Unless I'm totally misunderstanding the Mix Audio Channels node, or perhaps it's not working on M1.
What I'm wanting to do is mix pre-recorded audio together. Tried all manner of messing reconstructing the audio frames using the timestamp from a single source of audio frame rate, but no luck.
Maybe just busted on M1?
The result of putting two audio channels together is something that sounds like it's literally alternating between frames of audio, which slows audio to half speed and makes all kinds of glitching.