SEPT 19 Thur TEARS FOR EARS Tonight the Lab kicks off the first in a series, as curated by Kristen Dilley and sound-arts organization 23-five, of explorations into the musical and performative aspects of sound. John Bischoff, Michael Peppe, Cheryl E. Leonard, and Matt Ingalls present industrial and computer-driven audio experiments, musical behaviorism, compositions on a box-spring mattress, and even a clarinet or two. If all this sounds like fun, come back for the next three Thursday-night installments of 'Sound Unwound' and have a look and listen to an eclectic range of artists offering everything from punk and jazz to sampled noise and environmental collage. 9:30 p.m., the Lab, 2948 16th St., S.F. $5-$10. (415) 864-8855. (Neva Chonin)