The Black Keys are hardly the first white boys to get a bad case of the blues. But whether you're talking Texas guitar wizard Steve Ray Vaughan, NYC hipster Jon Spencer, or newly minted millionaire Jack White, few white bluesmen have been willing to get as dirty as drummer Patrick Carney and singer-guitarist Dan Auerbach. Unsanitized and uncompromising, Rubber Factory finds the Akron, Ohio, duo wallowing in Mississippi Delta mud. The beauty of the Black Keys is their determination to keep things pure. From the Immortal Lee County Killers to the Kills, the post-White Stripes landscape has no shortage of duos working the blues-based angle. Auerbach and Carney stand apart because they have no interest in referencing backwoods country, greased-lightening rockabilly or Led Zep-indebted retro rock. As on their 2002 disc The Big Come Up and last year's Thickfreakness, this record serves its blues straight up, albeit with enough overamped distortion to stun a horse. What's different on Rubber Factory is that the Keys swing, especially on the gloriously grimy thumpers "Girl Is On My Mind" and "Just Couldn't Tie Me Down". More dramatically than ever before, Auerbach and Carney have also learned the importance of mixing it up; they slow things down to a molasses crawl on "The Lengths". But the two blues brothers are at their best when they kick it into overdrive, and nowhere do they do that more effectively than on the smashingly superfuzzed "10 A.M. Automatic". Every bit as badass as R.L. Burnside, the song doesn't sound like the work of two white boys from Ohio. And that's the Black Keys' greatest accomplishment. Somewhere south of the crossroads, a dirt-caked Robert Johnson is smiling.