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Re: Chords in LilyPond
From: |
Kieren MacMillan |
Subject: |
Re: Chords in LilyPond |
Date: |
Wed, 24 May 2017 18:51:25 -0400 |
Hello Charles,
> I’m participating in the Google Summer of Code working on improving
> LilyPond’s internal representation of chords.
As someone who uses chord names extensively, I’m thrilled that you’re tackling
this!
> The goal here is to create a data structure that will represent a chord’s
> semantics beyond just a list of notes in the chord.
Excellent goal!
> it would be much better to maintain the information provided by the user in
> chord mode about the semantics of the chord through to the naming process.
Agreed.
> Here is a rough list of semantic information I believe should be included in
> the data structure:
> root note
> quality (major, minor, augmented, diminished)
> extension (7, 9, 11, 13, etc.)
> added notes (6, 9, etc.)
> suspensions (sus4, sus2, etc.)
> alterations (flat-5, sharp-9, etc.)
> omitted notes
> added bass note
> inversions
Yes.
> Some things that should be thought about:
> Is the 7 an extension? Or included in the quality the chord? Or maybe
> something else?
Since we’re starting from the ground up, can we not assume triadic harmony for
the input (even if the output makes it look like we do)? For example, <c f bf>
is not really, to my ears, a triadic chord with extensions and suspensions, but
rather a quartic “triad”. Maybe there’s a way to handle this kind of thing (and
others) elegantly?
> How do we deal with semantics that may overlap between these categories? For
> example: is a sharp-5 an alteration or just an augmented chord?
A difficult question. Obviously, it would be great to allow the user — at the
input, throughput, and output stages — to decide how to handle the information.
> polytonal/stacked chords (like Cmaj / Bbmaj)
Yes, please!
> I would love to hear any ideas from the user community about this. And beyond
> the specific issues I’m talking about here, what aspects of LilyPond’s
> support for chords do you believe should be improved or changed?
Here’s one off the top of my head: I would love to be able to easily
input/output something like
C /B /Bb
I’d add more now, but I’ve got to go to see some new opera. =)
> I hope many of you are excited about this conversation.
I sure am! Please feel free to contact me on- or off-list with any questions.
Best,
Kieren.
________________________________
Kieren MacMillan, composer
‣ website: www.kierenmacmillan.info
‣ email: address@hidden