Boy do I feel stupid. I tried playing a BB file thru the audio interface and got the same result. Turns out, my headphone jack is stereo, but the 1/4 adapter I plugged into the interface was only mono. The only reason I'm copping to this right now is because some other noob will probably have the same problem somewhere down the line and I'd like to save him some headaches.
(Sigh)


Music is what feelings sound like.

Windows 11, Behringer UMC204HD Audio Interface, BIAB/RB 2022 Ultra Pak Plus