Problems with writing Arabic Maqamat

Hi guys,
I’m trying to add a costume tonality system of a nonwestern scale (Rast) of which the E should be quarter-tone flat but I’m having playback issues.

I’ve created a new tonality system, added the quarter-tone accidental with 0/24 divisions and a costume key signature of E quarter-tone flat. But when I turned the playback on it was playing a natural E instead of E quarter-tone flat.

I’ve managed to bypass it through the EDO-24 and write “Atonal” but then I have to click the quarter-tone accidental every bar and can write the key signature (E quarter-tone flat) only after I write the whole piece to make the playback work properly.

Will appreciate your help.


If you specify an accidental with a delta of 0/24 divisions, it won’t change the pitch of the note at all. If you want the new flat accidental to be a quarter-tone flat, it should have a delta of -1/24 divisions.

Ohh I missed that step but now I see it’s written in the Dorico help under “Edit accidental dialog”.

Thank you!


Curious to know this about the pitch delta and its uses:

I’m now using Persian Accidentals, which is in 12 divisions. I successfully customized a key signature but now I’m trying to get the playback to sound right. I understand that to achieve this, I need to manipulate the pitch delta of each customized accidental.

I am now using three accidentals, and I cannot seem to get the right playback pitch.

  1. Regular flat symbol (half tone down)
  2. Quarter-tone flat (quarter tone down)
  3. Regular sharp symbol (half tone up).

Given that I’m using a system that has 12 divisions, how does the pitch delta work? I haven’t been able to successful find the information in the manuals/tutorials.

Many thanks in advance!

when you need quarter tones, why do you work in a 12 division system?
I guess you will need a 24 division system to start with.

Dorico has a predefined 24-division tonality system.

You have input a key signature first. Select “Equal temperament (24 EDO)” in the right hand panel, then press K and enter a key signature (or type atonal in the popover if you don’t want a key).

Then you can select accidentals from the right hand panel when you enter the notes.

If you want to change the symbols for your Persian accidentals, or define short cuts for the quarter tones accidentals, edit the tonality system. It should be fairly obvious how things are defined. A semitone is two divisions and a whole tone is four.

Hi Estigy,

Thanks for the tip. I guess I wrongly assumed that using some of the accidental systems that came with Dorico to also put into account the correct division system needed. I thought that it was just a matter of tweaking the pitch delta with these systems to get the right playback.

Thanks again.

Hi Rob,

Many thanks for your help. I realize I wrongly assumed that selecting the pre-loaded symbols under a named system does not automatically mean that they are fully prepared for usage without some tweaking.

Thanks again,