Best practice for toggling between mono/poly keyswitches in expression maps

I’m sure this has broader application, but if I have a string patch that toggles between mono (“legato mode”) and poly with a keyswitch, what is the best way to trigger that in playback?

Ideally, the playback engine would be able to send the keyswitch when it detects multiple notes (and the expression map would need to be aware of this need), but I could also see doing this with, for instance, a non-printing (does such a thing exist?) expression mark. That’s cumbersome, but would be the equivalent of writing “mono” or “poly” in the score.

Question: is there already a best practice to do this? As-is, I’m seeing a need to export to a DAW to get this done, but I’m sure there’s a better way.

Thank you,

There isn’t currently a way of doing this, but I would be interested to know which library you’re using. Is it not sufficient to just add a mapping for legato?

For what it’s worth, you can make a playing technique in Engrave > Playing Techniques that triggers the appropriate MIDI action and which can be hidden in the score by way of the ‘Hide’ property.

Thank you. That is what I had been doing, but just didn’t know if there was another way.

To answer your question specifically, the Embertones Intimate Strings library, but I don’t think this is an isolated case. (I’m not an expert on the topic, but here’s my impression:)

I don’t think it’s uncommon to have solo patches that are monophonic until keyswitched to poly, so they can take advantage of the legato transitions programmed into the VST. However, imagine writing a solo line for an instrument with a few double stops… this requires the artificial (from an engraver’s standpoint) switching to the poly keyswitch. (The equivalent of writing divisi in a choral part, for instance.) But there’s obviously no notation in a score when this happens.

I think the idea default behavior would be for the expression map to know it’s a “mono until keyswitched” VST and then automatically impose the poly keyswitch when Dorico detects simultaneous notes. Again… that’s /ideal/ and I realize it’s not top of the list. Maybe add to a to-do list to at least consider in the future?

Until then, workarounds are 1) always running the patch in poly mode (which is adequate for sketching purposes, but not for any kind of production mockup) or 2) using a hidden playing technique to affect the switch.

Thanks for explaining - that all makes sense. That’s something we can consider for the future. I’d be interested to hear if there are other libraries that also have this mono /poly mode. Quite a few of the libraries I’ve seen will use the overlap between notes in a legato mode (as opposed to notes struck close together)