Just because fiddle prodigy Michael Barnett has already performed at the Grand Ole Opry, Nashville’s mecca of country music, doesn’t mean he isn’t like millions of other high school seniors stressfully waiting to hear from the college of his choice. He’s waiting to hear from the Berklee Conservatory of Music, where he hopes to join bandmate and mandolinist Joe Walsh at the heralded Boston institution. Together, the duo have brought fresh energy to one of bluegrass music’s longest running acts — Northern Lights, who’ll be performing at this year’s Nashua River Folk Festival at the Pierce Homestead in Lancaster on Aug. 10.

Traditionalists have long cast a weary eye on the band, who’ve been tagged as “Newgrass” or “Progressive Bluegrass,” harking back to Northern Lights’ early days when they would throw an Allman Brothers’ song into their set list, a somewhat sacrilegious act for a music steeped in tradition. And where other groups searched for ways to “keep it real,” they made it a point of finding out what bluegrass would sound like mixed with flamenco guitars or given a peaceful, easy feeling as if it came out of California in the early 1970s.

Northern Lights debuted in 1975, releasing its first album the following year before splitting up, only to get back together again — and on a full time basis — in 1982. Soon afterwards, they were raising hell on the national bluegrass festival circuit. Three albums (or CDs, as recordings had evolved into being called) for the Flying Fish label brought them great success on the national bluegrass charts throughout the 1990s; two more CDs for Prime CD got the current century underway for the band. While the group’s lineup had evolved through the years, it received a major overhaul in 2003 when founding member Taylor Armerding left the group, handing the lead vocal duties over to Ben Demerath.

“I had to learn all the songs when I came into the band,” said Demerath. “If there’s one string that’s the remaining connection to the early ’80s when the group really had its start it would be Bill Henry, our guitar player. But John Daniel, our bassist, and Mike and Joe too, even though they’ve only been in the band about a year, they’ve got that connection because Taylor’s filled in for me at a few shows. So everyone has a connection to that past.”

And when they turn up at festivals, the old-timers still cast a weary eye in their direction.

“I think we are probably seen as more renegade in nature even than Northern Lights would have been seen even in the early ‘90s,” Demerath said. “Now, we’re even more eclectic and outside the box. That may hurt us in terms of our audience but we’re trying to expand our musical horizons.”

While bluegrass purists would most likely disagree, to my ears, there’s only a step or two between traditional bluegrass and the sound of the Allman Brothers or Little Feat.

“It’s not that far away,” Demerath said. “In this day and age, with Americana roots music, it’s a huge umbrella that covers everything from blues to rock to country and gospel to bluegrass. When you’re a progressive bluegrass band, it’s a great opportunity to push the envelope and try new things. For people outside the bluegrass audience, this is a great way to get them into this kind of music. Hopefully after they hear us, they’ll check out Del McCrory and Ralph Stanley and get the full picture that way instead of us ramming it down their throats.”

Northern Light’s latest release, “New Moon” (Fifty Fifty Music) came out in 2005.

“The last album was more of a stretch than the previous albums,” Demerath said. It surprised people with the gospel inspired “Empty Pages,” George Gershwin’s “Oh Lady, Be Good,” and the Staples Singers’ “Sit Down Servant.” Expect even more surprises when their latest recording, “One Day” (Fifty Fifty Music) is released on May 20. It’ll include an instrumental Celtic Irish jug band tune — “Monaghan’s Jig,” Bob Wills and the Texas Playboys’ Texas Swing classic “Miss Molly” and Little Feat’s “Fat Man in the Bathtub.” (You can order it through northernlightsband.com).

Demerath hopes the release of “One Day” will allow music lovers around the country to enjoy the youthful talents of Barnett and Walsh the way has as a singer/songwriter able to bask in their playing.

“That’s the exciting thing about this album coming out and why we’re excited about people hearing this band,” he said. “Both Mike and Joe are virtuosos who are incredible musicians able to play what they hear in their head at that moment.”

Of course, that’s exactly the kind of improvisation that has kept fans returning to see Northern Lights year after year.

While the 2008 Northern Lights current tour schedule doesn’t contain any shows outside of New England, Demerath’s confident the release of the new CD will change that.

“We’re played the Kerrville Folk Festival in Texas the past two years,” he said. “We hope this album will bring us back to the national market. I can see us getting out to many of the festivals around the country that I played with my band Sugarbeat in the early ‘90s. I could also see us playing Bonnaroo (a gigantic four-day festival in Tennessee that mixes the rootsiest bands with some of the most commercially successful). I don’t know why not — and Falcon Ridge Folk Festival in New York State and the Newport Folk Festival too.”

The Nashua River Valley Folk Festival will be held from 11 a.m. to 6:30 p.m., Sunday, Aug. 10 at the Pierce Homestead, 153 Packard St., Lancaster. The featured performers are Richie Havens and Lori McKenna; also scheduled are Gandalf Murphy and the Slambovian Circus of Dreams, Mustard's Retreat, Northern Lights and Susan Werner. Tickets prices are as follows: $30 early bird (through April 1) $35 from April 1 to Aug. 1, and $40 after Aug. 1 and at the gate; children ages 6 to 12, $10; children under age 6 are free. VIP admission is $125 adults and $55 children. Tickets are now available via credit card at www.lancastercoffeehouse.com or by cash or check at the Sunrise Boutique, 62 High St., Clinton, the Clinton Item, 156 Church St., Clinton or by sending a self-addressed, stamped envelope to The Lancaster Coffeehouse, PO Box 245, Lancaster, MA 01523. No alcohol, no glass, no pets, and all sales are final. If you would like to sponsor an artist or band or if you are interested in having a craft booth at the fair, please call 978-365-2043 for more information. Community Newspaper Company, the parent organization of MotherTown, is a proud media sponsor.