i made a diy battery box and encased it in a radio shack project box, but i like your design better because the project box is just too bulky to carry around. well, that and my friend decided we should put a big red button switch on it so it sorta resembles a bomb detenator. getting caught sneaking gear in is one thing, but now my biggest fear is having to explain why i have this sketchy device on me. anyhoo, question for the floor: how long (approximately) does your 9v battery last? do you put a new one in before each show?