Pop: My, what a big lighting rig you've got

THE THING about Underworld is that they make repetitive electronic dance music that basically feels good and has a groove (not as easy as it sounds). They are also likeable - lovable, even. They project this likeability in a way that is larger than life on the Astoria's wide stage, in front of a matrix of five giant screens alternately showing abstract designs and closed-circuit TV images of the players.

Yet they do seem genuinely nice, your average guys-next-door, with pounds 30,000 worth of electronics but thoughtful enough to use headphones after 11pm without being asked. Your mother would like them.

What they do on stage is something like a recording studio mixing session turned into a performance. They all wear cordless headphones. Darren Emerson and Rick Smith operate faders and mute switches on a couple of mixers and Karl Hyde moves restlessly around the stage, sometimes twiddling what sounds like the filters of an analogue synthesiser, occasionally picking up a tambourine and, on one number, strapping on a type-decorated guitar.

It's Hyde's vocals, largely incomprehensible, repetitive yet compelling, that establish the rapport with the audience. He bends and crouches, side- on, radio mic in hand, with elegant/awkward gestures and contortions rippling around his skinny frame. When he isn't singing, which is most of the time, Hyde remains in the spotlight, sidling between the equipment manned by Smith and Emerson, making gestures of support to his colleagues or to the audience.

His stamina is enviable, but the Underworld show isn't really about the physical performance of songs. The show is a continuous two-hour audio- visual experience, based around repetition and electronic sound and four- square beats over which the five screens flash type and abstract images that sometimes complement and at other times contest the sound churning out.

The gargantuan rock'n'roll lighting rig, looking many times more expensive and sophisticated than the sound gear, has strobes, spotlights, rotating searchlights and blinding flashguns trained on the audience, building to the point where the (predominantly male) ticket-holders are brilliantly floodlit in time to the opening chords of "Born Slippy".

People dance or at least jiggle to their grooves, in a tradition of out- of-time English dancing that stretches back generations. Where the sampled kick drums go "duh, duh, duh, duh", the dancers seem to hear only "brnyah, brnyah, brnyah, brnyah". Underworld don't mind. They're nice guys, after all, and when you make repetitive electronic dance music, this is what happens.

On stage they are turning what was once a boring, unglamorous, non-real- time process - studio work - into a performance. That it succeeds as entertainment is mainly down to Hyde. You can't keep your eyes off his mercurial, campy manoeuvres. Their easy listenability is down to Smith's inventive production, and the trio's collective instinct for tasty sounds.

Underworld's repetitive electronic dance music dresses and undresses the skeletal structure of hard, explicit, four-four beats in a way that leaves their dope-smoking, lager-swilling - but basically quite nice - audience wanting more.