Joy Zipper, 100 Club, London

The record industry has kicked Joy Zipper in the teeth so often, it's a wonder they're still capable of standing on a stage.

The record industry has kicked Joy Zipper in the teeth so often, it's a wonder they're still capable of standing on a stage. Their second album, American Whip, was recently released to great acclaim - the same rave reviews it got more than a year earlier, until its release was pulled by an ailing Ministry of Sound. American Whip was itself the product of two years of limbo, when the band - essentially the couple Vinny Cafiso and Tabitha Tindale - retreated to Cafiso's aunt's basement in suburban Long Island, after another record label went bust.

The cultural deprivation was their making: American Whip overcompensates with almost overwhelmingly lush arrangements, sickly sweet, beautiful music in thrall to the 1970s, but secreting lyrics about senility and suicide. It is Californian-style pop with the sonic density of dance music. Although much has been made of the darkness in their lyrics, it is really their rare brightness that makes Joy Zipper alluring.

The genuine, if troubled, innocence of Cafiso and Tindale is the source of these seeming contradictions, which they tease out in a subtly compelling, unpredictable show. She leans over her keyboard, face in shadow, eyes shut; he shoulders his guitar like he is living in a 1960s TV clip, gawky and eager. Both look younger than their 30 years and banter awkwardly between songs, as if being on stage is a nervous novelty.

The sound they make is thick like treacle, their four-piece band just big enough to replicate the record. But in this small basement club, the blissfully intense harmonies and sampled string-banks of even their best song, "I Dozed and Became Invisible", are indistinct in their effect. Though Joy Zipper's voices redouble and loop in layers, and guitar chords climb and grow, the relentless grandeur is almost numbing. They seem more suited to a concert hall or a super-club, to sonic precision or overload. Here, thunderous chatter from the bar counters the cheers of loyalists. Even an eerie version of "Alzheimer's", every word slowed as if squeezed from an afflicted mind, doesn't wholly connect.

Still, Cafiso and Tindale's endearing pleasure at being on any stage, despite all their setbacks, keeps me watching. And a reward for all of us comes right at the end, when the club's curfew denies Joy Zipper an encore. The lights go up, but the crowd don't leave, and Cafiso comes back with an acoustic guitar and pleads with the management to continue. And though the stripped version of "Valley Stream" which follows destroys the point of Joy Zipper's dense music, it reveals the flaky charm of the couple behind it. As Cafiso stretches the chorus to breaking point, Tindale leads a clapping singalong. Only the Geiger-counter click of the microphone she points at us reminds you how dark Joy Zipper's sunniness can be.