Most of Tusk sounds like Frank Zappa’s chamber music. It’s got favorite Zappa instruments (guitar, clarinet, vibraphone and drums); atonal, gnarled compositions; and blinding speed and staccato percussion. Sean Moran’s acoustic guitar style even uncannily resembles Zappa’s. Oddly, for all its speedy runs (mostly on Chris Dingman’s vibes), it’s moody, slow-paced-even trudging-stuff. It’s also infrequently compelling, sometimes within a single tune: The tricky triple meters of “Monkeytown” have much more spark than Moran and clarinetist Michael McGinnis’ lines. Indeed, melody is often the album’s hurdle; “Elliptical” or “The Camel” make sudden, swooping shifts in melody and harmony that might excite academics but offer no foothold for lay listeners. Taken from the whole, individual players succeed here, particularly bassist Reuben Radding, with his thudding pulse (“The Camel”) and eerie arco (“Circle One, Two”). And a few pieces, like “Ten Mirrors,” are intriguing in their way.