The warm-up band, Blunt Force Trauma, gets rolling at about 9:00 P . M . On the first power chord, a whole stack of cheap preowned speakers shorts out; its wires throw sparks into the air, sending an arc of chaos through the massed skateboarders. The sound truck's electronics isolate the bad circuit and shut it off before anything or anyone gets hurt. Blunt Force Trauma play a kind of speed reggae heavily influenced by the antitechnological ideas of the Meltdowns.