Listing all of the side projects associated with Chicago's Tortoise would take up the lion's share of this modest blurb, otherwise intended to sing the praises of a high-conceit art band that somehow found a way to make an instrumental stroll sound pretty dang engaging. How is it possible for a pair of rotating drummers and xylophonists to weave their way through guitar effects and a monster six-string-bass player (Doug McCombs from Brokeback) without dragging mud in the house? Much like the slow beast it's named after, Tortoise inches its way through a trance-like ambience, joining scraps of jazz, classical minimalism and avant-garde -- that is, when it's not dabbling in low-budget Italian film music, Kraut rock and assorted electronic weirdness. You'd think that navigating such a mess would make for bumpy sailing, but it's actually quite airy, atmospheric, beautiful and terrifying. And very good when experienced live. Touring in support of its fifth full-length, It's All Around You, Thrill Jockey's guiding light isn't the first to think of using the studio as an instrument, but its members deserve medals for dragging indie rock out of its own grandiose poop chute.