Regarding your example, there were two ways I could get it to beam those
last two 8ths automatically. One was to move the C in the final chord of
the bar to the upper voice and allow the multiple-voice passage to last
for the entire bar, rather than for only the first three beats. Here:
\version "2.11.55"
\relative { \clef bass << {e8 d d c d8 c c4 } \\ { <c g>4 g <b f>4 <f
a> } >> }
This makes the beaming work, and all the notes are the same, but it does
not preserve the original intent of having the final chord <f a c> all
in the lower voice. I'm sure you found that you could manually beam
the "d8[ c]" but it doesn't seem like you should have to.
The other way was to leave the <f a c> chord intact in the lower voice,
but put it inside the multi-voice << >> and add a quarter-note skip to
the upper voice:
\version "2.11.55"
\relative { \clef bass << {e8 d d c d8 c s4 } \\ { <c g>4 g <b f>4 <f a
c> } >> }
This does seem like a workaround, though, as it looks like something
that ought to work exactly the way you had it the first time. Anyone
else see what the problem could be?
I think the problem is this. The autobeaming rules define
where beams should start and end, but mainly where they
should end. The rules are defined in scm/auto-beam.scm
and are applied in a Voice context. In common time, eighth
note beams end only on half-note boundaries. Autobeaming
only kicks in when one of the defined end-points is reached,
and in these examples the voice is terminated before the
next half-note boundary is reached. The common feature in
the 'workarounds' is to add notes or spacers so that one
of the defined beam end-points is reached before the voice
terminates.
This seems to be a drawback of inserting short parallel
voices which probably merits a mention in the docs (that's
why I'm answering, Graham :)
I would use your first solution, Jonathan, and simply
insert a \stemDown:
\relative c' {
\clef bass
<<
{ e8 d d c d8 c \stemDown <f,, a c>4 }
\\
{ <c' g>4 g <b f>4 }
>>
}
Trevor
Best,
Jonathan
James E. Bailey wrote:
I don't understand this. Why aren't the last two eighth notes beamed
together?
\version "2.11.54"
\relative { \clef bass << {e8 d d c d8 c } \\ { <c g>4 g <b f>4} >> <f
a c> }
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Jonathan Kulp
http://www.jonathankulp.com
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