For this self-released instrumental EP, Sonic Youth teamed up with Jim O'Rourke, the avant-garde/post-rock guru best known as a member of Gastr del Sol. While the collaboration is a little long-winded -- the "EP" lasts nearly an hour -- and is the most difficult of the first three SYR recordings, it also provides some of the best music of the series. It just takes a little digging to find it. SYR 3 is closer to Gastr del Sol, in many ways, than Sonic Youth, but that's refreshing. All the members of SY switch instruments on the record, and O'Rourke pushes them into free jazz territory. Occasionally, they can get lost in the murk, drifting into long static stretches that barely rise above a murmur. More often, though, the music is fascinating, with the subtle layers and seamless transitions becoming mesmerizing. It takes a little work to get into SYR 3 -- a recording that is more complex and ambitious than its full-length follow-up, A Thousand Leaves -- but the cerebral, difficult music is worth the effort.