MusicXML import still ignores quarter-tone accidentals in OpenMusic 8.0

[takuyaimahori50]

Dear Karim and OpenMusic developers,

I would like to report a MusicXML import issue which I have confirmed in both OpenMusic 7.7 and OpenMusic 8.0 with MacOS 26.5 on MacBook Pro 2025 with M4.
secondasinfonia20260604-52.musicxml (161.6 KB)

I updated to OpenMusic 8.0, released on March 30, 2026, and tested the same MusicXML file again. Unfortunately, the issue remains unchanged.

The MusicXML file was exported from Sibelius and contains quarter-tone accidentals. When imported into OpenMusic as a poly/voice object, the pitches are rounded to semitone values.

I checked the MusicXML file directly. The quarter-tone information is present in the file, but it appears in the element rather than in the element. For example:

C 0 5 quarter-sharp

and:

A 1 4 three-quarters-sharp

In OpenMusic, these notes are imported respectively as C natural and A sharp, without the additional 50-cent offset.

It seems that the MusicXML importer reads the value but does not take microtonal values such as quarter-sharp and three-quarters-sharp into account.

Expected behavior:
OpenMusic should preserve quarter-tone accidentals from MusicXML, for example:

• quarter-sharp: +50 cents relative to natural
• three-quarters-sharp: +50 cents relative to sharp
• quarter-flat: -50 cents relative to natural
• three-quarters-flat: -50 cents relative to flat

Actual behavior:
The imported poly/voice object contains pitches rounded to semitone values.

I also previously reported an issue concerning ties in MusicXML import. Since OM 8.0 was released on March 30, I assume that this previous report has probably not yet been reflected in the current release.

I attach a relevant MusicXML file exported from Sibelius. Please let me know if a smaller minimal test file would be more useful.

Best regards,

Takuya Imahori

[haddad]

Dear Takuya,

First of all, if you need debugging, you should rely on a MWE example and not a “monster” example. Please next time be sure to forward a simple (in this case one measure, one instrument) example in a way to make an easy debugging.

But anyhow, i have run the test and the problem is not in the om import issue but in Sibelius export one. Explanation:

Musicxml mixes content and appearance, meaning the real notes and how they must appear. In some cases as this, you can have a c natural appearing as a c quarter sharp but still plays a c natural.

An example from your file:

<pitch>
     <step>B</step>
     <alter>0</alter>
     <octave>3</octave>
    </pitch>
    <duration>21</duration>
    <tie type="start" />
    <instrument id="P38-I1" />
    <voice>1</voice>
    <type>32nd</type>
    <accidental>quarter-sharp</accidental>
    
    

Here a B natural notated as b quarter sharp. But still in reality it is a B natural. If you need the imported REAL note to be a B quarter sharp it should export as:

    <pitch>
     <step>B</step>
     <alter>0.5</alter>
     <octave>3</octave>
    </pitch>
    <duration>21</duration>
    <tie type="start" />
    <instrument id="P38-I1" />
    <voice>1</voice>
    <type>32nd</type>
    <accidental>quarter-sharp</accidental>

The REAL alteration is between the tag. The appearance is in the tag.

So maybe just try first in Sibelius a simple one measure such as:

and try to tell Sibelius that your example is really in quarter notes. As you exported, Sibelius just considers the notes as in a 1/2 tone (12 EDO) scale but with modified alterations. And that makes them import as 1/2 tone scale.

I don’t know about Sibelius, but you should have something to set your score in a given temperament or EDO. Please consult their documentation.

I run a test using MuseScore with the MWE example above and the import in OM is correct.

Best
K

[takuyaimahori50]

Dear Karim,
sorry, I upload now a simple example.
This is the MusicXML file created by Sibelius with quarter tones. I attach also the screen shot.
The poly of OpenMusic imports it, and does not understand the microtonals, even I set 48 EDO.
This is the accual situation… Could you check it?
Takuya

accidentaltest01.musicxml (5.4 KB)

[haddad]

Thanks Takuya,

I will see what I can do and will get back to you ASAP

Best
K

[haddad]

Are you using the latest Sibelius version?

[takuyaimahori50]

Dear Karim,
yes, I use the latest version of Sibelius 2026.5.
Takuya

[haddad]

Dear Takuya,

Can you try this patch:
xml-import-accidentals.lisp (2.2 KB)

(put it in the init folder of your OM app)

Tell me if it works for you.

Best
K

[takuyaimahori50]

You mean “show the contents of the package” of OM8.0.app? I did it and found the init folder, then I put your lisp. Now the poly impots correctly the xml file created by Sibelius. Thank you!!