If you think an evening of Finnish folk music sounds a little low energy, or a bit too rarefied, you haven't heard Värttinä. This group of wildly original singers and instrumentalists will be in concert Thursday in Duke University's Reynolds Theater.

Värttinä pretty much invented the style of music the ensemble plays, said band member Jaane Lappalainen. At times their music is reminiscent of Cape Breton fiddle music, at other times traditional English ballads. Their more boisterous tunes bring to mind the band Afro Celts' hybrid vibe.

"People all over the world hear different things in our music, and describe it differently, which is a really good thing," said Lappalainen. "That tells us that we've got something original."

While everyone may come away from a Värttinä concert with a different take on the music, the consensus among European audiences has been overwhelmingly positive. Värttinä's sound is arresting and entertaining.

Värttinä was started in 1983 by Mari and Sari Kaasinen's mother, who was keenly interested in Karelian culture. Karelia is the part of Finland where the original members of Värttinä lived.

"Mari and Sari's mother had them singing some melodies and reading traditional poems," Lappalainen said. "People began to ask if the girls could come to sing at parties and such, which they did, and that led to them getting more exposure. Soon other girls wanted to join with them, so the group grew larger.

"Then they came to me, because they were thinking that they could use some other instruments besides just the kantele [a stringed instrument and the national musical instrument of Finland]. Little by little we added other musicians to the band. At its largest, I'd say Värttinä included 21 members."

The year 1989 was a crucial one for the group. Many of the members were of an age where it was time to decide between pursuing careers or remaining with Värttinä. Lappalainen was one of the members who chose to stay.

"Those of us who wanted to continue with the band worked to become more skillful at the music," he said. "We also added some professional musicians to the group at that point. This was the start of new Värttinä. Before 1990 it was a hobby; after 1990 it was our profession."

While the ensemble writes original music, its compositions are deeply rooted in Finnish tradition, Lappalainen said. "One idea is the use of old poems, which people used to improvise, to tell different stories. But there's a certain meter for lyrics people used to use to relate these poems, which is really ancient -- like a thousand years old -- and we're still using the same kind of language and the same kind of meter for the lyrics of our songs. The basis for our music, for our melodies, is also old traditional tunes ... We're writing original music, you see, but our roots are in this ancient music and poetry."

But the combination of music with poetry in a unified form is what gives this ensemble's sound its originality, Lappalainen said. "Of course, in those old days, the music and the singing [poetry] were two separate things that weren't done together, so we've had to create a new style of music," he said. "We had to find a way to combine these two traditions into one thing, one music, so to speak. That's why, for most Finnish people, our music sounds so original. There hasn't been a style like ours before we invented it."

The national archive in Helsinki has provided a treasure trove of tapes and old books that Värttinä has mined for ancient poems.

"Värttinä is about doing original music, however," Lappalainen said. "We remember where we're coming from, but we have to put ourselves in it, or else we're not being true to ourselves. It gives more meaning to the music if you're telling your own stories, or expressing your own feelings.

"If you try to create something new, there will always be people who oppose that," he added. "Even when we were young we were trying to do our own thing with the music. Sometimes at music festivals conservative people would say to us, 'You can't do it like that! That's not right.' We would say, 'We don't care. We're having fun.' "