The Avett Brothers are onto something. They've combined a country-folk aesthetic and a deep interest in blues and bluegrass with a punk edge. If that composition seems awkward and untenable, try listening to 2007's Emotionalism or the tour de force Four Thieves Gone: The Robbinsville Sessions. There are dizzying valleys and peaks, shouts and stomps coupled with graceful fingerpicking and thumping bass. The albums are great primers for the Carolina fourpiece that consists of bassist Bob Crawford, cellist Joe Kwon and the multi-instrumentalists Scott and Seth Avett. But the true way to experience the Avetts is live. Fortunately for music aficionados, they played the Fillmore last Friday.

The Avett Brothers take the dirty, angry sound that colors its recorded material and feed an entire live show with it. The punk and new wave ethos that originally incubated in the band's early days comes out in all its sloppy, well-meaning glory in person. Broken banjo strings and songs about killing girlfriend's boyfriends are standard fare for these Southern Sex Pistols.

Hard, fast and furious may be misleading characterizations. To be sure, Scott Avett's banjo playing is more Clash guitar strummer Mick Jones than Earl Scruggs, banjo master blaster. Yet as he slashes away at the five strings, a country feel emanates from his fingerpicks that isn't mere imitation. Dressed like the offspring of Devendra Banhart and a strict Hasid, Scott Avett can play a mean lick of banjo, pick the guitar and play drums.

Whatever instrument Scott plays, he can also harmonize with his equally talented brother Seth. The two separate may be Jekyll and Hyde, as Seth sings soft drunken driving lullabies and Scott lives in falsetto territory. But when the brothers join in harmony, they find a vocal middle that is only matched by their onstage charisma and delivery.

Bob Crawford and Joe Kwon, playing standup bass and cello respectively, have their own unique thumping chemistry. The adopted brothers engaged themselves in instrumental duels, playing eye to eye with growing intensity, on songs like "A Lover Like You" and "Talk on Indolence." Apart, they have their own fun shtick as well. Crawford strapped on the electric bass, as Kwon played the cello like a guitar.

The four onstage might be have more fun than anyone in the venue, especially when they trade lighting-fast vocals, like a quadra-barreled lyrical machine gun. The Avett Brothers kept finishing each other's words, each new voice adding a frantic pace to the singing that amounted to critical mass. Wavering on unmanageable, the band transitioned into thumping instrumental breakdown that got the rhythmically challenged audience to clap in heavy unison.

If all that wasn't enough to bring down the Fillmore, Seth and Scott's respective solos most certainly did. While Scott's song waxed angrily poetic, Seth's offered a hilarious counter point to his brother's moody yet wonderfully earnest interlude. Seth Avett talking blues were full of wickedly funny lyrics and brilliant comedic timing.

Charisma is just an added perk of the Avett's. When their banjos break or the sound goes awry, the band's calm Carolina accents placate with a gentle modesty. But when bass lines are pumping and the brothers are howling ferocious blues, you can't help but see the rock stars in formation. It helps that the Avett Brothers have found a unique sonic space that fuses country, folk and post-punk. Melding those elements in the studio is one feat, with wonders of technical production. But singing and playing that same frenzied and joyous melancholia live is what sets the Avetts apart from others.