As musical director of the Berlin-based new-music ensemble Zeitkratzer, Reinhold Friedl has led the group in performances of a staggeringly broad range of material, including pieces by John Cage and Luciano Berio, Sonic Youth’s Lee Ranaldo, Japanese noise maestro Merzbow, electronica provocateur Terre Thaemlitz, and death-metal pioneers Deicide. (They’re best known for their electroacoustic arrangement of Lou Reed’s seemingly untranscribable Metal Machine Music.) In his own improvised work Friedl explores the piano as a source of pure sound by forgoing the use of the keyboard: he attacks the strings directly, plucking, bowing, hammering, rubbing, and thwacking them, and taps and beats on the instrument’s surfaces. On the duet album Au defaut du silence (Trente Oiseaux, 2001) percussionist Michael Vorfeld bows his cymbals to create high-pitched squeals and haunted-house drones; Friedl responds with gonglike low-end rumbling that seems to arrive in slow motion, like an ominous bank of clouds. Anostalgia (Grob, 2002), a duet with guitarist and reedist Elliott Sharp, has a choppier, more constrained feel. Sharp’s guitar playing often sounds like strangled speech, and Friedl evokes the scurrying of a trapped rat as he races across the strings. He’ll freeze in the middle of some frantic, knotted figure for an interlude of resonant long tones, only to burst out again even more manically. In this show–Friedl’s Chicago debut–he plays for the first time with local sound artist Lou Mallozzi, who’ll contribute electronics and samples. Since the Empty Bottle doesn’t have a piano that conforms to Friedl’s specs, he’ll perform on guitar. Wednesday, January 7, 9:30 PM, Empty Bottle, 1035 N. Western; 773-276-3600.