Various Artists: Cadillac Records Original Movie Soundtrack

The theory behind projects like the 2008 film Cadillac Records is a simple, double-sided one: get 21st-century favorites to take on Fifties rock and blues, and you'll make converts of new fans while making tired old standards fresh again. In this case, Beyonce plays Etta James, Mos Def is Chuck Berry, and other recent R&B stars attempt the classic cuts of the history-making Chess Records. But a project like this is arguably too far removed from its time to recapture it fully, and the attempts at updating this music for new generations are tentative and stilted. It's a worthy concept, that is, just not a necessary one.

A soundtrack like Cadillac Records is always a dubious proposition, but one that works best when its artists have been around long enough for the retro stuff to have been a living, breathing part of their childhood. Meaning that it would be much easier to turn Beyonce into Diana Ross than Etta James, or for rapper Mos Def to take on Rick James than Chuck Berry. Still, this CD gives it a game try, produced by roots master and session legend Steve Jordan and overseen by Marshall Chess, scion of the legendary family that started the label.

Would that it were enough. Beyonce sings Etta like a diva -- technically proficient, but overemoted and lacking every bit of Etta's sly subtext and hard-won earthiness. Beyonce knows how to sing the blues, in other words; she just doesn't know how to have them. As for Mos Def, he's proven himself as an actor, but he bears no vocal similarity to Berry whatsoever, making it hard for neophytes to understand Berry's winking, witty appeal. The big surprise is actor Jeffrey Wright, James Bond's CIA buddy in his latest films, who gets very close indeed to the classic Muddy Waters vocal and musical sound.

When these three aren't on, however, the soundtrack loses all direction: the new songs work well enough as Dreamgirls-like updates of '60s soul moves (historically wrong, but refreshing), the gaps are filled up with old Little Walter hits and covers of same (Elvis?!), until the OST finally throws up its hands entirely and falls back on rap hits from the past few years that sample Chess Records' output. (The deluxe version of the album merely repeats the formula over a second disc.) Wright would do well with his own blues album; as for the rest of you, you're better off picking up Chess' own attempt to cash in on the movie, a comp entitled The Best Of Chess Records that lets you really feel the music, not just learn it.