Beams of Light uses a 4-channel .wav file. Here's a magic invocation for getting the graphics to the scope (via ALSA card 1, presumably a USB audio device) and the sound track to the speakers (built-in audio, ALSA card 0).
kbare@newharmony:~/beams_of_light$ AUDIODEV=hw:1 play beams_4ch.wav remix -m 1 2 gain -h rate 44100 >/dev/null 2>&1 < /dev/null & AUDIODEV=hw:0 play beams_4ch.wav remix -m 3 4 gain -h rate 44100 >/dev/null 2>&1 < /dev/null &
The play command is part of sox.