At the start of Seventeen Evergreen's first UK headline show, a figure in black fiddles with a keyboard, unleashing what sounds like the forlorn call of a lost spaceship, then disappears. Popping up again, he adds another layer to the woozy sci-fi soundtrack, while onlookers watch, bemused.

Prompting head-scratching responses is what the San Francisco band do best. Born after hip-hop fan and Jack White lookalike Caleb Pate met wandering spirit Nephi Evans, Seventeen Everygreen's blissed-out space-funk churns with dark currents of Eno-inspired electro and postrock. Their debut album, Life Embarrasses Me On Planet Earth, poses questions about love and life in this universe and beyond, and sounds like a three-way battle between Pavement, My Bloody Valentine and the Borg.

But though there's plenty of confrontation, there are few sparks tonight. As instrumental opener Andromedan Dream Of An Octaroon gives way to the breezy Haven't Been Yourself Lately, Pate stares, dead-eyed. "This is pretty fun, so far," he says, deeply unimpressed. Blond and bearded Evans is equally apathetic.

But the less-than-dynamic duo can be bewitching. Sharing vocals and showing off their talents on everything from electric piano to electric glockenspiel - backed by bass, drums and keyboards - Evans and Pate soothe and agitate at will. Against Evans' low voice and acoustic guitar in Music Is the Wine, Pate adds seductive, high harmonies and a rhythm that morphs from gently melodic to shrill and distorted. Whimsical love song Constellation layers soft beats, the disco clapping sound much loved by 1980s remixers and yet more bitter guitar.

But it is Burn the Fruit, from their latest EP, that encapsulates their talents. After building up an old-skool dance tune, they take it in turns to tear it down. Evans attacks his glockenspiel like a boxer finishing off an opponent, Pate turns a playful Casio melody eye-wateringly sour, and jaws fall to the floor once more.