QuickTime won't record in stereo
ChallengerSteve noted in a post from 2016 or so, that when using an iTrack Solo to make a new QuickTime audio recording, the audio is on the left channel only - not both channels.
I have the same problem, and after reading the posts from back then (you can search for it BTW), I decided to try using the MacBook microphone as a test - instead of the iTrack Solo.
Sure enough, the audio was on both left and right channels, as desired. Therefore - the problem is in the way the iTrack Solo is sending audio through USB, only on the left channel. Not good. I might try an iTrack Scarlett.
Like ChallengerSteve, I was unable to use GarageBand or iMovie to move the file's audio onto both channels. Very annoying. I have a nice MXL990 microphone, which doesn't pick up "poppin' p's". I was trying to record audio and PC game video separately - using OBS to capture game video and audio, but having a separate channel for narration using QuickTime. OBS doesn't allow that since it mixes all audio sources together. Thus the need to record onto a separate device for narration.
I know that recording a separate file for narration will drift over a long video, but that is easy to fix in iMovie - just shift the audio segments a bit as needed.
MacBook Air (M3, 2024)