In the loosely defined underground genre of experimental noise, one man's cement mixer is another man's celestial choir. For the local racket merchants in Page 27, whose carefully sculpted dissonance has soothed and jangled nerves in the Queen City since 1994, noise is a many-splendored thing. With a shape-shifting audio assault that fully utilizes feedback, drum loops and all breeds of digital-effects manipulation, the veteran four-track outfit explores the infinite reaches of atonality and sound collage. Part of the edgy Backwards Records collective, the 27's rotating lineup features Robot Mandala's dueling laptoppers, John Rasmussen and John Gross (whose day job sometimes involves taking aerial photos from helicopters), plus the noise-mucking, uni-monikered Ezra from Firecracker. Broadening its scope from a backlog of oddities including Moon Man and Turntable Terrorism, Page 27 joins three Los Angeles-based noise acts, Half Normal, Adam Overton and Raven Chacon, plus Boulder's own ambient Encomiast, Sunday, October 10, at the Old Curtis Street Bar. Like the old saying goes: sound mind, sound body.