I do a LOT of Audiosnap work with metal music, in fact I'm mid project now doing exactly that.
My workflow is this:
- Record the takes (duh)
- Select each track, enable Audiosnap and set the threshold level to 100% to disable the transients
- If this is a simple drum track with no kicks playing in time with the snare (so you're getting possible flamming), I bounce kick and snare to a new track ** (see note below)
- On that track, enable Audiosnap, drag the threshold slider down until it detects most or all of the hits, adjust accordingly by moving transients around or inserting / deleting as necessary.
- On that track, right click it and choose Pool > Add Clip to Pool
- Select every other track, right click on one and choose Pool > Appy transient pool markers
- Manually tighten or quantize your guide track as you see fit.
- Select every other track, right click and choose Pool > Quantize to Pool
No splits, no crossfades needed, no weird gaps, no endless clips. All of the phase is correct and it just works.
** Audiosnap has a BIG problem with ghost notes and weird detections. What I tend to do is put a gate on the kick and snare track and get them extremely clean sounding (to the point of them sounding bad, but so there's a definite attack to each hit, and no noise between the hits) and the bounce THAT to a new track. You can delete the gates after that. You new guide track will have super clear hits and Audiosnap will be a million times better at detecting the transients.
This get a bit more complex with double kick work where things fall on the same beat, or places where you want to set your timing guide from something else (ie: you have a killer ride pattern which is a bit off but that's where everything follows.) You need to decide what is most important, quantize minus any overlapping hits, then go back a few more times and lock in those remaining transients with the rest of the group. Not ideal but I've had great results from doing that.