ARRIVING at Dublin's Grand Canal Square, you could easily think you've blundered onto a recently vacated Dr Who set.

Strange red poles jut from the paving at odd angles -- when night descends, they start to glow and flicker, as if signalling to a waiting mothership.

It's the perfect backdrop for Liars, a downtown New York outfit who take indie rock's noisier conventions -- bleeding Sonic Youth guitars, shrieked vocals -- and drench them in art house weirdness.

Adding a human touch is beanpole frontman Angus Andrew.

As the rest of the group conjure swathes of anti-pop, he makes like a kindergarten Mick Jagger, wiggling his wiry frame and exhorting us to "have a party".

It's a bit like having Cliff Richard fronting Kraftwerk in their prime -- jarring but compelling.

Rather less inspiring are Danish post-rockers Efterklang, whose lumbering art rock goes to lengths to defy expectations and ends up sounding precious and contrived.

Taking the stage in flapping capes, knee-length trousers and neckerchiefs, the octet look like a bunch of 18th- century ne'er do wells. Alas, that's where the excitement ends.

Steeped in off-kilter grooves and hamstrung by seemingly random tempo changes, their songbook, though always straining towards moments of loveliness, seems determined to sabotage itself.

Frontman Casper Clausen is an engaging chap but, as the hubbub of conversation from the floor confirms, he's fighting a losing battle.

One of the innovators of the "post-rock" sound, Chicago's Tortoise makes no such primary errors.

Influenced as much by the boundary-pushing end of jazz as by avant-garde rock, the grizzled quintet takes a cudgel to the notion that experimental music should be icy or intimidating.

What sets them apart from other left-leaning sonic alchemists is the sweetness and empathy they imbue in their performance, not to mention a disarming lack of pretension: Led by drummers John McEntire and John Herndon they summon ebbing beats, strafed with dreamy drifts of guitar and vibrophone.

Throughout, there's an underlying cheerfulness which ensures that, no matter how strange things get, you'll want to keep listening.

- ED POWER