I do not think this is possible but was just wondering if maybe anyone knows of any tricks for something like this.
For example, if you have some kind of drum kit based virtual instrument where each sample is assigned to a specific MIDI note, and you would like to map each separate MIDI note to its own mixer channel for separate processing, for plugins that do not offer this capability built in.
You could try to send the MIDI output to other tracks/busses, where you filter the specific notes (e.g. with x42 MIDI Filter Collection). If your drum kit has a lot of pieces, it can be a lot of work though. Also, I guess you have to replicate the drum plugin in every track.
As an alternative, you can use the “LSP Multi Sampler Direct Out”. It loads samples and when you add it in Ardour it’s possible to automatically send each audio out to a different channel.
I like piergi’s solution. Add a MIDI track for each note that needs special mixing focus (kick, snare?) and put an instrument on that track. Then all the extra stuff can remain on a single track.
This allows you a lot of flexibility as you can not only try different patches and mix settings, but even different drum-instruments entirely for each sound.