Those who do not know the experiments of an elementary school me, are doomed to repeat them.
Really in elementary school I read about binaural recordings (when I wasn't learning to program computers). I theorized that if binaural recordings made with mics placed a head width apart played back well on headphones, then recordings made with mics placed where the speakers were would place back well through those speakers.
Unfortunately I didn't have two mics. So I took the RCA plugs on the speakers of my mom's Soundesign and attached mono 1/8" phone plug adapters to them, and used the speakers as mics. I'm guessing (now that I have a bit more knowledge) that the "crossover" on the tweeter kept it from contributing any usable signal, but bass to midrange was recorded pretty well. Listening to the playback from a position directly between the speakers gave a pretty haunting image of people walking around the living room and mumbling.