If you choose to use external music, which is not really required, put on some fine, complex gentle music in another room, loud enough to only just hear in the closed bathroom, not too loud to dominate the sounds of splashing, lathering, eroticised bodies. ‘New Age’ or meditation music or artists like Deuter, Kitaro, Mozart, David Hykes and Steven Micus. Keep to music rather than songs. Leave the rock-and-roll, nostalgia and rave music for another time.