Tortoise

You might think of Tortoise as a place where Chicago’s vibrant improv, jazz and out-music scenes flowed into indie and punk aesthetics. Since 1990, the group has been churning out instrumental music that moves in jags of cerebral energy. But that would only account for a portion of the multi-faceted ensemble’s endeavors. Their compositions for rock instruments and electronic interventions also soak up impressions of dub, techno, modernist music, Krautrock and prog. The group was founded by a rhythm section, Doug McCombs and John Herndon (a native of Ashville, NC), so naturally, muscular cadences give heft to Tortoise’s most alien-sounding soft-jazz numbers. With the quick addition of several more members (including another percussionist, John McEntire), they locked on a rock configuration malleable enough to truly earn the designation “post-rock.”

Hardly anyone else could keep up. “Post-rock” quickly became shorthand for the noodly, incandescent guitar workouts typified by Explosions in the Sky. But 20 years on, Tortoise still pushes against the borders of what rock music can be, although they’ve settled into a rarified style. Their albums arrive at a distance of years, and each seems to mark a period of covert, deliberate work. Their latest, 2009’s Beacons of Ancestorship, found them bouncing back ferociously from a tepid 2004 effort, It’s All Around You. On Beacons, they interpret strains of dance music more energetically than ever. “High Class Slim Came Floatin’ In” breaks up the swoops of rave music into clipped, towering movements. “Northern Something” is blown out French house music gone all a-squiggle. They toy with progressive synth music and minimal techno, surging up in blown-out punk anthems (“Penumbra”), downshifting into spacey film music (“The Fall of Seven Diamonds Plus One”). Given the band’s long work cycle, it’s likely they’ll still be playing some of these songs, which is great—in the live setting, Tortoise’s subtleties are deeper, their explosions louder. Yell loud for “Northern Something.”—Brian Howe