The Avett Brothers will play Sunday at the Newport Folk Festival.

Since forming in 2001, The Avett Brothers have become one of the rising phenomena of roots music, with original acoustic music that honors traditional music while taking in the mix of influences that typifies the best rock ’n’ roll. Along with their studio work, which includes last year’s Emotionalism and the sprawling semi-concept album Mignonette, the relentless touring of Scott and Seth Avett and bassist Bob Crawford has also resulted in two live albums that capture the band at their most raucous.

But the big recent news for The Avett Brothers is their signing to American Recordings and their work with legendary producer Rick Rubin. They met with Rubin for about a year “talking about music and ideas,” Crawford says, gave him demos of 32 songs around Christmastime and tracked 16 of them for a new record in a one-week session about a month ago. They’ll go back to the studio for overdubs and mixing soon.

Crawford says that working with Rubin has been “a great learning experience and a great growing experience. . . . In a way, it’s a whole new world for us. But his personality, the engineers’ personalities — it’s like a whole new world that fits perfectly in the world that we’ve already created for ourselves.”

The major difference in working with Rubin, Crawford says, is the flexibility to work out song ideas in the studio, rather than going in with arrangements, tempos and structures that have been pounded into shape on the road for a year. “Which, up until Emotionalism, was how it was, not because it had to be that way, but because that was how we knew it. Then with Emotionalism, we started playing around a little. And this is the next step of that. . . .

“A lot of the demo aspects fell to the floor when we started working on them. It really pushes you, but it’s a great way to do it. . . .Sometimes [Rubin will] say, ‘I think something needs to be different here, but I don’t know what it is. What do you think?’ It’s like being in school; it’s the most exciting internship you could ever have in your life.”

Crawford says the move up to a bigger label and working with Rubin are steps that the band has been preparing for for a long time.

“There’s been a maturing process” since 2001. “There’s a continuous songwriting process. And if you do anything enough, it’s going to tighten up. . . .

“We’ve had three years in a row of being on the road 200 nights a year, so all the experiences stack on top of one another. And I think in the past year there’s been an acceleration of maturing, of knowing each other as people.”

They bring that knowledge and that tightness into the studio with them, and Rubin adds his own experiences.

“He brings the experience of hooks — record-making 101. . . . No matter how long our relationship lasts, we’re going to come away with something. You’re going to gain the benefit of experience.”

Crawford says that he joined the band as part of a career change. He was working in film and video production and came down to North Carolina from New Jersey in 1996, feeling that he was at a crossroads. “I saw a lot of guys I had been working with, and they were a bit older than me, and they were kind of crabby, and they had all the material benefits of life, but they were wanting more, because that job takes it out of you.”

He decided he wanted to learn about music “from the ground up” and went to school to study jazz guitar. At the same time, he bought an upright bass and “started messing around. Before I knew it, I was getting gigs, playing with people before I really knew how to play,” in several groups. He met the Avetts, auditioned for them in a parking lot at 10 p.m. on a Sunday, and says his first impression of them was “they’re little Eddie Vedder copies, in their cutoffs and their flannel shirts.”

But the music hooked him. While it was acoustic and traditionally based, it was original, with a variety of influences. “It didn’t fit with the traditional music, and I was very intrigued by it.”

And while the Avetts’ music avoids the aping quality of revivalism, the independent spirit and the loose nature of the creative process feels traditional. “We’ve really gotten away from that aspect of music,” Crawford says, “but I think we haven’t gotten that far.”

They’re still road warriors. Crawford was speaking from home last week, but the schedule is still full. “There’s never been a tour. It’s been an endless tour. It’s always been a matter of a couple days gone, a couple days home.” More realistically, he laughs and characterizes it as “Three weeks gone, two days home; two months gone, five days home.” Since the end of February, they’ve been “pretty much gone.”

And while he’s never been to a Newport festival before, he’s raring to go for this one.

“I am so excited, because I am a lifelong festival-goer myself. I’ve always dreamed of going to the folk fest or the jazz fest, and I can’t think of a better circumstance to attend my first.”

The Avett Brothers play on the Harbor Stage on Sunday.

rmassimo@projo.com