Liars, ULU, London <!-- none onestar twostar threestar fourstar fivestar -->

At a time when rock is regularly written off as exhausted, it's worth noting the growing audiences currently turning out for music which, in most contexts and previous decades, would be considered uncompromisingly avant-garde. It's in this desire for new, complicated sounds that that the much-mooted post-punk revival has really bloomed, not in the replication of old Gang of Four riffs which some bands have settled for.

Liars are a wonderful case in point. They were formed in Brooklyn, and their debut, They Threw Us All in a Trench and Threw a Mountain on Top (2001), seemed a perfect fit with the area's punk-punk scene, borrowing copiously from Gang of Four's scratchy guitar manual. But they moved on before the world's embrace of post-punk could catch up with them. By the time of their current, third album, Drum's Not Dead, their Australian singer, Angus Andrew, had led the others to Berlin, searching for feelings of dislocation and loss, and creating a sprawling, fluid, multimedia concept piece about certainty and fear. And, judging by tonight's freeform gig, such wilful ignoring of industry expectation is giving a good part of the public exactly what they want.

Andrew, tall and bearded with a straggly mane, is an arresting proposition. His slurred, yobbish vocals kick off "Youth Invasion", while fellow Liars Aaron Hemphill and Julian Gross crouch over tribal drums. But it's not until "We Fenced All the Gardens" that he reveals his performing essence, as he whips off his jacket and marches across the stage, shrieking and striking shamanic poses. He recalls Nick Cave, by way of Jim Morrison, but with a hovering sense of humour.

The shamanic intentions are real, though. For "Hold Hands and It Will Happen", a low electronic hum of primordial roars and hisses and soft, galloping drums are all that can be heard at first. Then as the sound and tension thicken, the music gently loosens its moorings, and steadily builds in effect. Andrew has adopted a dead-eyed zombie strut, and the overall feel is of a very altered state, a ritualistic, open-ended musical sensation you don't experience often. It's post-hippie more than post-punk, both trippy and tribal.

It can't be denied that a closing, screaming cover of Nirvana's "Territorial Pissings", with its drive, melody and history, gets the biggest response from the crowd. But they listened to the rest, encouragingly open-minded and engrossed.