The audience of mostly early twentysomethings clustered in Boston’s Roxy on this crisp fall night looks like a typical jam-band crowd. Baggy jeans and loose T-shirts are the uniform, a few backpacks display pro-hemp stickers, and several groups of young men are kicking hacky sacks as they wait for the band to take the stage. In the taping section, a fenced-off zone next to the soundboard in the middle of the spacious, high-ceilinged room, some fuzzy-haired recordists are earnestly setting up their portable decks.

But when the music starts, it seems there’s been some mistake. A slide guitar akin more to the focused intensity of Duane Allman than to the congenial ambling of Jerry Garcia rips through the speakers. And as the band’s performance continues, the four men on stage seem determined to travel back through time. A song called "Freedom Highway" rings like an echo from the ’60s civil-rights movement, with its pointed message and chanted chorus. Another number begins, and the two guitarists’ interlocking tones build a rickety kind of architecture — albeit supported by a steel beam of bass and drums — that peels back another decade. It’s a shambling sound that was perfected by electric musicians in Mississippi, a one-chord drone supporting weaving patterns that are both melody and rhythm. It seems more African than anything in the rock lexicon, at least until one of the guitars breaks into an extended flight of warmly shrieking slide that wanders willfully toward weirdness.

The tune is "All Night Long," by the late Junior Kimbrough, who perfected the singular style of playing it’s based on in Holly Springs, Mississippi, roughly 45 years ago. It’s unlikely that even five percent of the hundreds in attendance have any idea who Kimbrough was, but that doesn’t stop them from dancing to the North Mississippi Allstars’ translation of his music. Or for that matter to "Old Black Mattie," a number that seems as old as the Mississippi hills, where it was written, or to "Shake ’Em On Down," which is attributed to the Memphis bluesman Bukka White, who died in 1977 after a long life of rambling.

The way the Allstars’ repertoire of aged covers and new originals based on time-honored blues themes — all delivered with the wicked thrust of rock and roll — is being embraced by the jam-band crowd is proof that even this conservative audience is looking for something new. And the band’s second Grammy nomination, announced this month, is proof that Boston isn’t the only place that’s giving the group this kind of reception.

The North Mississippi Allstars, who live roughly an hour south of Memphis, have found an avenue to indie-label rock and its audience that draws on their region’s musical and cultural roots. Their solidly grounded approach is refreshing at a time when much of what’s being played on radio and in the clubs — the post-apocalyptic sound of new metal, the strummy tones of frat rock, the electronic mixes sprung from sampling and DJ culture — seems redundant and heartless.

The Allstars are not alone. There’s a new generation of rockers born below the Mason-Dixon Line who have sidestepped the clichés of the regionally grounded music that came in the immediate wake of the Allman Brothers and Lynyrd Skynyrd to create a new kind of Southern rock. And their sound, which taps the blues, R&B, and pop music of the ’60s and earlier decades, seems to be infiltrating the indie underground much as the funky, history-respecting work of so-called Dirty South rappers from Memphis, Atlanta, and New Orleans crept into the world of hip-hop.

The Allstars, Lucero, and Will Kimbrough — who’ve all recently released CDs — are among the best of the new Southern rockers. The Allstars in particular seem to have been bred for this. When the band’s founding brothers, guitarist Luther Dickinson and drummer Cody Dickinson, were in their early teens, their father, the legendary producer and pianist Jim Dickinson, returned the family to the Memphis area "as part of my sons’ ongoing roots-music education," he explains by phone from their home in Coldwater, Mississippi.

They learned well. Although Luther and Cody had formed a hardcore punk outfit in their early teens named D.D.T that enjoyed some notoriety, before they graduated from high school they discovered that the hill-country musicians Junior Kimbrough and R.L. Burnside were practically their neighbors. Inspired, they started the Allstars as a duo — a typical band line-up in rural juke joints — and drew from the bluesmen’s repertoires. Luther also apprenticed himself to Othar Turner, the nonagenarian farmer and hand-cut-reed fife blower who dominates the region’s indigenous African-American fife-and-drum music. When it came time to expand the Allstars, they drafted bassist Chris Chew from the area’s thriving gospel scene and, later, pulled in Dwayne Burnside, R.L.’s son. Together they make up one of live rock’s most formidable contemporary bands, reaching the level of blues-rooted but blaring ensemble playing that distinguished the Allmans in the early 1970s.

When they played the Roxy in November, they were touring behind their second disc for the Wellesley-based Tone-Cool label, 51 Phantom, which was nominated for a Contemporary Blues Album Grammy this month. "Coming from Memphis and North Mississippi, there’s just this tremendous amount of great music to draw on in terms of blues and rock and roll," Cody explained backstage after that performance. "But the audiences at home can be really tough. They know how this music should be played."

