But both acts are on the bill for the upcoming Newport Folk Festival, which this year features a genre-bending mix of marquee performers that draw big crowds but don’t fit snugly under the traditional folk umbrella. The lineup is a way for the venerable festival to stay relevant amid a glut of summertime concerts while deepening the audience base for a tradition-rich event best known for the year Bob Dylan swapped his acoustic guitar for an electric one.

“If you just keep putting up the same lineup year after year that’s safe, you start narrowing and your audience gets smaller and smaller,” said Jay Sweet, an associate producer with the festival’s new production company, The Festival Network.

The festival is scheduled for Aug. 1-3 in Newport, R.I.

The Black Crowes and Anastasio, performing a solo acoustic set four years after Phish dissolved, headline the Aug. 2 lineup. Jimmy Buffett, who is rooted in folk but is best known today as the bon vivant balladeer of carefree living, plays the following day.

Stephen and Damian Marley, sons of reggae icon Bob Marley, Cat Power and alt-country band Son Volt will also be there, along with Levon Helm of the Band, Jakob Dylan and more traditional folksters like Richie Havens, who performed at Woodstock in 1969.

A newcomer to the festival, Damian Marley said he sees parallels between folk and reggae and between his father’s music and Dylan’s.

“Folk music was kind of used as a voice to express against the system or what is society’s norms,” Marley said in an interview with The Associated Press. “Reggae music has been used in that same way, to express the struggle of the people.”

Anastasio said he was grateful for the chance to play Newport, which will be his first performance in a year and a half.

“The folk music definition has changed in this fast music world and musical styles are blending really quickly,” Anastasio said in an e-mail. “It is forward-thinking and open-minded of the Newport festival to embrace different styles.”

Dick Pleasants, who hosts a morning show on WUMB-FM, a Boston station specializing in folk music, said he saw nothing wrong with diversifying the lineup or trying to draw more fans but said it would be sad if the festival were to move away from its more traditional folk roots.

“I would hesitate necessarily to call it a folk festival anymore,” Pleasants said. “But it could be the Newport Music Festival.”

Sweet, in his first year as producer at Newport, said organizers weren’t trying to break from the festival’s storied legacy but wanted to revitalize the event through a lineup of artists with broad crossover appeal and the potential to excite the crowd. That’s especially important as more music festivals sprout throughout the country.

The goal is to expose audience members to artists they’re unfamiliar with, so old-time folkies drawn to, say, Havens or Gillian Welch could join legions of Phishheads at Anastasio’s acoustic performance.

“I don’t think you last this long unless you are continually helping artists, supporting artists who take risks,” said Sweet, editor-at-large of Paste magazine, a music and film publication. “This festival has always been known as a place for artists to take chances.”

He said tickets sales were slightly better than at this time last year and that he was hoping for a sellout – 10,000 fans a day.

Since 1959, the festival has hosted a who’s who of folk performers and singer-songwriters, from Joan Baez, Pete Seeger and Peter, Paul & Mary to James Taylor, the Indigo Girls and Mary Chapin Carpenter. But it’s occasionally offered less conventional selections, such as Janis Joplin, the Pixies, and last year, Tom Morello from Rage Against the Machine.

Dylan, who debuted there in 1963, memorably pushed the boundaries two years later when he took the stage with an electric guitar in a much-ballyhooed performance that drew jeers and is credited for helping break down the barrier between rock and folk.

This year’s lineup gives a more expansive take of who and what can constitute folk music, which some fans and folk scholars say has always been loosely defined.

“The audience changes and time changes,” said Paul Dube, a Rhode Island musician who books acts for a folk coffeehouse. “We can’t just think of folk music as a songwriter sitting behind a guitar or piano singing original songs all night.”

David Hajdu, a Columbia University professor and writer who has attended about a half-dozen Newport festivals, said the question of who should properly be classified as folk is as old as the genre itself. He said the festival has always been more a tourist attraction designed for mass appeal than a pristine showcase of traditional folk.

“It’s not a scholarly academic festival. It’s not like a university-funded and organized anthropological festival of folk music in the purist sense. It never has been,” said Hajdu, author of “Positively Fourth Street: The Lives and Times of Bob Dylan, Joan Baez, Mimi Baez Farina and Richard Farina.”

Sweet said Newport fans have historically been open to new experiences, while artists who perform there understand the festival’s traditions.

“Curiosity,” he said, “is through the roof this year.”