The Black Eyed Peas, Academy Birmingham

Nearly three years ago, The Black Eyed Peas played Birmingham Academy 2, in front of a few hundred hardcore hip-hoppers. Now, these Los Angeles rappers are launching a mini-tour to capitalise on their unexpected chart-topping successes, and the main Academy is sold out, full to bursting.

It was better back then, when we could see the posse, could witness their agile gyrations, their witty body-language. Now, it's a strain to catch the odd bobbing head, and the sound quality is muddied, dull and bass-heavy.

The Peas take the trouble to tour with a real band. Drums, guitars, keyboards, saxophone, trumpet. But when they first hit the stage, delayed to the point of riling an unruly crowd, the speakers are blurting out a distorted mash that could be coming out of a cheap radio. Their songs aren't projecting very far...

The current Elephunk album rejoices in an adventurous production style, full of genre graftings and sonic surprises. The live spread is more conventional. As the Black Eyed set progresses, the mix becomes clarified and the front-line foursome start to gather and channel a sense of hysteria. Certainly, the mass of new fans are shouting, screaming, jumping and waving their hands in the air, in a way that we don't usually see at gigs in these jaded days.

Since their Bridging the Gap album, the original trio of Will.I.Am, Apl.De.Ap and Taboo have been joined by Fergie, who provides soulful singing, designed to pull in a wider audience. Her voice cuts through powerfully, and she fits in well with the gambolling on-stage tomfoolery. Fergie's impressive range is demonstrated to almost comic effect at one stage, booming down low into her gut before shrieking tune- fully up to the heavens. Apparently, she met Will.I.Am by chance and was invited to a recording session, but her induction seems suspiciously like a record-company request to open up the Pea appeal.

The Black Eyed ones are still wired-up rappers, but their music has now colonised other zones. The best new tunes are the ones that owe a debt to Funkadelic, the gig starting to rise up with the ridiculous "Let's Get Retarded" and "Labor Day (It's a Holiday)", its central James Brown sample reproduced by real-life saxophone.

Numbers such as "Shut Up" and "Latin Girls" present even more obvious opportunities for direct fun, but when the Peas return for their first encore, the band gets to deliver extended guitar, saxophone and trumpet solos, displaying their jazz chops. This is a subversive activity, following the singalong antics of "Where Is the Love?", which is, incidentally, the album's worst number. The crowd were well in tune, joining in with impressive gusto.

The Black Eyed Peas have now removed themselves from the hip-hop underground, but they've still managed to retain their musical integrity, inviting a more mainstream audience to hear what is still hard-edged rhyming, and developing a new fascination for the history of funk. Their strategy of freestyling a lengthy Birmingham tribute is obvious but still effective, name-checking the city at regular intervals. They'll be giving London the same treatment on 3 March, at Brixton Academy.