not able to sync vocal from "slave" project to actual project

[doofus]

ok..I bounced out a rough mp3 instrumental mix of a tempo-mapped project to a collaborator, starting on a bar line (not 1, but perhaps 3 or 4..defininitely on the line though). The original project had a considerably fluctuating tempo, but was accurately tempo-mapped. They dropped the mp3 into a fresh Logic project without setting a tempo (so it defaulted to 120) and recorded some vocal tracks. They sent me the fresh project with the vocals, I comped them-working off the fresh project they'd sent. When I dropped the vocal comp into my original project, I couldn't get it to lock up to the tempo map...it's floating all  over the place. I tried dropping in the rough mp3 instrumental bounce I'd sent them and had the same problem..by halfway through the song it was wildly off. Seems to me it should be following the tempo map, no? I tried turning on FlexTime for the vocal I was dropping in, but it didn't seem to make a difference. I'm having trouble understanding what is going on, since the mp3 I bounced out in the first place *should* play in sync with the track it was bounced out from, no? So if a vocal was added on top of that, shouldn't I at least be able to manually drag it into place so it sounded "right"? But no...even if I line it up really close with the downbeat at the top of the piece, it drifts off prettty quickly. same goes for the instrumental bounce I made; it won't play in sync with the multitrack project that it f$@%ing CAME from..arrghh. Oh and by the way, there doesn't seem to be a pitch difference at all, just a tempo difference. So my suspicion is that this is because of the Flex-Timing that's going on in the original project, and the fact that they recorded the vocal onto a "slave reel" (as it were) that had none of the FlexTime information embedded in it (?) Opinions/suggestions appreciated, thanks!

[wonshu]

SMPTE lock those vocal regions. Read up on how to make SMPTE work to your advantage when moving material between two projects with different tempos.

Then import those regions to your other project.

If you want to be 100% sure, you

- SMPTE lock everything in the vocal project

- make a tempo change (without actually changing the tempo!) at a barline

- copy (or write it down) the SMPTE from that tempo change

- import the tempo track from your main project

- make another tempo change at the bar where you had the tempo change before (again, without actually changing the tempo)

- select all (!!!) tempo changes in the tempo list, double click the SMPTE code of the bar where you copied it earlier and paste (or enter from your written down notes) the time code here.

Now you have your vocal project tempo and time (note timecode!!!) aligned with your main project and you can just import the vocal tracks into your main project.

As a side note:

I would not send mp3 to people as prelay tracks. It never syncs sample accurate to anything. Send .wavs or .aif.

Edited April 28, 2022 by wonshu

[doofus]

I tried the first part of your suggestion (SMPTE lock the vocal regions). Moving them (either by exporting them, dragging them, or copy/pasting) seems to unlock them however; the manual confirmed that this is the case. So, as this didn’t work, I’m not sure how to move them from one project to the other without this happening. 
 

if you can point me to a link that would help me-a bear of very little brain-understand how SMPTE  works in situations like this, I’d appreciate it. My only experience with it was years ago, when I’d stripe a tape track with SMPTE code so I could lock it to a sequencer. 
 

I haven’t had time to try the second, more complicated part of your answer yet. I took the quick and dirty way out, by cutting the vocal up and Flex-Timing it into place, which I’m this instance  worked fine. Still would like to understand the subject better though-thanks for your time!

[JakobP]

I wouldn't use mp3 for this, have you tried an uncompressed format like .wav or .aiff ?