1. When the walls of the bathroom seem to amplify every rectal sound by thousands and give a sense of echoing.
2. Phenomena that occurs when you sing in the shower. Even if you sing very quietly the whole neighborhood hears you and it sounds like shit.
"wait! go into the bathroom i want the full surround sound bacoustic"
Fred and Jim go past a house in the morning and hear crap singing coming the bathroom:
"damn, hes got bad bacoustics!"
"thats jay-z house ass rag!! and hes not in the bathroom, thats his recording room"