When the leader of a band departs to go solo the group usually crumbles, but in Tristeza’s case the remaining members formed a better band. By the end of 2003 front man James LaValle had decided to go full-time with his band the Album Leaf; drummer James Lehner and keyboardist Stephen Swesey were gone as well. Guitarist Christopher Sprague and bassist Luis Hermosillo were left to rebuild, and on the evidence of the new A Colores (Better Looking), they’ve saved Tristeza from continuing on as a phenomenally boring Tortoise rip-off. The new lineup, now coed with the addition of guitarist Alison Ables, sticks to the band’s familiar template of delicate keyboard figures and arpeggiated guitar mantras, but the playing’s livelier and the songs have more depth and detail. “Halo Heads” is prime work, evolving over the course of five minutes from a micromeditation to a warping, expansive riff that chases its own tail before it’s almost swallowed by a sudden swath of reverb. The Promise Ring headlines and Make Believe plays second. This show is part of Flower 15; for a complete schedule see page 38. Sat 11/12, 6:30 PM, Metro, 3730 N. Clark, 773-549-0203 or 312-559-1212, sold out. All ages.