BJÖRK is a whirling dervish of brightly colored clothes and avant-garde noise, an outlandishly designed package meant to entice and challenge her audience. In spite of her girlish and playful demeanor, however, the 41-year-old Icelandic performer is a meticulous artist, often spending years to make thematic works bursting with cutting-edge sounds. Her new disc, Volta, is a meditation on feminism, justice and impulsiveness, and features collaborators such as electronic producer Mark Bell and Timbaland. A huge cult star, her Mon., SEPT. 17, concert at the Fox Theatre is already sold out. 8 p.m. 660 Peachtree St. 404-881-2100. www.foxtheatre.org.