That setup sounds ideal! - Any chance you could tell me which actions I need to map to those keyboard shortcuts in Reaper?
Also, what's the general process? From what I understand, you find the transient, split it, then you need to move the transient to where you want to align it.
What I'm not clear on is what happens to the audio either side of the split. Does the audio before the split move back (therefore becoming out of time), or does it stretch to fit? What about the audio after the split - does that also stretch to fit?
I'm worried that I could make something that sounds totally unnatural, or find myself with a track that is totally out of time.
I'll look up the actions when I get home to my music comp.
As bryan_kilco said, usually when slip editing you would do the entire track from start to finish. You start at the first transient and create the split. You can then slide the audio that lies after the split point backward/forward without altering anything before the split point. This will, of course, move things downstream as well, but again the idea is to do the whole track, so you'd just move on to the next transient and repeat the process. Ideally, if the track is played fairly decently to begin with, you never really move anything THAT much, so nothing should get thrown off too bad. I always listen periodically, though, to make sure that everything's still ok.
If you just want to edit a couple of hits/transients without altering anything else, it would be better to simply split the beginning and the end of the section you want to nudge and then slide things around within that.
Either way, you'll need some sort of reference in the same window as the audio you want to edit. Generally when I do bass, this will be the kick drum track. Of course this means you need to get the kick track/rest of the drums grooving the way you want them to before doing the bass, so if you're not happy with your drum track, fix it first. Otherwise, it's really just as simple as slice, align, and scroll on to the next transient. Choosing the split points will become second nature with a little practice. Generally, if a transient is late (i.e., I want to move it back), I'll split the audio right
before where I want the transient to end up, and then drag it back. If the transient is early, I'll split right before the transient itself and then move it forward. You'll want to turn "auto-crossfade on split" on as well, so that it crates a crossfade with every split.
I know Adam Wathan used to have a couple of good REAPER slip-editing demos on YouTube, which might be worth checking out.