Re: Lilypond's internal pitch representation and microtonal notation

[Hans Aberg]

On 21 Sep 2010, at 14:16, Carl Sorensen wrote:

> It seems to me that the pitches natural+1/4 and sharp - 1/4 are the  
> same
> pitch (i.e. enharmonic equivalents) and that it is appropriate to have
> either one represent the same pitch.

Arab music uses E24 quarter-tone accidentals, though the actual tuning  
may be different. For example, in E53 use m = 4, M = 9 (Pythagorean  
tuning), and n = 6 (same as one Persian interpretation). Then one gets  
an accidental "+" equal to n-m = 2 and another "-" which is n-M = -3.  
The sharp # is M-m = 5. So here the accidental "+" is the same as a #  
+ "-".

One may also use accidentals for m-n = -2 and M-n = 3. Then "+" is  
different from # + (m-n) = 3. This happens in Turkish music, though  
they use n = 5.