It's a sure sign that a band is going to be loud when the floor starts shaking as soon as they turn on the amplifiers. Before Comets on Fire have even begun, the ICA is trembling underfoot from the feedback, and when the band do explode into life it's a gigantic, deafening joy.

Comets on Fire's brand of arty, psychedelic rock is going through a purple patch in the US, but these stormy Californians seem to have the creative edge. Their recent albums (including this year's superb Avatar) are full of soulful, jazzy subtleties that lift them way beyond the norm, and the power of their delivery tonight makes it all the more exciting.

The extra noise and speed with which the songs are attacked removes some of the precision - things get downright free-form at times. Ethan Miller and Ben Chasny's guitars often break into lengthy, abstract wailings, while the five scruffy silhouettes flail around behind the strobes and dry ice. It is an overwhelming spectacle that comes close to achieving the ultimate way-out rock sound.

But equally great things happen when they ease off the volume. Jaybird revolves around a slinky guitar line that could almost be Cream or the Band of Gypsies, and the epic instrumental, Sour Smoke, moves through passages of delicate riffing with effective restraint. And, although the emphasis seems to be on sonic exploration rather than songwriting, Lucifer's Memory puts Miller's vocal upfront in a classy soul ballad that is the most melodic moment all night, and a great example of how far they can stretch their style.

Another spacey, psychedelic meltdown closes the set, and as the lights come up, the audience stumbles out, grinning. As an example of pure power matched by creative sophistication, tonight will be hard to beat.

· At Black Box, Belfast, tonight. Box office: 02890 244400. Then touring.