Pitched somewhere between the retro-purist vibe of Sharon Jones and the nervy revivalism of Jack White, Alabama Shakes possesses a curious character: they're rooted in the past but it's clear they've learned their moves musicians removed some three or four generations from the source. Instead of playing like refractions from a hall of mirrors, Alabama Shakes' 2012 debut Boys & Girls emphasizes how American roots music is now grounded in the '60s notion of blues & soul, all filtered through the prism of '70s classic rock. And it's not just that Heath Fogg tears great, gnarled riffs out of his guitar while the rhythm section of Zac Cockrell and Steve Johnson hit the downbeat with a brutal force -- lead singer Brittany Howard phrases like a rock singer, playing up vocal affections with glee, ratcheting up the drama by laying hard into her elongated phrases. Which isn't to say Alabama Shakes ignores the straight stuff: much of Boys & Girls is anchored in a Southern soul groove spliced from Stax and Muscle Shoals, the guitars of Fogg and Howard full and bold in their cleanly chopped rhythms, echoing the work of Steve Cropper and Jimmy Johnson. But Alabama Shakes aren't purists, they're modern -- they splice familiar sounds and forms together, then reshuffle them in subtly surprising ways. Unlike White or his Great Lakes cousins the Black Keys, Alabama Shakes aren't entirely enamored with what they can re-create in the studio -- they're too attached to the power of a live performance, making them an ideal candidate for a T-Bone Burnett or Joe Henry production somewhere down the road -- but they bear no special allegiance to the didactic needs of retro-rock. Their roots are just that -- roots, not anchors, allowing the group to grow, often in unexpected and quietly thrilling ways.