The day JoAnne Powers picked up her first saxophone, she decided to test it out in front of a strip mall; within 20 minutes she'd made two dollars, and five months later she was supporting herself as a free-jazz busker on the streets of Madison. Over time she's developed a massive tone and enormous stamina, inspired partly by the example of free-jazz sax icon Peter Brotzmann, but also by her need to be heard over wind, traffic, and the chatter of passersby. She's also developed a facility on soprano, alto, tenor, and baritone that belies the fact that she didn't touch a sax until nearly five years ago, at age 26, though she's played various brass instruments and guitar since grade school. She's released several CD-Rs: Mixed Metaphors (2001) captures a concert by Mutually Assured Distraction, a duo with percussionist Bob Cozzolino, that displays her penchant for anarchy and sardonic humor, and on Metrocide VS JoAnne Powers (2002) electronic musician Metrocide uses Powers's gruff multiphonics and high-pitched wails to create a withering, Merzbow-like sonic barrage. But Legendary Weapons of Free Jazz, her upcoming self-released CD, is both her most accomplished and most jazz-oriented work to date. Bassist Jennifer Pendur and drummer Paul Baker are equal partners on the opening track, "Fault Lines," which explores restrained, rustling interplay and tart agitation; on "Blamiet Huiett," she pays tribute to baritone saxophonist Hamiet Bluiett by squeezing out urgent, spiraling lines on her own bari over the rolling cadence produced by the rhythm section. Powers has played Chicago streets and subways, but this is her first club gig here; she'll be joined by Pendur and Baker. Wed 2/16, 9:30 PM, Empty Bottle, 1035 N. Western, 773-276-3600 or 800-594-8499, $5.