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Bjork enlists the help of many guests on "Volta," including pop beatmaster Timbaland, who adds unpredictable sonic textures. (Frank Franklin II/Associated Press)

Bjork has the beat, but lacks a vision

After dedicating her previous album, 2004's "Medulla," to the glories of the unadorned human voice, Bjork has turned her new one, "Volta," over to the wonders of percussion, with similarly mixed results.

The Icelandic chanteuse has found a new playmate in Hall of Fame beatmaster Timbaland, whose work with artists such as Missy Elliott and Justin Timberlake shows a shared interest in unpredictable sonic textures. Timbaland twiddles knobs on some of the most successful tracks on "Volta," which comes out today: album opener "Earth Intruders," which mingles video-game noises and an industrial beat with ghostly howls and an off-kilter stab of keyboards; "Innocence," on which Timbaland channels his predecessor the RZA, with chop-sockey kung-fu sounds, pounding drums, and the Wu-Tang master's out-of-tune instrumentation.

But "Volta," much like "Medulla," is an appealing series of collaborations and musical ideas that do not quite jell in their final, recorded versions. In part, that can be blamed on the music, which lacks the future-forward sheen of earlier efforts such as "Post" and "Vespertine." "Volta" also lacks the consistency that marks Bjork's best work. At her strongest, Bjork turns over an entire album to a single idea, and a single sound.

As a musical generalist, Bjork feeds off the work of her co-conspirators, taking their highly specialized work and rendering it unmistakably her own. Past Bjork accomplices such as Tricky, Eumir Deodato, and Marius de Vries formed inspired templates for music both fresh and recognizably Bjork-esque. But on "Volta," the sheer bulk of guests (who include, in addition to Timbaland, Antony Hegarty , Konono No. 1, and a 10-piece Icelandic brass band) overwhelms any attempts at cohesion. Here, that magical mind meld is just not happening.

The content of the album's songs is similarly unfocused. "Earth Intruders" takes comfort in the troubling notion of violence as a solution to social and world problems, imagining "Metallic carnage! Ferocity!" The protagonist of "Hope" is a (possibly) pregnant suicide bomber on the way to meet her target. Like any musician educated in the school of punk rock, Bjork (who goes electro-punk for the pounding "Declare Independence") finds a source of creativity in destruction. These references, however, touch uncomfortably close to contemporary horrors, in a way that is more disconcerting than pointed. In interviews, Bjork has said the songs stem from her feelings about the Bush administration, but that's impossible to tell from listening to them.

She is far better off when singing with specificity, to her teenage son on "My Juvenile," for example, or piercing the staccato horns of "Wanderlust" with her own declaration of ceaseless adventurism: "Wanderlust, relentlessly craving wanderlust. Peel off the layers until you get to the core." "Declare Independence" even offers a starter's kit for the journey: "Start your own currency, make your own stamp, protect your language."

True as ever to those tenets, Bjork looks to find herself by journeying the world in search of sound. That search is an honorable one, but she must not forget that all travels must come to an end, and that discoveries are most valuable when you can share them with others.