My goal is to be able to improvise at the keyboard, sans metronome, and, using the minimum amount of post cleanup, end up with a clean, quantized MIDI file (i.e., for notation importage).
Before I spend two days trying to do this as a beginner, I’m hoping some can suggest a workflow.
I guess I envision something like: Line up first note with a barline, set tempo so succeeding notes align reasonably well, reset tempo and/or realign remaining piece to barline as needed throughout the piece to keep the notes in alignment, then finally quantize. Is this feasible in Ardour?
With MIDI regions you can not just change the tempo after the fact, because your MIDI notes will move according to the new tempo.
But you do can align the bars in Grid mode (press Y) without affecting the recorded MIDI. Here is the relevant page of the manual: The Ardour Manual - Toolbox
I would try the following:
record your MIDI
in grab mode (press G) line up the first note to a bar line (move the region)
go into grid mode (press Y) and align the next bar, and so on like explained in the manual. (Depending on the length of your recording, and how ‘in time’ you recorded, this part could be very tedious.) You don’t need to be very precise, a rough alignment should be enough
once you are satisfied leave grid mode (press G), make the tempo in the toolbar to be an average of the tempo markers, and remove the tempo markers: your MIDI notes should roughly adjust to the grid — in alternative you can probably move or copy the whole region to a place in the timeline where the tempo is constant. I haven’t tried, but it should work
select all the notes and quantise (press Q)
I have not tested this procedure myself, maybe I forgot some step. Try with a short test recording first!