Re: beaming problem

[Simon Albrecht]

Hello,

Am 29.05.2015 um 11:42 schrieb Haipeng Hu:
> Hello,
>    I'm now composing an orchestral work, in which there are plenty of
> meter changes such as 5/4 and 6/4. Since I'm blind,
It’s so impressive that you are able to do this – write lilypond code, 
read scm files etc. – without eyesight. Kudos!
>   I gave part of it
> to a teacher, and he told me that the beaming in 5/4 and 6/4 is
> incorrect. He told me the beaming must be clear for performance, so
> 5/4 must be 3/4+2/4, and 6/4 3+3. So, please look at the two pictures
> in zipped attachment.
No attachment there…
>   The one was directly from Lilypond, and the
> other from Sibelius, in which I imported the midi file. The beaming in
> Sibelius is correct, while in Lilypond, all 16th notes are grouped as
> 4th. I checked the time-signature-setting.scm, and found the setting
> for 6/4 is wrong. Although the comment says for 32nd notes, the line
> below it still groups 16ths as 4ths. Is this a mistake? Could anyone
> check the theory book for beaming rules and correct the scm file?
I believe that Lily’s current behaviour is carefully designed and will 
comply with the relevant literature. If in 6/4 time 16th notes would be 
beamed by half bars, the very long groups of 12 notes would be very 
difficult to read, except if you use subdivision:

%%%%%%%%%%%%%%%%%%%%%%%%%
\version "2.19.20"

\score {
  {
    \set subdivideBeams = ##t
    \time 6/4
    \set Timing.beamExceptions = #'()
    \repeat unfold 24 c'16
  }
}
%%%%%%%%%%%%%%%%%%%%%%%%%%

See also 
<http://lilypond.org/doc/v2.18/Documentation/notation/beams#setting-automatic-beam-behavior> 
for more information on using baseMoment, beatStructure, and beamExceptions.

HTH, Simon