seems like a bug!
if you open up your clip in the timeline and than sync your audio to it manually, it will work.
i hope apple will clean this up in the next update.
i think, if you have footage which is most the same by format and codec, the sync-feature work.
i did two videos, one with my ipad and one with my isight.
in final cut pro x i set the audio to mono for both and voila, it worked.
i hope this helped!
I have the exact same problem, all my recent work at 25fps cannot be synced with my Zoom H4n files at all, however, on messing around with the camera(5D or 7D) and zoom, i put it to 24pfs and the zoom to 44.1khz at 24bit, it synced perfectly....great, however, i want to shoot at 25fps....there must be a way? I even tried to convert the 25fps footage via various softwares to conform to 24fps and sync it that way....no good....doesnt work at all, is FCPX only suited to 24fps or have i missed something?
So let me get this straight:
You've got one long piece of audio recorded on a Zoom, and it needs to be sync'd to several different video clips recorded on 2 different cameras.
Your problem is that when you sync audio to those video clips, the same Zoom .aif (or .wav) keeps stacking again and again.
I can't solve your problem, but I can offer a workaround that might help.
Since the audio probably has several different starting and stopping points, why not break it into pieces in a third-party audio editor (I use one called Twisted Wave -- yes, at www.twistedwave.com -- great little audio waveform editor for Mac -- and no, I'm not on their payroll, just a loyal customer). Break the long audio file into shorter files, putting the cut points at the gaps between video takes.
Then sync *a* video clip to *a* piece of audio. It ought to work.
Wouldn't have the problem if your audio guy just remembered to stop at the end of a video take and then start recording again with each new video take. You'd already have the audio clips separated just like the video clips are separated and wouldn't need to resort to this.