Re: Microtonal accidentals

[Hans Aberg]

On 3 Nov 2013, at 11:42, Joseph Rushton Wakeling <address@hidden> wrote:

> On 03/11/13 11:20, Hans Aberg wrote:
>> FYI, some "Extended Helmholtz-Ellis JI” accidentals [1-2], in fact designed 
>> quite recently, but a nice input. There is also a Unicode font at [3]. 
>> Notation also mentioned at [4].
>> 
>> The arrow accidentals that LilyPond has, are used for syntonic comma 81/81 
>> alterations (staff system in Pythagorean tuning). LilyPond does not have 
>> those for double sharps and double flats. In addition, there are accidentals 
>> with double arrows, for double syntonic comma alterations, which LilyPond 
>> does not have. (And even triple arrows.)
>> 
>> Some traditional quartertone accidentals end up on the 11-limit rational 
>> interval 33/32, which seems to be a good idea: in E72, it is approximated 
>> with E24 quartertones.
>> 
>> 1. http://www.newmusicbox.org/assets/72/HelmholtzEllisLegend.pdf
>> 2. http://www.marcsabat.com/pdfs/notation.pdf
>> 3. http://www.marcsabat.com/
>> 4. https://en.wikipedia.org/wiki/Just_intonation
> 
> Interesting references, thank you!
> 
> It's worth bearing in mind that those symbols are far from absolute in their 
> meaning -- different composers have used them to indicate different things.

Yes, LilyPond just provides the glyphs.

> For Lilypond in particular, the problem of supporting microtonal notation is 
> less about symbols per se ...

It used to be problem to just take a glyph from an arbitrary font and use it in 
LilyPond. In addition, LilyPond might want to have glyphs that are better 
designed for us in a staff.

> ...and more about the underlying representation of pitch, and how that 
> relates both to accidentals and transposition.

I know how to do it from the theoretical point of view, but somebody who knows 
the internals of LilyPond must do it.

> Short version: in many microtonal notations, the number of enharmonic pitches 
> is expanded -- but Lilypond has no way to represent these enharmonics.

The staff notation system itself cannot express enharmonic equivalents, so just 
in the case of E12, it has to be expressed at the end of the typesetting 
process.