Well, I can't verify this story, but a few years back, as the story goes, here at a large LA area aerospace firm I work for, several technicians moved a large vibration test hydraulic shaker head (used to vibration test a 12000 lb satellite) up against the building's 30 x 100 ft roll up steel door. They commenced to play Xmas carols until the local constabulary arrived. Not exactly a low distortion device, but very effectice.