Timbaland Presents: Shock Value (Blackground/Interscope)

Not since Phil Spector has a songwriter/producer so profoundly shaped pop music as has Tim Mosley, whose space-age tracks set the template for rap and R&B as we know it. For all the hits he's authored, Timbaland has never been a pop star himself; instead, he's played the backstage genius, revered only by other artists and by obsessive types who study liner notes like scripture. That all changed in 2006, when the Virginian produced albums by Nelly Furtado and Justin Timberlake, planting his own face right next to his collaborators' and mounting a full-scale assault on the charts. Inspired (and likely irritated) by the singing and rapping forays of Pharrell Williams and Kanye West, Timbaland has become, for better or worse, a solo artist.

Timbaland Presents: Shock Value is actually his fifth album (including the three he made with also-ran rapper Magoo). Over its first half-dozen songs, the new disc far surpasses those earlier releases and in fact rivals some of the best material of his career, but at its worst (see his collaborations with the Hives, Elton John, and, um, Fallout Boy), the disc reveals a producer who's just plain run out of ideas–for now, at any rate.

Timbaland's voice only sounds good when he's interjecting it rhythmically at the end of other people's lines, so it's no surprise that his vocal turns here are anemic at best. That hardly matters when the arrangements are as dazzling as they are on, say, "The Way I Are", which marries rave-y synthesizers with the producer's inimitable stutter-funk. But when you hear him over by-the-numbers R&B (see "Fantasy" and "Scream") or cringe-worthy rap-rock ("Throw It On Me" and "One and Only"), you begin to understand why Phil Spector never bothered singing.