Custom Key Signatures Do Not Work Properly

• Jun 16, 2020 - 18:51

When you add a custom key signature, accidentals are in the exact same position on all clefs, meaning that they are actually playing in different keys.

Also, the tool to create custom key signatures is incredibly buggy. When you click on an accidental, it will apply it to a note in the piece you are currently on, not the key signature that you are creating.

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The need to create separate key signatures for each clef is a known limitation indeed, also if you want them transposed - there's really no easy way for MuseScore to know how you'd want the accidentals arranged.

I can confirm an issue where if you click an accidental rather than dragging it, and you have a note selected, it will apply to that note. Feel free to submit on official bug report on this to the issue tracker (see Support menu above). Meanwhile, know that clicking isn't a supported way to use this tool; it requires drag & drop.

In reply to by Marc Sabatella

I agree that custom key signatures present some interesting problems, but, as long as they only have sharps, flats, and naturals, I don't agree that they are too difficult to implement. Moving or transposing the custom key signatures won't be quite as simple as the method for the standard signatures (7 flats through 7 sharps), but even the transposed signatures can be easily calculated. (For some of the custom key signatures, the transpositions may have double sharps or flats.)

The easiest fix is to keep each symbol associated with whichever of the 7 notes it is positioned-on on the treble staff. When a clef change moves C elsewhere, then each symbol in the signature follows its note. For bass clef, each moves down a line or space, and, like the standard signatures, if a sharp, flat, or natural reaches the bottom line or below, it jumps up an octave. Conversely, if using a C clef with C positioned higher than for a treble clef, on reaching the top line or above, a symbol jumps down an octave.

I mention "natural" because Klezmer uses a signature such as Eb,Ab or C#,Bb ("Freygish" scale). The first is often represented as (B-natural),Eb,Ab to make the difference from a standard signature stand out. (The parenthesis indicate that the natural-symbol on the B line would be in parenthesis. Note: I could not find a way to parenthesize a natural using the 3.6 master palette.)

Transposition only takes a little more work. Each of the seven notes has to be transposed independently to build the new signature. To transpose concert Eb,Ab for a Bb instrument, [Ab,B,C,D,Eb,F,G] would become [Bb,C#,D,E,F,G,A] or C#,Bb. For an Eb instrument, [F,G#,A,B,C,D,E] or just G#. More interesting is transposing concert F#,C#,G#,E# [A,B,C#,D,E#,F#,G#] for an Eb instrument, getting F#,C##,G#,D#,A#,E# [F#,G#,A#,B,C##,D#,E#] or its equivalent with flats (again, 7 goes to 5) Bb,Eb,Ab,Gb,Cb [Gb,Ab,Bb,Cb,D,Eb,F]. This doesn't provide courtesy naturals (e.g., the (B-natural) added to Eb,Ab) for "missing" sharps of flats, but the custom key signatures could be checked and, if one exists with the same sharps and flats, then use that signature.

A second problem (or pair of problems), though relatively minor since it affects ease of use and easily can be worked around, deals with the palette menu for key signatures and the "more" button.
1. The more button give an option to create a new key signature. Either it should bring up the master palette with the key signature selected or it should not offer that option. [workaround: ignore it]
2. If the master palette has been used to create non-standard key signatures, the "more" button does not offer those key signatures so they can be added to the palette. [workaround: use them from the master palette]

In reply to by Aaron Grosky

Fwiw, it’s not the math of figuring out the accidentals I was concerned about - that’s trivial indeed. It’s the need to guess which line or space to use for each. You are assuming everyone wants to use the same lines or spaces the standard key signatures use, but my concern is that the people who are experimenting with leaving the world of standard key signatures in first place may well also want to leave the world of standard line/space assignments. So a full solution really requires UI for designing this.

Luckily I think work is progressing towards that already, check the various PR’s submitted recently.

In reply to by Marc Sabatella

I'm glad that work is progressing in that area. For small works (particularly few staves and not too many measures), the current model, though not "sufficient", is still relatively easy to use to create the desired parts. Since I much that I arrange is for big bands, I typically have 9 staves which are transposed and 6 others which use the bass clef. Also, these arrangements have few repeats, so they are usually well over 100 measures. As of yet, I haven't written a big band arrangement with a Freygish (Ukrainian minor) key signature.

Since MuseScore can correctly place the common 1 to 7 sharps or flats, MuseScore should be able to use the same rules to place each of the 7 sharps or flats on staves with a clef other than the treble clef. I'd call these positions the "usual lines and spaces".

Again, for transposition, I'd suggest:
1. Default to using the "usual lines and spaces"*. Count the resulting sharps and flats; a double counting as 2 and in a signature with both sharps and flats, I think the count would be the excess (on sharp and two flats or two sharps and one flat would be a count of 1). If the count is more than 5, follow the current rules for using the "equivalent" signature (e.g., 7 sharps is "equivalent" to 5 flats).
2. Look for a custom version with the same scale. If one, use that no matter the count of sharps and flats. If two and they are equivalent, use the one chosen by the current rules. Otherwise, stay with the default.
3. The user always has the option to override the default choice and choose a different custom signature, but for most, the first two rules should automatically pick the right signature.

  • Note: I got the "usual lines and spaces" wrong in my previous comment since sharps and flats use different usual lines and spaces.

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