Clogs are four improvising classical musicians from Australia and the US. The group is part of a wave of challenging, emotionally resonant classical music that's crossed over to non-classical audiences (a la Sigur Ros, Dirty Three, The Books, Rachel's). Clogs' third album, "Stick Music," is a tour-de-force concept album conceived by violinist Padma Newsome and guitarist Bryce Dessner. Simply put: It is a deep exploration of strings. They are bowed, struck, plucked, and treated as never before. The results are intimate, melodic, gorgeous. One moment they resonate like gentle raindrops, the next they're woven into dizzying eddies of sound. "Stick Music" is a bold achievement. It is odd and intense enough to satisfy avant-gardists yet -- after adjusting to Clogs' peculiar sound world -- it grows as accessible and comfortable as instrumental classics like John Coltrane's "A Love Supreme," Steve Reich's "Music for 18 Musicians," Ornette Coleman's "The Shape of Jazz to Come," or Brian Eno's early ambient works.