For a band of musicians, stepping onto a tour bus for the first time after years of flogging asphalt in somebody's decrepit van is a rite of passage. "We're just trying to get acclimated," says Avett Brothers bassist Bob Crawford via cell phone as he boards the bus at a stop in the Midwest. "The bus is potentially a great thing—it's a new step for us, a new experience."

Crawford speaks often of new steps as he gives the abridged version of the band's history. Since the group's official formation in 2001, change has come at such a pace that Crawford himself finds it difficult to quantify, let alone explain. "We started gigging around home in North Carolina, and right away we saw that crowds really seemed to like our music. I can't describe why, exactly, but they did, so we kept at it."

Describing the "why" of the Avett Brothers' success—and even the "what" of the band's music—has proven an irresistible challenge to the press, which has directed the band into a number of genres and in some cases invented new ones. The Washington Post called the band's sound "post civil-war modern rock;" a few others lump it in with "grungegrass." Yet these phrases fail to recognize the unmistakable smoothness of the Avett Brothers' pop-sensible melodies.

"I don't know how reliable genres are, other than knowing where to find something in a record store," Crawford says. "I grew up listening to a lot of classic rock: Pink Floyd, Jethro Tull, Led Zeppelin. They're all so distinctly different, yet they're all roped together under the name 'classic rock.'"

The band's evolution at least partly accounts for the confusion. Soon after Seth and Scott Avett's rock band Nemo bit the dust, the two hooked up with a crew of local musicians, jamming on mostly old-timey stuff. Bluegrass, country and folk tunes were the norm. As Crawford describes it, the old style was "a starting-off point, like it is for a lot of bands. We don't really embody it anymore, but it was a good place to jump from. We've developed our own thing now, but playing [blue grass and folk] left us that with a nice earthy and organic feel."

The band's latest album, Emotionalism, contains a hodgepodge of folk and pop melodies, mixed vigorously with a stripped-down approach derived from acoustic instrumentation and the unmistakable twang of the banjo. Nevertheless, a pop sensibility undergirds the album, giving way to melodies that are more Beatles than bluegrass. "We sound how we sound," offers Crawford. "I can't put a finger on it. We all love old-time music, yet we all love punk, Weezer and Neil Young." 

Santa Cruz is no stranger to the rustic eclecticism the Avett Brothers promise to deliver at their upcoming performance at the Rio Theatre. The success of local trio The Devil Makes Three has fostered a fascination with a kind of hillbilly roughness crossbred with  pop-inclined refinement. Though the Avett Brothers sound nothing like The Devil Makes Three (really, they don't), the comparison is inevitable because of the underlying philosophies of both groups. Taking bits and pieces from more than a century of American music, the Avett Brothers and The Devil Makes Three represent the latest resurgence of roots music, and audiences are eating it up.

"Pop music wasn't always just Britney Spears and that stuff," remarks Crawford. "Pop used to be great—look at the Beatles. Hopefully, it'll go back to that."

Exactly what popular music will sound like in the future is anybody's guess, but bands like the Avett Brothers seem poised to become its foundation. Like the Beatles, the Avett Brothers explore rock & roll's endless avenues, taking in a wide spectrum of music and then stamping it with a wholly original style. "A lot of great bands, and artists in general, have one overall sound that they always go back to," says Crawford, before noting the distinction. "We like to mix it up—try different harmonies, add a cello to change the texture. Our sound reflects the feeling of whatever space we're in."

THE AVETT BROTHERS play Thursday, April 3, at 8pm at the Rio Theatre, 1205 Soquel Ave., Santa Cruz. Tickets are $20, available at Streetlight Records or online at ticketleap.com.

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