Quantizing audio

Question

Quantizing MIDI is a piece of cake and every program/DAW that supports MIDI does it. But say I'm working with raw audio instead, say maybe a guitar line I just recorded, and the performer's timing is a bit off and doesn't match the click as well as it should. If I want to line it up with the tools I have now, I open up the guitar audio and click track in Audacity and manually delete or copy the waveform so it lines up. There has to be a better way.

So what tools could I use to "quantize" recorded audio? (I use Cubase SX 5, but I'm open to trying other tools if needed.)

(Note that I'm not asking whether or not I should do this instead of re-recording or anything else; I just want to know if it is possible and how I could do it.)

Answer 1

I use Ableton Live's warping feature for this. Instead of cutting or copying parts parts of the audio waveform (like you're describing in Audacity) it attempts to stretch the recordings to the locations you specify.

I've never seen a timestretching algorithm that didn't color the sound at least a little bit (which makes sense, really) but I've had pretty good luck with it for small, quantization-level modifications.

Answer 2

I've been pretty successful by doing hard core edits. Using power based instead of gain based crossfades help masking out phase/colouring issues.

I could probably get away with some bass notes, or even guitar. Staccato, or heavy legato notes are usually easier. Protools make this a breeze with dual timeline feature (transport, edit timeline) and the ability to snap anything, at any point to your cursor.

Elastic audio has @BenV suggested is a pretty good thing to look at.

Any kind of warping will depend on the algorithm you are using though. If you do go for something like that try them out. Won't say one is better than the other but may be more suitable than the previous one. For instance, try editing guitars with Polyphonic but then try other presets or even offline processing (xform). Protools will also allow you to use other codecs (with special conditions).

Answer 3

If it's staccato enough to be automatically split, then Propellerhead ReCycle might help. It splits samples into parts, and let you rearrange them and indeed play them from a sequencer, so that you can quantize them like that. Could be worth a try.

Answer 4

In Reaper, you first tell it to split a clip in each transient; then you can move the splits to their right places, or change the fades between them, in group or individually; or you issue a second command to have the DAW align the splits to the project grid, still retaining individual control. Not a tool -- it's done directly in the arrangement.