N.E.R.D.

Pharrell Williams and Chad Hugo, aka the Neptunes, are nothing if not ambitious. Their production techniques rule pop radio, but they hunger for success that not only crosses genre lines, but obliterates them. Hence, N.E.R.D., in which Williams, Hugo and cohort Shae attempt to reach the rock audience without alienating the R&B and hip-hop camps. Fly or Die doesn't quite turn this trick, but at least the group, which headlines the Fillmore Auditorium on Sunday, April 4, with Black Eyed Peas and the Clipse, goes about its business in a singularly twisted way.

Among the guest stars on Die are Lenny Kravitz, who pokes his usual retro shtick into "Maybe," and Good Charlotte's Joel and Benji Madden, recruited to croon on the jaunty adolescent curio "Jump." In the end, though, star power is less important than coherence -- a quality most of these tracks lack. Take the title cut, which features glam guitar, quirky keyboards and shouts of "This is for the kids!" and "Oh, God!" The result is less a song than a collection of wacky musical elements stuck together with the studio equivalent of Krazy Glue.

Fortunately, these guys are talented enough to make self-indulgence intermittently entertaining. "She Wants to Move," the first single, is a perky mess that employs both hand claps and dog barks, not to mention the sci-fi sound effects heard after Williams declares, "Her ass is a spaceship I want to ride."

Strap in, because it's gonna be a bumpy flight.