Incorrect Transposition When Switching Instruments Within a Part

• Jan 1, 2022 - 06:46
Reported version
S3 - Major

Revision: 3224f34

How to reproduce:
1. Choose any instrument
2. Use "Instrument change" to switch to an instrument that transposes differently than the current one.
3. Use "Instrument change" to switch back to the original instrument
4. For some instruments this changes the notes, for others the key signature, and others may be either or neither.

Not the end of the world but a big deal since I'm writing stuff that requires different transpositions on the same staff of the same part. I can't find a workaround that doesn't compromise the concert key signature and consequently other parts' key signatures.

I've also found that if you redundantly "Instrument change" to the same instrument, the transposition will transpose the notes and key signature again.

  1. Switch from a C instrument to a Bb instrument on the same staff of the same part. The staff will transpose down a full-step, or C to Bb
  2. From a subsequent measure, "Change instrument" to the same Bb instrument. The staff will transpose down ANOTHER full-step, or Bb to Ab, instead of to Bb as would be correct.

Edit: More Info, attached the file with the original error(38-World_on_Fire-Stick_Figure.mscz), and the workaround file (38-World_on_Fire-Stick_Figure-Bb_Trumpet.mscx).

I attached the demo as I was experimenting with consistently recreating the error and thought that captured the error concisely.

I originally encountered the error in a part for that had several other instruments in the file (electric guitar, electric keyboard, electric bass, voice, Bb trumpet, and melodica). I was attempting to change to melodica within the trumpet part with the "Instrument Change" button under the "Text" palate.
Transposition Error.png
I expected to change to melodica and automatically transpose to concert key, then change back to trumpet and transpose back to Bb. What happened was that changing to melodica does not transpose to concert key, and changing back to trumpet will redundantly transpose the part down another whole-step.

As a workaround, I created a new score with only trumpet (38-World_on_Fire-Stick_Figure-Bb_Trumpet.mscx). Then I used the same "Instrument Change" button under the "Text" palate to switch to melodica and back.
Transposition Workaround.png
I encountered no transposition error in this file. Switching to Melodica resulted in concert key transposition and switching to Bb Trumpet resulted in Bb transposition.

I hope this clarifies things. I will explore the duplicates for more workarounds.


Severity S3 - Major S4 - Minor
Workaround No Yes

I'm not sure I'm understanding the issue but I think you're noticing that in measure 7, the C major key signature is missing from eh staves that require it? I think in general it's likely true that C major key signatures are not always displayed correctly be default in these situations. Workaround is to just add it manually (with Ctrl if you on;y need it for certain staves).

If there is some other aspect to what you are seeing here, please explain in more detail - maybe attach the score as it is before the problem occurs, then give precise steps to reproduce the problem from that point.

Regression No Yes
Workaround Yes No

I see this issue as well, but haven't found a workaround.

  1. Create an orchestra score in the key of C major.
  2. Add instrument B♭ Bass Clarinet, which correctly shows D major (2 sharps) since it's a transposing instrument.
  3. Add a Change Instrument in an empty measure and select B♭ Clarinet.
  4. It adds a key change to E major (four sharps), which is incorrect since B♭ Bass Clarinet and B♭ Clarinet sound the same key.
  5. Add another Change Instrument in a following measure, and return to B♭ Bass Clarinet.
  6. The key will incorrectly switch to F ♯ major (six sharps)!

Here's my version info:
OS: macOS 10.15, Arch.: x86_64, MuseScore version (64-bit):, revision: 3224f34

Severity S4 - Minor S3 - Major
Workaround No Yes

The problem only seems to occur if I use the Change Instrument text from the text pallet. It works OK for if I add an instrument change from the [Add]>[Text] menu which is a workaround.

I note that the "Current instrument" field in the "Select Instrument" dialogue is empty when I add the pallet text. If I add it from the [Add]>[Text] menu and then click on select instrument in the Inspector, the original instrument is shown in the "Current Instrument" field. It seems that adding a pallet text is not detecting the current instrument and that would explain the symptoms you are experiencing.

I have upped the severity to Major as it seems the pallet item "Change Instr." is broken and can't be used for transposing instruments.