Instrument change does not adjust key signature for new instrument

• Dec 13, 2019 - 09:59
Reported version
S3 - Major

I have a part that starts with Bb Clarinet and switches to Alto Sax in a big band chart. The key signature starts out for the Clarinet but when I change instrument to the Alto Sax the key signature in the part stays the same, ie it doesn't adjust to the written key signature for the new instrument.
If I try to change key signature in the part at that point it changes the key for the whole chart (all the parts).
I can't find a way of working around the wrong key.
Switching instruments like this is a common feature in big band charts especially for the sax section.

Attachment Size
Blue_Skies.mscz 139.26 KB


This seems to be "by design". Whether the design is right is another matter. Anyway, inserting an instrument change only updates the transposition from that point on. Adjusting the key signature has to be done manually. So, hold CTRL (or CMD for a MAC) while you drag the desired (concert pitch) key signature onto the first note or rest after the change. If you don't hold CTRL you will get the key signature on all the staves. This is described in the handbook…

I can sort of see why the design works this way. You don't always want a new key signature after an instrument change. I have seen this in a few 20th Century and later orchestral clarinet parts where a change from Bb to A doesn't have a key signature change; instead, the new transposition is effected using accidentals. It always causes me a bit of concern when I come across it. I wonder if the publisher missed something. It usually takes a bit of checking with the bassoonist sitting next to me to confirm that no, there is no key change there and yes, my new transposition is correct. Of course it sometimes happens that an instrument change occurs at a key change for the whole orchestra and sometimes this means the new key signature with the new instrument is the same as the key signature with the old instrument. Even in those cases, I would prefer to see a repeat key signature as I can hear the key change but can't see anything in my part to indicate it.

Perhaps the default ought to be to automatically insert a new key signature to the stave with the instrument change. The user could then delete it if that is their preference (it wouldn't be my preference).

It's by design only because I couldn't find a way to design it otherwise when I first implemented the transposition for key signatures some years ago :-). I was aware that it would be nice to automatically add the key change, but there were complications I didn't know how to deal with. Probably it is possible, and may well be easier now. Basically, we'd need to do the equivalent of what you currently have to do manually - insert a new key signature at that point, locally for the staff. In programming-speak, that means inserting a new key signature segment with an element just for this staff.

OK, but isn't that what this issue already was? Your title is better, though - this one implies an existing key signature at the point of change won't be transposed appropriately? Or is there is something else going on here?