How to Time Stretch/Pitch Shift with maximum quality?

[Danny Hard]

Is ableton the best DAW for doing this?
What software can I use to change the track's BPM (and the pitch, like using Re-Pitch) while losing the minimum quality possible?

Thanks

[braduro]

I haven't formally compared Ableton to Logic, Trakor, nor Protools, although I am certified with the later, so this is just my ears talking: as you have gathered Repitch is not using granular methods to speed up a track. But to suggest that a tune further astray from its original tempo is a more pure, less degraded approach is a bit mis-led conclusion IMHO. If you actually want the pitch shift to correlate with the time change, then I don't think you need to try trakor to see if it has a better quality, for example. A better workflow for your purposes, certainly possible.

Max quality: Unwarped, right?
Next Notch down: repitch mode, with only two warp markers to anchor things in place, left at clip segment tempo. Then shorten the tune by skipping a verse, 16 bars of whatever, etc.
You get the idea.

There are papers about this which discus the summing and bussing inside Ableton. I'm of the camp that is willing to believe them.

[Khazul]

AFAIK Live 8/9 uses Elastique Pro v2 (Licensed from zplane in germany) as do Steinberg in Cubase.
Live 7 and earlier used the original Elastique (now called Elastique efficient).
Traktor uses Elastique Efficient v1 (though I have heard it uses Pro v1 - not sure).
Protools uses its own (or something else) and I have no experience of it.
I cant remember what Logic's is like, its not Elastique AFAIK.
Propellerhead Reason/Record use their own in-house algorithm.
Melodyne have their own thing, but that oriented for solo voice and polyphonic instrument re-pitching and not general use. It very good for what its intended for, but I wouldn't use it for general stretches.

Elastique V2 pro is one of the best out there, however the headache with Live is the warping that calls for non-linear pitch/tempo changes which can significantly reduce the quality compared to a purely linear stretch. To get around this in Live - only allow a marker at the start and end and try to live without any in the middle. If you have lots of warp markers and especially several ina bar, then expect issues as some of these may be significant stretches if only for a very short time.

For this reason - simple linear stretch in other software can sound a lot better - no warbles etc.

The best I have found for more extreme stretches is that in Propellerheads record. The headache though is I think in earlier versions of reason/record it was coupled with really bad sample rate conversion which may have been involve in the re-pitching in same way. The end result was very musical/pleasing sounding, but not great technical audio quality. That said, it was still my preferred method for more extreme stretches (extreme changes in tempo and/or pitch).

In Live 7 and earlier I used to repitch in a couple of steps - first repitch as much as possible using an old scholl re-pitcher (live's re-pitch mode). 1 semitone up is a tempo increase of about 6% and visa versa. So I use that to get to pitch if the resulting tempo change is also in the right direction (however the result is at the mercy of some kind of SRC algorithm, most are fine, some can be really bad). Then I used to stick the result in propellerhead's record to get it the rest of the way. You can do the same in live as well. Finally I may do some fine tuning of groove in Live (which will cause micro-warps, which tend to result in warbles when stretched away from the original pitch/tempo).

In Live8/9 with complex pro mode, I don't believe doing a separate pure re-pitch actually buys you anything.

In the end it depends on the material - check for unwanted granular synthesis type artifacts or little warbles and in particular loss of impact on transients. In previous version ive gone to the extreme of mixing two warps together - one just using a regular complex mode and another using pure beat mode. The beat mode was processes by phase cancelling through an instrument rack with a compressor to reveal only the transients (with everything else silent, so very little pitch information in the result) which I could mix back in to revitalize the killed transients.

With Live 9 I have never felt the need to go to such an extreme as transients are much better preserved now and the result can usually be fixed with a transient enhancer (SPL for eg) or a good expander (fabfilter pro-g) or some inverse compression (the phase cancelling trick with a compressor mentioned above that basically turn it into an expander).

[102455]

Danny, can I just ask what your reason is for wanting to do this?

Are you playing the tracks back on something that doesn't have a pitch control?