Audio Drift for long concert

Ok, here is where i'm at with this. I broke the 2.5 hour concert audio file form the board down into 5 min clips. I then created a multicam sequence, with the board audio, and cam's a, b, c, and d. I dragged the 5 min clips up all on to one audio track, deleted the audio from all teh cameras except camera d. i open the premiere project in audition. i start at the end (last 5 min clip) and zoom in real close and align it (checking the beginning, middle, and end of the 5 min clip). so far i haven't done any stretching, but i do notice that when zoomed in real tight, there are tiny gaps between the 5 min clips. This seems to be working, i've only done a few so far and working my way forward. I'll let you all know the progress

hmm.  sounds odd.  OK, line up the audio at the beginning of the video.  Go down to near the end and find a place to synch for example the first sound of applause often works.  I put  markers on both the timeline and the video and audio clips.  Keep adjusting the speed of the audio clip using the speed duration option in the clip menu (or select the clip in the timeline and hit command-j (at least on the mac) and make sure maintain audio pitch is checked until the markers at the end line up.  As I said, if you've got the full cc suite, sending to audition will more than likely do a better job.   You might also be able to use logic to do the speed change.  It's been years since I worked in logic...  

gotta say I've been working with multiple cameras and a separate digital audio recorder that were not synch locked for many years without any noticeable synch drift issues in programs well over an hour.   How was the audio from the board recorded?  if the sampling rate is 44.1, I'd resample to 48k to match the video cameras (assuming you were using video cameras that record 48k).

Sounds like it's probably caused by how the audio board was recorded.  I once had a multicamera shoot with separate audio recorded professionally and the audio would not synch up.  Turns out the audio engineer and added timecode the the wave file that was causing the problem...  Anyway, you can change the duration of the audio file to match the camera audio without changing the pitch...  Audition will do a much better job than doing it within premiere (at least in my experience).  If you need help figuring out the speed adjustment, post back...  I've figured out a few tricks...

Unless sync locked all cameras and audio recorders will drift over time, how far are your tracks out at the end of the recording?

What is the frequency of the separate audio against the camera audio files? I've known of situations where changing the frequency was a fix.

But a couple times, it was a simple time-change for one audio file that fixed things.

Neil