Even when she plays solo, violist Charlotte Hug is in a constant dialogue, responding both to her instrument and her surroundings. The Swiss improviser pushes against the conventional limits of the viola–she routinely changes its tuning, and on 2003’s Neuland (Emanem), her most recent solo album, she gets rich and eerie sounds by loosening or moistening her bow. Her work is informed by unusual settings, with resonances both emotional and acoustic; much of Neuland was inspired by a trip to a former underground prison, and she recorded parts of another disc inside a glacier. She also dialogues with herself by using what she calls “sonicons”–drawings she makes while listening to recordings of her own improvisations, which then serve as visual provocations for subsequent performances. Hug’s playing is full of complex timbres and dense sound clashes, but it never sounds overloaded; she knows just when to let her striking tones and sturdy figures stand alone. She’s in town to participate in the Tabadol Project (see Tuesday), but here she’ll play with local cellist Fred Lonberg-Holm. Considering that he titled his last solo disc Dialogs, they may turn out to be highly compatible partners. The duo also performs Monday at Myopic Books; see separate Treatment item for details. Wed 7/19, 8 PM, Hideout, 1354 W. Wabansia, 773-227-4433. Free.