Re: Polyrhythmic music

[Paul Hodges]

Thanks a lot, that's brilliant!

After writing to the list, I found the short example of polymetric notation (using the right keywords really helps - polyrhythmic finds so little!), and I think I can use that to solve most of the problems I can see.  Certainly the bit in the middle of the second line of the example I posted.  There are places elsewhere with non-aligned bar signatures and bar lines; and also with notation of different values in the two staves, combined with feathered beams, which \scaleDurations and \featherDurations should solve.

Your code for changing the staff lines I'd already worked out, but I was a bit stuck on the beam arrow - I'm hopeful that I'll be able to manage enough Scheme to extend your procedure for that to make a more exact match to the MS (i.e. with the arrow on a beam extension). Seeing how you handled enabling and disabling the cross-system bar lines is helpful, and the markup for the arrow indicating when notes are played together.  I already have (from my previous project) the code to add a stroke to the multiple grace notes.

Thanks again for taking the time to do that much.

Paul

From: Jean Abou Samra <jean@abou-samra.fr>
To: Paul Hodges <pwh@cassland.org>, <lilypond-user@gnu.org>
Sent: 27/10/2022 13:03
Subject: Re: Polyrhythmic music

Le 27/10/2022 à 12:10, Paul Hodges a écrit :
> This is not (yet) a specific query, I'm afraid.  My new project is
> going to push my usage of LilyPond way beyond what I've done up till
> now.  I have already found solutions for a couple of new challenges,
> and a partial solution to a third.
>
> But my main issue is polyrhythms.  There are two instruments, and some
> of the time they play in sync, with the same barring, and barlines
> which join across the system; then at other times they separate, and
> may play a section at different speeds and barring, coming together
> again later.  I know that I have to move the Timing_translator
> engraver from Score context to Staff, but so far my searching has not
> shown me how to work further with this.  How, for instance, do I
> indicate the points at which the parts meet (within a polyrhythmic
> section), and how to change between synchronised and polyrhythmic
> sections?
>
> Does anyone have any hints, guidance, or experience which might help
> get me started?  I have attached a bad scan of a couple of lines of
> the MS to give an idea of what I'm facing.



For a start, have a look at the documentation:

https://lilypond.org/doc/v2.22/Documentation/notation/displaying-rhythms#polymetric-notation

Several techniques related to polyrhythms are explained there with
examples, including moving Timing_translator and using \scaleDurations.

From the image you sent, I actually don't understand where the
polyrhythms are, can you elaborate?

See attached for .ly code for the beginning of your excerpt (it gave me
some busywork to relax…). As you can see, there are unsurprisingly lots
of tweaks. I hope this gets you started for the rest.

Best,
Jean