Experimental guitarist Nels Cline is best known as a member of Wilco, but he’s enjoyed such a long and diverse career that just about any profile of him would have to be considered approximate. This short documentary shows him rehearsing a side project at Fantasy Studios in Berkeley, and the talking-head segments reveal him to be a quiet, almost professorial figure, a former philosophy major who aims for a balance between structure and freedom in his music. “You’re trying to get over with people who don’t really understand what you’re doing,” he remarks at one point, betraying the isolation of a musician’s musician. Yet inside the studio walls, collaborating with violinist Carla Kihlstedt, clarinetist Ben Goldberg, and keyboardist Yuka Honda, he’s completely in his element.