Swiss guitarist Stephan Wittwer is a master of incongruity. He can generate blinding noise or subtle texture, jagged shapes or smooth melodies, swank jazz chords or blazing speed-metal sweeps. Wittwer first wowed Chicago audiences last November at HotHouse’s FMP Festival. With the all-star international ensemble the Cowws Quintet, he showed his abilities as a free improviser, skills he honed in the 70s when he made a pair of classic duet records with trombonist Radu Malfatti. In a flash he might jump-cut from unamplified strumming to supersaturated distortion and feedback. Wittwer first unleashed his free-metal mania on the 1989 solo CD World of Strings (Intakt), a torrent of noise that sounded as if the floodgates at Hoover Dam had opened; imagine Derek Bailey guesting with Anthrax and you’re getting warm. Sludge 2000 are the group vehicle for his collision of improvised music and speedcore (I saw them burn down the stage at Rote Fabirk in Zurich in 1992). Wittwer is as nimble and nasty a metallic pickster as you could want, embracing both whacked-out humor and dead-serious musicianship. But Sludge 2000 are much more than empty metal virtuosity, with a tremendous noise quotient, instantaneous stop/start structures, and an inventive open-endedness. Drummer Lucas Niggli also plays in the fusiony Kieloor Entartet; he’s a fluid drummer with no end of energy. Rounded out by bassist Marino Pliakas (doubling on acoustic guitar), the trio will be augmented in its first Chicago show by local reed players Ken Vandermark and Gene Coleman, multiinstrumentalist Jim O’Rourke, and keyboardist/ARP-synthesizer specialist Jim Baker, who had a love-at-first-sound-bite encounter with Wittwer in an ad hoc set at the FMP fest. Monday, 9:30 PM, Empty Bottle, 1035 N. Western; 276-3600. JOHN CORBETT

Art accompanying story in printed newspaper (not available in this archive): photo/Will Spiller.