Kentucky quintet My Morning Jacket may well be on their way to becoming big, but I'm not sure because I don't know if I know what's big anymoresometimes I feel more out of it than Abe Simpson. I do know I've been hearing more and more about them from my listening post here in this corner of the music world, and they certainly have the requisite trappings for building a buzz: near-apocryphal studio stories (something about recording in grain silos, check), endearing quirks (playing barefoot, check), appropriately enigmatic imagery (the vaguely ominous title of their latest album, It Still Moves, and its cover shot of a tinsel-draped stuffed grizzly bear in what appears to be an octagonal attic). Even their shorthand tag, MMJ, rolls off the tongue as conveniently as any WSP, SCI, or DMB.

And the buzz is clearly spreading. The last time they played the city, it was in a matchbox-sized nightclub, but with tonight's appearance MMJ has graduated to Atlanta theaters, and in the meantime they've notched a well-received appearance at Bonnaroo. I've owned It Still Moves since the winter, having picked it up based on strong word of mouth and its place on several year-end best of lists, but missed their previous Atlanta show and Bonnaroo to boot. It Still Moves is certainly a solid record, but the question with bands always comes back to whether or not they can cut it live, so I walked into the Roxy last week with the critical issue of MMJ's live chops still undecided, and in some doubt due to a recent lineup change (the departure of guitarist Johnny Quaid and keyboardist Danny Cash). When I walked back out a few hours later I was more than a little surprised—if the Beach Boys-meets-Grant Lee Buffalo vibe of their last disc is what you know of My Morning Jacket, the punch of the band's live show may catch you a little off guard as well.

The set started off essentially as expected, with low-key takes on low-key It Still Moves tracks "Golden" and "Just One Thing," the opener complete with a soft rain shower of pedal steel. But things soon took a detour away from the ethereal and splashed down into muddy Black Crowesian stompthe surging "One Big Holiday" and "Dancefloors," also from their latest, showed MMJ isn’t exclusively about dreamy cathedrals of emo-jam. Frontman Jim James is something of a walking contradiction, arriving onstage sans footwear but accessorized with what appeared to some kind of dinner jacket (which was doffed after the third number when it became too hot), his stout build and face-obscuring mane belying a voice that’s all Neil Young meets Jeff Buckley, and in person the vocal effects sent a strong vibration through my beer can. Once comfortable in the Roxy, James flexed a surprising amount of guitar-hero muscle and a stage presence that was a all power-rock head whips, whirling dervish aerobics, and a strange grab bag of one legged pogo-stick bouncing and Elvis karate moves, frequently joining bassist Two-Tone Tommy and guitarist Carl Broemel in front of Patrick Hallahan’s drum riser for an old-time power chord session. Not only does he get a workout, but his guitar tech gets one tooJames switched weapons on nearly every tune as the show ran through much of It Still Moves and selected cuts from their previous album, At Dawn, culminating in the scruffy romance of "Mahgeetah." At the conclusion of their set, the band slipped offstage quietly to a magically inflated life-sized ghost balloon, complete with the word BOO in big letters on its chest, joining an already present plastic Jack O'Lantern to lend the show a completely unexplained and inexplicable Halloween-in-June flavor, more proof that this is a band intent on sending their own mysterious messages, mass acceptance be damned.

But this mass on the Roxy floor wanted more, and was thus delivered an encore of "At Dawn," "Steam Engine," and a longish jam into "Run Thru." Then My Morning Jacket was gone again, off to other points, having amply demonstrated that their agenda leans as heavily toward the epic excursions of 70's AOR as it does mellowed-out forays into romantic longing. A band like this coming from Kentucky seems as improbable as cruising the Appalachian foothills with the car radio on AM and somehow, amidst all those stations bellowing religion and weird bursts of static, finding one channel that plays nothing but Radiohead's The Bends. While the jury is still out on My Morning Jacket's staying power, I saw enough this night to know that whatever they do next definitely bears watching.