In uni accomodation me and my partner in crime reigned terror on the annoying people in the house (shut in, selfish with the cupboard space and anything that can be plugged in, generally irritating) with practical jokes. Worth a try. You can start by dialing a decent sound into his gear, or be subtle and trick him into thinking/believing/spouting absolute nonesense about gear and music. Start by, I dunno, trying to tell him that right angled cable jacks sound better, maybe he'll believe it....and if he does....:D