The novelty of its punk posturing has long worn off, but the Kronos Quartet has survived as a niche player. Never quite compelling as an interpreter of the classical repertoire, the hip Bay Area-based foursome thrives instead as an apostle of multiculturalism and a champion of the new. Over the past decade, commissions by the Kronos (close to 50) probably accounted for a sizable chunk of the chamber compositions produced in the world, and though a Kronos concert--invariably filled with premieres--may end up with more misses than hits, the sheer excitement of encountering the new is often a reward in itself. This appearance is part of the Jam/Goodman New Music Series. Likely winners on the decidedly eclectic program: Marcando tempo, by the innovative Brazilian jazz musician Hermeto Pascoal (a world premiere); Quartet no. 2 (Quasi Una Fantasia) by Polish avant-gardist H.M. Gorecki; and John Zorn's Cat o' Nine Tails, a collage of fast-paced musical moments inspired by the surreal scores of Loony Tunes cartoons. In the unclassifiable category: Beat Boxer, a "rap string quartet" by Michael Daugherty. A new string quartet by Philip Glass is also promised, but I suppose we can forgive the Kronos for its momentary indulgence in the passe. Tonight, 8 PM, Park West, 322 W. Armitage; 929-5959.