In 1950, as the blues, gospel and jazz cross-pollinated but before Detroit's Motown, before Memphis' Sun and Stax - and well before Philadelphia International Records - there was Chicago's Chess label. Those of a certain age fondly remember its logo, a silhouette of a king chess piece flanked by those of bishop and knight.

Cadillac Records, Darnell Martin's boisterous, if not always factual, account of the house that Muddy Waters, Howling Wolf, Chuck Berry and Etta James built, is a variety show of the personalities and music that spawned the urbanization of the blues and midwifed the birth of rock-and-roll.

Martin, who made her film debut in 1994 with the raucously funny I Like It Like That, wrote and directed this ensemble drama with music and narrative enough for five features. In this crowded film that lacks a defining central character, all the actors, however dominant or subsidiary, deliver star turns. This is not necessarily a good thing.

Martin's movie chronicles a transformational moment in popular music and culture. Before being eclipsed by the other performers, Jeffrey Wright registers powerfully as bluesman Muddy Waters, Mos' Def duckwalks as country-to-rock crossover dream Chuck Berry, and Beyoncé wails her heart out as soul singer Etta James.

But among these scene-stealing headliners (who include Adrien Brody as the label's "ears," Leonard Chess), the knockout is Eamonn Walker, positively feral as blues sensation Howlin' Wolf. (Martin previously worked with him on the hard-hitting behind-bars TV series, Oz.)

Musician-songwriter Willie Dixon (affable Cedric the Entertainer) provides the narration quilting together the story that spans 1941 to 1969, from Muddy Waters migrating to Chicago from Mississippi to Leonard Chess' sale of the label to his artists.

(In the interest of narrative pruning, Martin entirely eliminated Philip Chess, Leonard's brother and partner, from the story.)

The real-life Chess was a contradictory and complicated figure, not unlike Jamie Foxx's Curtis Taylor of Dreamgirls, suggested by Motown's Berry Gordy.

Dreamgirls was critical of Curtis' shady deals and artistic backstabbing. But Cadillac Records (which takes its name from Chess' habit of buying his artists fancy cars with their royalties instead of giving them the money outright) is mystifyingly neutral about Chess, who bribed disc jockeys and cooked the books.

Brody plays Chess as a slightly crooked but well-meaning musical cheerleader without fully emerging as a character.

Cadillac Records is a toe-tapping experience where the music rather than the actors dominate. This undermines Wright's performance and advantages that of Beyoncé. The film boasts a soundtrack that includes the actors performing Muddy Water's "Mannish Boy," Howling Wolf's "Smoke Stack Lightning," Chuck Berry's "Sweet Little Sixteen," and Etta James' "At Last."

As the legendary James, beset by drama and drug addiction, Beyoncé delivers - if more powerfully as actress than as a soul thrush. (I would have cast Queen Latifah, whose voice has more edges and corners, but then, I would cast her in just about anything.)

As drama, Cadillac is adequate. As a jukebox musical, it soars.

Cadillac Records **1/2 (out of four stars)

Written and directed by Darnell Martin. With Jeffrey Wright, Adrien Brody, Beyoncé, Eamonn Walker amd Mos' Def. Distributed by Sony Pictures.

Running time: 1 hour, 48 mins.

Parent's guide: R (profanity, drugs, sexuality)

Playing at: area theaters