shorten/lengthen left/right stem of beamed eighth

[-Eluze]

in this example there is a collision between th two first notes of both
voices.

<<
  { d''2 }
  \\
  { \stemUp a8 a' s s }
>>

how can i shorten the first stem of the 2nd voice without shortening the 2nd
stem?

i tried lots of items dealing with stems and lengths or how to shorten them:

\override Stem #'(details beamed-lengths) = #'(2)  % from the snippet 
http://lsr.dsi.unimi.it/LSR/Item?u=1&id=681
http://lsr.dsi.unimi.it/LSR/Item?u=1&id=681 

\override Stem #'length-fraction = #0.16
\override Stem #'details #'beamed-lengths = #'(.2)
\override Stem #'beamed-stem-shorten = #'( .1)
\override Stem #'length = #'.16

and i also added

\override Stem  #'no-stem-extend = ##t

but all unsatisfyingly - the best i could get is:

<<
  {d''2}
  \\
  { \stemUp
    \override Stem  #'no-stem-extend = ##t
    \once \override Stem #'length-fraction = #0.16  b8[ a']
  }
>>

but in the next measure i will have a cis'' which will obviously collide
with the beam.

it seems that the stem cannot be forced to stop under the middle (b)
staff-line.

any ideas?



-- 
View this message in context: 
http://old.nabble.com/shorten-lengthen-left-right-stem-of-beamed-eighth-tp30676236p30676236.html
Sent from the Gnu - Lilypond - User mailing list archive at Nabble.com.