Re: Combining voices in American Hymns

[Rutger Hofman]

On 09/13/2016 11:32 PM, David Wright wrote:
> On Tue 13 Sep 2016 at 21:56:04 (+0100), J Martin Rushton wrote:
> > On 12/09/16 19:21, Karlin High wrote:
> > > 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
> > <snip>

My guess is that \partcombine #'(1 . 9) or \partcombine #'(2 . 9) does 
what you specify. I attach code for default partcombine and both your 
options. Beware that stem crossings need to lead to uncombined notes.

soprano = \relative c''' { b a g f e d c b a g f e }
alto = \relative c'' { c c c c c c c c c c c c }

\score {
    \new Staff <<
        \partcombine
            \soprano
            \alto
    >>
}

\score {
    \new Staff <<
        \partcombine #'(2 . 9)
            \soprano
            \alto
    >>
}

\score {
    \new Staff <<
        \partcombine #'(1 . 9)
            \soprano
            \alto
    >>
}

Rutger Hofman
Amsterdam