Re: Combining voices in American Hymns

[Karlin High]

On 9/7/2016 11:56 PM, David F. wrote:
> Is there a way to combine two voices and print both stems (up and down) when 
> the voices share a note?  \partcombine does not appear to do this by default.
>
> American SATB hymns are typically engraved with the soprano and alto voices 
> combined and the tenor and bass voices combined.  If a note in the soprano 
> voice has the same duration as the note in the alto voice, then the notes for 
> soprano and alto will share a stem.  If the durations are different, then 
> there is no sharing.  And if the notes are the same duration and the same 
> pitch, then the note with have both an up stem and a down stem.

You're not alone with difficulties on American-style part combining. 
Another LilyPond user shared some of her work with me, and I'm still 
studying the approach she uses. Below is a small example I'm using for 
experiments. I'm not very familiar with the inner workings of LilyPond; 
maybe someone will take one look and say, "That will mostly work, but 
you will run into problems with such-and-such situations."
--
Karlin High
Missouri, USA

% BEGIN LILYPOND CODE
\version "2.18.2"

SopranoAltoUpMusic = \relative c {
   <<
     % Soprano notes
     {
       e' f g a b c d e
     }
     % Alto up-stem notes
     {
       c, d e f g s b c
     }
   >>
}

% Alto down-stem notes
AltoDownMusic = \relative c' {
   s s s s s c' s s
}

\score {
   \new Staff = "sopranoalto" <<
     \new Voice = "soprano-alto-up" { \voiceOne \SopranoAltoUpMusic }
     \new Voice = "alto-down" { \voiceTwo \AltoDownMusic }
   >>
}
% END LILYPOND CODE