Knob-twistingly powerful

Regular readers will know that this column is often decorated with a concert photo, usually featuring a young man playing the guitar. The man has his eyes squeezed shut and his lips hauled back in a grimace, as if the instrument hanging from his neck weighed 400 pounds. What, you may ask, is he up to? The facial contortions are partly for show, partly a sign of concentration. To a large degree, they're plain old macho silliness. So I suppose that Tom Rowlands of the Chemical Brothers has just as much right to pull faces, even when he is doing nothing more taxing than twisting a knob on a mixing desk. And maybe his pained expressions are just reminders that the chemicals combined by him and Brother Ed Simons are techno and rock'n'roll.

The most obvious traces of the duo's rock element are the vocals of Noel Gallagher on one track, and of the Charlatans' Tim Burgess on another. Less superficially, the Brothers go to considerable lengths to make their machines sound like an expert, muscular drummer, and to instil their music with enough raw energy to distract the dancephobic guitarphiliac from his Oasis CDs. Certainly, with the furious, stroboscopic funk of their number-one single, "Block Rockin' Beats", the Bros make a powerful case for being the future of rock'n'roll. But I'm not so sure that they're the present - simply because Dig Your Own Hole (Virgin), worshipped in some parts as the record of the decade, is almost entirely free of tunes or lyrics, and so cannot sustain the browser's interest from start to finish.

Still, a quick count of T-shirt logos at the Cardiff University Students' Union on Wednesday confirmed that there were more indie kids than clubbers present, and they had no complaints. The ferocious "Leaving Home" set the exhilarating tone, as a barrage of breakbeats punched holes in layers of sound effects: Space Invader blips, divebombing screeches, and, on "It Doesn't Matter", what can only be described as the neighing of a robotic horse.

Amid this aural firework display, the two boffins did some serious gurning, agonised by the physical exertion of twiddling some knobs. In true rock- band-style, they incorporated even the dreaded pre-planned "encore". But if, then, we are to judge the show as a rock gig, it loses its way after 40 minutes, when the incessant beats become redolent of a Led Zeppelin concert's endless drum solo. As brain-bashing dance music, however, it was more or less unmatched. So remember: don't bother watching the chaps on stage. They may break the eggs with a flourish, but you wouldn't keep your eyes on the chefs all evening when you could be savouring your meal.

Death in Vegas are more of a "real" band. Opening for the Bros in Cardiff, Steve Hellier and Richard Fearless (presumably named after the hero of a black-and-white sci-fi serial) had brought along a bassist, guitarist, organist and a singer. But as long as they were playing Little Axe-style blues-reggae, the half-full hall wasn't interested. Death in Vegas were dying.

Resuscitation came in the form of "Dirt", a bombardment of dance beats and big, jagged guitar chords. In other words, the crowd preferred Death in Vegas when they sounded like the Chemical Brothers, and the apologetic set did scant justice to the band's wonderfully eclectic debut album. Death in Vegas really come alive on Dead Elvis (Concrete), not in their live shows. And if you could follow that last sentence, reward yourself with a copy of the record.

At the Cambridge Junction last Sunday, Huey, the mononymed, goateed singer/guitarist of the Fun Lovin' Criminals, twanged a snippet of Aerosmith's "Walk This Way", before stopping himself short. "I gotta pay 'em 20 dollars to play that riff," he joked, sounding as much like a young Robert De Niro as he looked. Or maybe he wasn't joking. Quentin Tarantino charged heavily for the snatches of his dialogue they used on their hit single, "Scooby Snacks", so the FLC have reason to be careful. On the other hand, the trio owe more than $20 to Steve Tyler's gang of geriatric drag queens. We all do. It's the fusion of rap and rock first essayed by Aerosmith and Run DMC that is saving American music from slacker hell.

The Criminals don't glue together heavy metal and rap, though. Rather, the sharp-dressed goodfellas put a funky beat to every genre you'll hear booming from an apartment window if you walk down a New York street. Huey starts "Bombin' the L" by crunching half of a Deep Purple riff, but a few songs later, he is growling "We Have All the Time in the World", and adding blues and country to the melting pot with a few bent notes of his semi-acoustic. And didn't Fast, his multi-instrumentalist compadre, get the sleazy trumpet line on "King of New York" from Also Sprach Zarathustra?

In concert, the band are grungier than they are on their first album, last year's universally acclaimed Come Find Yourself (Chryalis), but they don't sacrifice their laidback vibe. Huey mutters his New York stories hoarsely and sleepily, too cool to raise his voice. The Criminals are so busy being cool, in fact, that they don't have time to boast about it, which is the difference between them and most American rappers. Snoop and Coolio tend to palm off their audiences with obnoxious exercises in self-satisfied self aggrandisement, whereas the more humorous FLC see themselves as having stepped out of Mean Streets or Pulp Fiction, or possibly even Bugsy Malone: they like the idea of being gangsters before the "er" was replaced by an "a".

Stylish, charming and undeniably fun-loving, Huey grinned his way through his solos as if he'd never played the guitar before, and he was elated by how well it was going. The main reason why this was one of the most riotously entertaining gigs of the year so far is that the band seemed to think it was, too.

Chemical Brothers: Leicester De Montfort Univ (0116 255 5576), Tues; Glasgow Barrowlands (0141 339 8383), Wed; Newcastle Univ, (0191 261 2606), Thurs; Birmingham Que Club (0121 643 6103), Fri; Sheffield Univ (0114 222 8777), Sat.