At first I thought this was a tempo issue when exporting my stems from fl studio to cubase. But when I zoomed in close enough and lined up the tracks they were perfect (ie. no stretching). The mp3 master track seems to be delayed by about 30 ms (ie. 30 ms of emptiness at the start) as compared to the separated, mixer tracks in wav format. Why is this the case?
Here is a relevant answer/troubleshoot steps to go through. This is an excerpt from x42 posted in Ardour forums:
"First thing to check: is everything in sync on your machine before export?
Next step: re-import the exported file into your session. Does it line-up 100% ? (check visually and/or invert the polarity of the imported ones (mixer phase invert button) the sound will cancel out if they're 100% aligned)
If both are true: then either
(A) your session was not in sync with the other when you started recording (B) the file is not imported at the correct position in the other DAW."
The thread (linked below) raises some good points. One thing you could try doing is setting a track delay on the wav channel within the DAW to create a set delay, since it seems you know the exact amount of delay happening.
It has to do with the MP3 codec algorithm. I don't know the exact science behind it but it's something you have to deal with when using MP3's because it can't be prevented.
I don't think anyone would advise you to migrate your tracks/stems using the mp3 format.. especially when using them with uncompressed files in the same project. Not forgeting the loss of quality/imagery in your production.
Recommend mp3 only as a final mix format for distrobution on iTunes etc..
look this issue is everywhere, my issue is i send people mp3 beats to record on but i mix and master on waves.. simply i delay the beat by 1100 samples.. idk how many ms because i have this time adjuster on my protools, so what i did is i set the grid to show samples, and counted themm 1100 sample delay on the wav beat makes the beat insync with the recording that was done on the mp3