The best rock trios conjure a rare sort of magic. Each member has to pull his or her weight and, with nothing to hide behind, must know exactly what to play (and, just as important, what not to play). Austin’s White Denim does just that, specializing in smart, fragmented melody lines set to skittering rhythms. In the past, the band’s formula yielded both starkly fascinating grooves and, at times, a meandering, disjointed tangle. Yet on Fits (Downtown Music), the group is working the puzzle out. While no less schizophrenic stylistically, most songs here seem developed and purposeful. Slowed down, the sound can border on the folkish, but mostly the band rocks—furiously. The opening tracks set a relentless pace. Bassist Steve Terebecki and drummer Joshua Block lay down redlined, hard-driving foundations with abrupt changes, while guitarist/vocalist James Petralli dances over the top with brittle, chopped chording and a voice that ranges from a croon to a scream. Borrowing from the best—Cream, the Minutemen—they fearlessly roam from funk to blues to prog without ever losing their way.