Think of the San Francisco Tape Music Festival as a cinema for the ears. It's a "see nothing festival," where the audience sits quietly in a very, very dark theater to absorb the sounds. Organizers set up a high-end surround sound system with 24 speakers, and with nothing to get in the way, the music can fill the entire space. To be clear, tape music doesn't mean just anything recorded on tape; it's also a way of approaching music. "The pieces we present transcend simplistic notions of music," organizers say. "The recording/playback media itself is treated not as a stand-in for an absent performer, a poor man's orchestra, but as a vital and unique territory for exploration." This year's program features more than 20 composers, including a recorded invocation from the famous inventor Alexander Graham Bell, classic electronic compositions from composer Francois Bayle, and Steve Reich's 1966 tape-loop piece "Melodica."