Hello, I always tried to understand if it is possible to fix small tempo mistakes in the performance of a final stereo audio, without introducing artifacts. I am still confused on how to proceed, so I’d be very grateful if any better users could help me!
What I do is cut the audio at the most strategic place(s) (basically between notes) that have the lowest volume. Then it is a matter of moving the cuts to be in tempo. I do this “by ear”. As applicable I use crossfades and volume fade ins/outs to reduce artifacts.
This usually works pretty good but, as necessary I sometimes need to reduce volume of the small moved clips, add short effects like reverb to the area, try to replay another track to somewhat cover/blend things.
You are saying “small tempo mistakes”. So it’s not like you are changing the tempo of the majority of the track.
Also assuming that you can’t re-record these sections using the punch in/out function.
You need to do some cutting then moving. Zoom in as close as possible to actually align the sound wave form where they are similar. If possible, overlap them a bit. Then it’s a matter of crossfades and fade ins/outs.
Typically I get pretty good results when I do a solo listen to fixed tracks. I never made a project using a single mono track of one instrument so… it will be a bit tougher because apparently you can’t cover the area with effects or a percussion hit or some other instrument/sound that would smooth and cover things up a bit.
Prock pretty much covered the general editing process. And it is possible that just doing a straightforward edit and move might sound fine. Only way to tell is by trying. In any case I’d make several versions of the initial Track so you try stuff out.
With a cut & move approach you have 2 potential problem sources. One where the audio parts overlap & another where there is a gap. The overlap can generally be handled by picking a good place to cut, shortening the Part before the cut to minimize (or eliminate) the overlap, and finessing the crossfade. The gap can be trickier because sudden silence is quite apparent. However you might find that some reverb on the entire track covers the gap fine. Or say you’ve cut your audio so you have Parts A, B & C where B is a bit late so you move it closer to A which leaves a gap between B & C. Try dragging the beginning of C so it overlaps the end of B by a fairly large amount. Now play with the crossfade between B & C.
A totally different approach would be to use the Tempo Track with your Audio Track set to Musical Time Base. Now if you want to move a beat earlier, momentarily increase the tempo a little bit before the proper beat position and then reduce the tempo back to normal.
Doing stuff like this is so dependent on the specific source material that the is no single correct approach.
Also if this is just a one off situation you could download the 30 day unrestricted demo of Melodyne. It will let you just drag notes where you want and it stretches and shrinks the adjacent audio automatically. If you do this make sure to render the track so you don’t loose the edits when the demo expires. Of course this will cause you to develop an overwhelming desire to purchase Melodyne.
When you say correcting tempo errors in a “final stereo audio” what exactly do you mean?
Are you talking about a full mix of a song?
What is your idea of a tempo error? Sloppy playing by one or more musicians inside of the mix?..whole band speeding or slowing together? Other?
Basically the question is too ambiguous to give a simple answer.
No-one has mentioned warp probably because you specified no artefacts. Cutting and moving audio has no artefacts, but it can’t really correct for a band gradually speeding up and slowing down as they proceed through the song.
If you have a problem that needs correcting you have to try it regardless of artefacts…then you listen to the result and have to decide whether the artefacts are more or less acceptable than the original problem.
Yes Grim, I meant something like a solo piano track that speeds up during a recording. Moments where the playing is not on the grid. Is time warp what people apply in this case? I’m new to time warp so need to investigate its uses.