After much testing through the Large Hadron Collider at Cern I have discovered the cause of the problem. Unfortunately there doesn't appear to be a way for me to fix it.
The sound recording works fine if I'm just using sound through my computers audio out jacks. But as soon as I start using my Gamecom 780 USB headset the recording starts going out of sync.
This is the second time I've experienced problems with Action and USB headsets. Plus I've had no reply from tech support whom I mailed a few days ago.
I've tried updating the drivers for my USB headset but that didn't help. I'm pretty much all out of ideas.