Instrument Changes

[rpatters1]

Right now, instrument changes within a part are not possible. I would like to offer some ideas and observations about this as we move towards a solution.

Please to heaven not layouts.

Layouts as currently defined are fraught with issues. For one thing, which layout is the canonical layout? (See #478.) Layouts are a bad choice mainly because

• instrument changes happen at a musical location, not a location on a page or system, and MNX should capture that explicitly.

Instrument changes in parts

At least two major software packages, MuseScore and Finale do instrument changes on the part. This is a perfectly functional method, but for those programs it precludes a feature that neither of these (currently) handles well: separate piccolo and 2nd flute staves in a score layout vs. combined on a single staff in a part.

But this is where mnx layouts shine and seems like exactly the situation to exploit them. Would it help to have an instrument tag similar to voice for staff source?

Nevertheless, whatever solution we come up with should ideally be able easily to collapse into instrument changes on a part in the target program.

Introduce the idea of players and instruments instead of parts

I haven't worked much with Dorico, but I have the impression this is how Dorico works. There are players and instruments rather than parts. The main thing I don't like about this is that it can potentially be challenging for an importer that does not fully support it.

Finally, I would like to reiterate (because I feel strongly about it):

Transposition is not tied to parts nor to instruments.

For horns and trumpets, at least, it is more akin to a change of key signature.