Does QuickTime automatically record stereo audio into mono?
I'm having the same issue (Scarlett i2i USB hardware):
Can&#39;t get QuickTime to record in stereo
I confirmed that Audacity records in stereo - even at the same time as QuickTime records in mono.
I called Apple and they were pretty clueless. It's possible (and painful) to detach the audio track from the QuickTime movie and attach the Audacity track instead - iMovie can be cajoled to do it reluctantly. I haven't found a better solution yet.