on a related topic, I've found the command described above to be useful in all kinds of situations. (at least, in the kind of projects I'm typically involved with)

I frequently merge multiple audio files of the same cover song and try to get them lined up. The one I consider to be the main file gets run through the ACW to tempo map it.

Subsequent audio files get dragged so they start at the same place as the 1st track. But usually, the two tracks don't remain in synch. Here's one way to force them into synch:

1) place the two clips side by side so you can compare peaks

2) hilite the 2nd track and use the PITCH SHIFT OR TIME STRETCH AUDIO command to make it about the same length as the 1st track. Let the peaks be your guide more than the actual length of the clip.

3) if both tracks don't play in unison without going out of synch, UNDO and change the stretch parameter, then restretch. Err on the side of making the 2nd track SHORTER than the first track, if all the peaks can't be lined up.

4) then work your way from start to finish, hiliting and dragging the mismatched peaks of the 2nd track to line up with the first track. This will create gaps, but we'll fix that later.

5) when the peaks are lined up in both tracks and they sound somewhat unified except for the gaps in the 2nd track, then...

6) go back thru the 2nd track and for every gap, hilite a section of audio immediately before the gap that is about the same size as the gap. Then right click > PITCH SHIFT OR TIME STRETCH AUDIO > 200%

7) that will fill the gap. But there will probably be a small artifact where the cut took place. After all of the gaps are filled...

8) hilight the whole track and EDIT > CONSOLIDATE AUDIO REGION. This will heal all of the cuts and create a unified track.

This procedure isn't going to yield high quality results, but its useful when creating Frankenstein compilations from a bunch of different source files. I've had good results by bringing the better track forward. Considering the fact that backing tracks for live performance are never going to be listened to in an audiophile environment (lots of background noise and talking, and quite often these days one or more TVs may be playing in sport bars) the imperfections and artifacts easily get lost in the environmental noise.

https://www.dropbox.com/sh/ey71h8ep047758h/AAC12jNM0Hz9Q8zsh5iDeqNHa?dl=0