His father was also a hard judge. Jim Dickinson’s musical roots are in the ’60s Memphis blues scene. He’s produced albums for Ry Cooder, Big Star, the Replacements, and the Allstars and has played piano on sessions for everyone from Petula Clark to Aretha Franklin, the Stones, and Dylan. Luther explains, "So much was available to me, but I just didn’t know until one day I woke up to it. My dad had to search and dig for his amazing record collection. I grew up with it, plus everything else that was coming out on CD. So I had all the blues from the ’20s through the ’50s, plus Hendrix, Cream, the Allman Brothers — all of the classic rock. Plus, though I didn’t appreciate it at the time, the greatest blues was being made just a couple miles down the road. Once I found my way to Junior Kimbrough’s place and R.L.’s and Othar Turner’s, I didn’t have to research anymore because I was right in the middle of it."

When the Allstars headlined the Paradise early last year, they brought along the Memphis band Lucero to open. Although Lucero don’t play a single blues lick on stage or on their first album, Tennessee (Mad Jack), both bands sound unmistakably from the area where the Mississippi River rubs up against the high bluffs of the Southland. But Lucero’s roots are more urban. "Chain Link Fence," with its gentle wah-wah guitar and string arrangement, recalls Isaac Hayes’s hot-buttered soul. "Fistful of Tears," with its moon-eyed crooning, could be one of Memphis rocker Alex Chilton’s ballads, and the chiming guitars, pop hooks, and harmonies of their most energetic songs could have been recorded by Chilton’s one-time band Big Star. It’s notable that Big Star were produced by the Dickinson brothers’ dad, and that Cody produced Tennessee.

There’s one more influence in Lucero’s melting pot, and that’s the Memphis area’s country-music legacy. In particular, the ballad "Nights like These" zeroes in on the spirit of the first recorded urban cowboy, the sophisticated pianist and soulful singer Charlie Rich, who cut singles for Sam Phillips at Sun Records long before he became a major star in the 1970s.

An affection for Rich’s emotional songwriting is something Lucero share with Will Kimbrough, a Mobile native who now lives in Nashville and is absolutely not related to Junior Kimbrough. For his second solo CD, Home Away (Waxy Silver), Will Kimbrough penned a song called "The Crackup" that straddles country, soul, and ’60s rock. Both the story, which focuses on a friend’s divorce troubles, and Kimbrough’s vocal performance tap Todd Rundgren’s "We Gotta Get You a Woman," but with a soulful Southern twang. Kimbrough describes the tune as a tribute to the AM pop radio he grew up on, "where Todd Rundgren, the O’Jays, Chicago, and Charlie Rich all co-existed."

Although the rock-and-roll heart of Kimbrough’s music beats may lie in growling guitars and arrangement ideas that ricochet from John Lennon to Harold Melvin, its brain is wired on country-style narrative, which is often sparked by marriage, divorce, or loneliness. Then there’s "A Piece of Work," the opening track, which comes off as a hard, smart-ass blues shuffle with its slide guitar and rumbling locomotive rhythm. Kimbrough describes it as an effort "to channel Johnny Cash and Othar Turner via an imaginary Internet chat room."

Of course, the Southern tradition of mining rock from a distinctly regional vein didn’t dry up after Molly Hatchet, 38 Special, Charlie Daniels, and the other B-level artists that followed the Allmans. "I always thought R.E.M. was Southern rock, although they never called themselves that," Jim Dickinson remarks. He’s been a keen observer of the style’s permutations from its very beginnings.

The night before we spoke, Dickinson had played the Oxford (Mississippi) club Proud Larry’s with Jimbo Mathus, another Memphis-area musician who might become as potent a proselytizer for the new Southern sound as the North Mississippi Allstars are if his Knockdown Society get a break. Like Cody and Luther Dickinson, Mathus took a while to discover his musical heart in a raw, distorted sound that could be coming from the open door of a juke-joint twilight zone. His previous group, the Squirrel Nut Zippers, were a fey re-creation of early American string and parlor music mired in self-parody. But as the Zippers ran their course, Mathus discovered the blues of the Mississippi hill country. He re-emerged as a blistering guitarist on Buddy Guy’s 2001 album Sweet Tea.

"It’s great to see young musicians picking up the mantle," says Dickinson, whose recent Free Beer Tomorrow (Artemis), his second solo recording in 30 years, proves he’s also still carrying the torch. "We take our music serious in this neck of the woods, and when you see bands like this come back up again, you know something’s really happening. All the way back to the start of the Country Blues Festival in Memphis in 1965, there’s been a kind of connection between the Memphis and Arkansas blues artists and the bohemian underground around Memphis. Bands like the Insect Trust and the Electric Blue Watermelon and Tav Falco are the obvious links, but that leads up to Jon Spencer and the new blues-inspired street-punk sound.

"Basically, it’s all Southern rock. Southern rock is what happens when crazy white boys try to play the blues, because they can’t do it. But what comes out . . . well, you gotta call it something."