"When you come see N.E.R.D.," Pharrell Williams was saying from the stage of the Paradise last week, "you can’t forget, like, it’s the Neptunes! We make beats! We want you to hear the new shit!" It was a good bet that no one in the packed house had forgotten that while they were all ostensibly present to see a rock band called N.E.R.D., they were also seeing the men who, as a production team called the Neptunes, have created one of contemporary pop radio’s most distinctive hit-making sounds: minimalist, futurist, fractured, funky.

Indeed, N.E.R.D. (which stands for No one Ever Really Dies) began as a receptacle for tracks that Williams and his partner Chad Hugo hadn’t been able to place with their regular clients, such hip-hop titans as Jay-Z, Mystikal, and Busta Rhymes, as well as pop megastars Britney Spears, ’N Sync, and the Backstreet Boys. But having recorded their album in the ultra-synthetic style of pop and hip-hop, N.E.R.D. suddenly had a change of heart and, a few weeks before the disc’s scheduled release, enlisted a funk-rock band called Spy Mob to help them re-record the entire album with guitars, drums, and bass. At a time when rock is trying desperately to emulate the hip-hop and pop sounds in which the Neptunes specialize, N.E.R.D.’s about-face was, at the very least, puzzling — like that time Michael Jordan decided he wanted to play baseball.

The Neptunes’ sound relies on studio trickery: hip-hop producers are students of the science of sound, able to tweak specific frequencies and customize the texture of keyboard loops like molecular biologists tinkering with DNA. It seemed far-fetched to expect a rock band to replicate crinkled beats and saturated bleeps, but at the Paradise, Spy Mob — four clean-cut white guys — functioned like a highly disciplined portable sound lab: the drummer sat out on all the right beats, the keyboardist performed a remarkable impression of the Neptunes’ signature bloops, and no one overplayed. They even handled an encore medley of Neptunes hits, including Busta Rhymes’s new "Pass the Courvoisier."

Seconded by an MC called Shay, Pharrell Williams made up in charisma what he lacked in technical ability. (Hugo, the shy Neptune, didn’t appear to be present). "Brain" came off as a mutant hybrid of David Bowie and Cameo, with Williams singing the title hook in the exact distended way Bowie sings the word "Fame." "Things Are Getting Better" and the ’60s-garage-poppish "Baby Doll" required some slightly off-key soul singing (a Neptunes trademark since Ol’ Dirty Bastard’s Nigga Please), and Pharrell obliged. The R&B diva Kelis, a Neptunes favorite, provided a mid-set reprise of her guest role on "Truth or Dare," along with the single ("Popular Thug") and the title track from her forthcoming Wanderland. The white rapper Lee Harvey reprised his verse on "Lapdance," a propulsive strip-club anthem with political overtones and a baritone surf-guitar lick that very nearly started a mosh pit.

But the high point was N.E.R.D.’s latest single. In "Rock Star," Williams and Sway shouted down "fucking poseurs" and the chorus clicked from a few spare bleeps to a stuttering crush of guitar; meanwhile Williams delivered the verses in a voice that unmistakably mimicked rock star Jonathan Davis, whose heavy-metal band Korn became famous by adopting some of hip-hop’s sonic tendencies. If there is a signature moment of 2002, perhaps this was it: a hip-hop producer imitating a rock singer while fronting a rock band replicating a hip-hop record. If it didn’t amount to reparations, it was at the very least a poetic revenge of N.E.R.D.