lilypond-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Lilypond's internal pitch representation and microtonal notation


From: Joseph Wakeling
Subject: Re: Lilypond's internal pitch representation and microtonal notation
Date: Mon, 20 Sep 2010 16:56:57 +0200
User-agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.12) Gecko/20100915 Lightning/1.0b1 Thunderbird/3.0.8

On 09/20/2010 03:22 PM, Graham Percival wrote:
> Hmm.  This is similar to the distinction between cis and des, correct?

Yes, exactly, it's an enharmonic equivalence.

>  Am I also correct in assuming that d-3/4 is not sufficient?  Also, is
> there a frequency difference between c+1/4 and cis-1/4 ?  Or is this
> purely a difference in graphical notation?

Indeed, d-3/4 is not sufficient [1]: in arrow quarter-tone notation you
want to be able to indicate quarter-tone raising or lowering of any of
the 12 standard tones.

There should be no frequency difference between c+1/4 and cis-1/4.  Some
composers do use the arrow notation to indicate approximate
quarter-tones, but many assume that the quarter-tones are exact.

I did prepare a "cheat" implementation of quarter-tone arrow notation
where there were subtle pitch differences (c+999/4000, cis-999/4000).
This kind of works but it generates all sorts of nightmares with
transposition and means having to write out a HUGE accidentals list (see
discussion in Issue 694).

> I believe that this is a valid feature request -- a single
> "alteration" value is not sufficient to distinguish between c+1/4 and
> cis-1/4.

Yes -- but it goes beyond arrowed quarter-tone notation.  I was a bit
long-winded and abstract because I wanted to stress that it was a
general problem for many different microtonal notations, rather than
just arrow quarter-tones.

> As a general rule -- please take the time to prepare a tiny .ly
> example showing what you wanted to do.  It took me about 10 minutes to
> read your email, think about it, and prepare a good tiny example.
> Since you're more familiar with this material, you probably could have
> made the example in 2-3 minutes.  Having an example makes the
> difference between a developer understanding the issue in a matter of
> 30 seconds vs. 3 minutes, and when we have over 400 open
> bugs+enhancement requests, that difference is significant.

Yes, I'll try and do that in future.

> 2) make a scan of some published music that uses this notation.  This
> will immediately silence anybody who wants to argue (as I somewhat
> did) that a single fraction is sufficient to show any microtonal
> notation.

For arrowed quarter-tones the notation is described (and recommended) in
Kurt Stone's book "Music Notation in the Twentieth Century".  I don't
own a scanner :-( but will try and take a copy of the relevant page
(it's pp.67-70 IIRC; I was looking at it last night).

There are various other notations to consider that have a similar
character.  I'll try and prepare a variety of representative examples.

> 3) send it the bug list so that it gets added to the tracker.
> 
> 4) wait.  Maybe offer a bounty to entice somebody to work on it.

Hans Aberg's work looks promising.  I don't understand it properly yet,
but I'll try and prepare a set of examples to test whether it could
provide a solution.

Best wishes,

    -- Joe

[1] There used to be a "how to do arrow quarter-tone notation" example
somewhere in the docs, which "solved" the problem by simply not having a
cis-1/4 symbol.  That was what got me thinking about the whole issue in
the first place.



reply via email to

[Prev in Thread] Current Thread [Next in Thread]