Savion Glover, Sadler's Wells, London

The man behind the moves in 'Happy Feet' makes his own music in a display of deafening virtuosity

Once, you had a clear idea of what to expect from tap. Rhythm, it goes without saying, but also glamour, a certain pizzazz, an eagerness to please.

Ginger Rogers and Fred Astaire gave the form a sweeping ballroom quality. Gene Kelly made it fit with a gym-worked six-pack. Ranks of identical Berkeley girls hopped and clattered and shuffled in synch to sauce up an entire generation of musical films. And that was pretty much the image that stuck.

So what to make of Savion Glover, the New Jersey hoofer who comes on stage in loose trousers, clumpy boots, full beard and a hairdo that resembles a basket of snakes? Mounting a low box, without a note of introduction, musical or otherwise, Glover simply gets on with what he does, which is to make rhythm with his feet – nothing more and nothing less. The title of the show says it all: Bare Soundz.

Crouching slightly, arms held loosely at his sides – more for balance than style – he launches into a Chattanooga chug, like a train under full steam. Every eight bars the rhythm changes, but the dynamic remains the same: loud, insistent, battering. And Glover isn't alone. Two colleagues, similarly dressed as management types meeting in the Country Club after hours, rattle alongside on their own miked-up boxes. The synchronisation is stupendous: you could be hearing one set of feet. But otherwise the appeal is esoteric. This show doesn't attempt to work as theatre. It's dance for the ears, not the eyes.

As viewers of Strictly will know, the first thing you're ever taught is not to look at your feet. Glover throws that out of the window. He spends half the time looking down, and a good deal of the rest with his back turned, egging on his colleagues. Both Marshall Davis Jr and Maurice Chestnut are more than competent technicians, but they're not star material, not what this crowd has come to see.

Glover has terrific pedigree. A protégé of the late Gregory Hines, the man who put tap back on the map in America, he made his Broadway debut aged 10, has a string of Broadway credits, provided the moves for the dancing penguin in the animation Happy Feet, and has been hailed as the greatest tap dancer alive. He is also a fervent genealogist. His Broadway creation, Bring in Da Noise, Bring in Da Funk, explored tap's history as an amalgam of Irish step, Lancashire clog and West African clapping dances, and updated it all as hip hop.

And now here he is, making no concessions to a British audience who missed out on the Tony award-winning history lesson. It's a tough initiation. The named numbers in the programme booklet could be a guide, but it's not easy to tell where "B Bop Bird" ends and "Mr Calypsonian" begins. I like to think I could detect the African-tinged riffs. They were the irregular ones a musicologist would have trouble writing down. But beyond that the grooves, whether jazz or hip hop based, or drilled like flamenco, tend to blur into one. The visual sameyness and unvarying fortissimo don't help.

There is relief, though. The seamless baton-passing of "Trading Places", as one hoofer hops up to the box as the other hops off. The miraculous way Glover distributes beats and backing between heel and toe, left foot and right. And the joyous moments, often signalling the close of a number, when he jumps in the air, waggles his legs and skips a beat. Ah, silence! Bliss.