“When young white kids play black music, it turns into rock ‘n’ roll,” says Luther Dickinson, singer/guitarist of the North Mississippi Allstars. He makes one more in the long line of white rock musicians to put forward that assessment. Whether it’s an accurate one (Eric Clapton and John Mayall would probably have words to say on the subject), brothers Luther and Cody Dickinson and their bassist Chris Chew have certainly made that the band’s guiding philosophy.

The blurred, dusty blues and roots music produced by the Dickinson brothers over the past three years lives somewhere in the space between R.L. Burnside and Black Sabbath. Sometimes they wail, sometimes they whisper. Their songs alternate between grit and fluidity, while their style wanders between traditionalism and a claustrophobic blues-punk fusion.

51 Phantom, the North Mississippi AllStars’ second album, grounds itself in rock territory, with nine original compositions and only two covers. Until now, the group has found its bread and butter in reworking country blues standards from a rootsy, jam-rock angle. Luther and company twisted the rustic blues of fellow Mississippian Fred McDowell into droning punk jams and transformed Junior Kimbrough’s rickety songs into funky stutters. They achieved unlikely success (most jam blues makes me long for a coma-inducing traffic accident), as the Recording Academy folks nominated their first LP, Shake Hands With Shorty, for Best Contemporary Blues Recording in 2000.

On their latest release, the Dickinsons make a whole-hearted attempt to write from and expand upon their own roots, and they deliver. But the product alternates between sublime, innovative fusion and boring fuzz-rock exercises. At the high moments, Luther’s gravelly voice scrapes out melody over the distorted buzz of his lead guitar. Chris Chew holds down the low end, while Cody Dickinson keeps his drums consistently equalized near the middle of the mix. Legendary producer (and father) Jim Dickinson supervised the production of 51 Phantom, and he helps the North Mississippi AllStars’ rhythm section emulate the jug bands and juke-joint washboards of hill country roots music.

But while Chris and Cody’s interplay will sometimes kick a song into high gear (“Sugartown” and “Freedom Highway”), their workmanlike approach often leaves Luther’s sparse songwriting stranded in ZZ Top-land. Similarly, Luther’s voice has the capacity for sweet murmur, but it also will artlessly saw its way through an entire song.

With repeated listens, I was surprised to find that the ballads held up better than the other material. “Leavin'” is the essence of relaxed, unencumbered songwriting. It’s got a hummable melody and an infectious three-chord bluegrass structure that makes you want leave it on repeat. It also sets the down-home tone by quoting both W.C. Handy and Blind Lemon Jefferson in the first line: “When that evenin’ sun go down/ I’m bound to leave you baby, and ramble on.”

Blues, rock ‘n’ roll, and punk purists may want to look back past the North Mississippi Allstars to their respective decades. In fact, those wanting a real taste of hill country roots will either have to go to Mississippi or buy a Smithsonian reissue. But anyone looking for a contemporary take on blues, its origins and its dubious offspring should give North Mississippi Allstars a try.