Global microtuning and microtonal notation in MuseScore

Most music software these days is locked in to 12-tone equal temperament. Even if some music software does support microtonality and/or pitch bend to some extent, none of them really support microtonality as intuitively as they could. Pitch bend is usually represented as a deviation from 12-tone equal temperament, and no DAW (with the possible exception of Reaper) allows for piano rolls that are based on a scale other than 12-tone equal temperament.

This brings me to my proposal on how to allow MuseScore to support microtones in the best way possible:

First, there needs to be a special kind of tuning file for MuseScore which maps different configurations of notes and accidentals to their corresponding pitches, and includes a reference pitch. For example, 5-tone equal temperament, with A4 = 440Hz, could be defined as

0 - C
240 - D
480 - E
480 - F
720 - G
960 - A4 (440Hz)
1200 - B
1200 - C
(Note: all accidentals should be able to be represented in this tuning file. For example, the quarter tone sharp accidental could be represented by "t", and the natural three syntonic commas down accidental could be represented by "vvv".)

Second, the actual MIDI notes would have to be derived from this file. For example, to get the MIDI note represented by F6, MuseScore would search for the pitch of the note corresponding to "F" (ignoring the octave), and would find that F4 is 480 cents above C4 while A4, at a constant 440Hz, is 960 cents above C4. (If there was a note with some accidental in the score, such as "Bv", and the same note with the same accidental appeared in the tuning file, MuseScore would be able to detect that and tune the note accordingly.) From this, MuseScore would find that F4 is 480 cents below A4. Finally, MuseScore would find that F6 is two octaves above F4, or 2*1200c above F4. (The custom tuning file should be allowed to define an interval of equivalence other than the octave, so if the second C was given the value 1204 instead, F6 would be 2408 cents above F4 instead of 2400 cents above F4. This would allow for the representation of scales which do not repeat at the octave, such as the Bohlen-Pierce scale). Finally, MuseScore would calculate that F6 is 4.8 semitones below A6, which corresponds to the MIDI note 88 with a pitch bend of +20 cents. The playback of notes with different pitch bend amounts shouldn't be a problem for MuseScore since MuseScore already supports accurate playback of per-note pitch bend, although it would be nice if MuseScore could also support MPE to make this per-note pitch bend more compatible with certain VST plugins.

Note: This MIDI note is only played, not shown on the score. The note shown on the score isn't the MIDI note, but is rather a "wrapper" for the MIDI note to make it appear more intuitive in the context of a microtonal composition. Euwbah's EDO Retuning Plugin ( https://musescore.org/en/project/5-117-edo-retuning-transposing-plugins… ) already does this to an extent, but it only works with specific EDOS (and not equal divisions of a non-octave or unequal scales) and has to be activated every time new notes are added to the score. The dream for me is that the retuning happens automatically and "under-the-hood", which would greatly streamline the process of creating microtonal music.

One big hope I have is that the keyboard shortcuts would align with the tuning defined in the tuning file. The up/down keys would step up/down through the notes listed in the tuning file (skipping over any notes that are the same pitch as the current one), ctrl up/ctrl down would transpose up/down by one interval of equivalence (which, as I said before, should not necessarily be an octave), and J would cycle through all the notes that are mapped to the same pitch in the tuning file. (It might be necessary to implement some kind of priority system, so that a note like Bbb wouldn't get chosen over A when stepping up/down through the notes)

Another hope I have is that this global microtuning will carry over to the piano roll, where the piano isn't just a 12 note per octave piano roll, but rather a piano roll that can support any number of notes per octave. (For tunings with more than 12 notes, this would mean that the piano roll would have to have more than 127 total notes) It would be cool if the notation defined in the tuning file could be represented on the piano roll directly, or perhaps by some alternative like color. Given that MuseScore syncs the notation with the piano roll, it's important that this synchronization continues even with the complexity of having global microtuning in place.

Lastly, there would have to be a way to map MIDI notes coming from MIDI controllers to notes defined in the tuning file, but I don't know exactly how that might work.

To conclude, I am aware that this is a big and complicated feature request that probably won't be implemented in MuseScore for a while (if ever), but I think this specific way of supporting global microtuning is the most intuitive, since it will seamlessly integrate with the notation and the piano roll. I will try my best to answer any questions about this feature request that arise, and I hope that some aspects of this feature request will be considered for a future version of MuseScore. I wish the MuseScore development team good luck in their development of MuseScore 4!