This is all like drinking from two fire hoses at once. But I'm working my way through the problems to the solutions. I got an email today asking me to video a recording for a group I regularly play with. But the rub is that I play guitar and bass. So I got the notion to record both and meld them together somehow. [Melding "somehow"... that's the rub right now]. ... So I mounted mounted my Canon 5D Mk III on my desk, ran my guitar into the M4 and then ran the headphone jack back to the camera. I can't answer why I did it this way, but I actually ran the recording in and THROUGH Reaper. I have my monitors hooked up so I don't need the headset. I used a standalone metronome (Boss DB-90) to keep me honest. I would have run a click-track... except... ... After recording rhythm guitar I came back to record bass (with the camera). So Reaper played back the guitar track as I recorded the bass track. Now on the PC I have both tracks separate, but on the bass video recording has a high quality (un-tweaked) recording of BOTH rhythm and bass. There's lots to decide on how I want to procede going forward, but at least I know that I can get decent audio right on my camera video recordings, and I guess that fills one of my needs for quick and dirty demos. BTW... The MOTU M4 is everything I could have hoped for. I'm glad I waited for it.