Irish eyes will be smiling when Altan plays at 7:30 p.m. Sunday at the State Theatre.

Altan, of County Donegal, Ireland, plays traditional Irish music and is a big deal in the traditional Irish music scene, Joe Apfelbaum, programming manager of the State Theatre, 130 W. College Ave., said.

"These guys are really famous," Apfelbaum said. "They may not be household names in America, but for what they do, they're phenomenal."

Kristine Allen, program director of the radio station WPSU-FM, agreed.

"If I were to list the great Irish bands that are touring now, Altan would definitely come to the top," Allen said.

Daithi Sproule, one of the two guitarists of Altan, is humble about the group's success. He attributed Altan's popularity and longevity to a few factors.

"It's hard to explain why one group would be liked more than another," Sproule said. "The ability to keep a group together is a plus. At the time we started, no one was playing the music we were playing. We worked hard at our music. In the studio, everyone is perfection-istic."

Altan has been together since 1987, Sproule said. The group's founders, Mairead Ni Mhoanaigh and Frankie Kennedy, played together and recorded an album in the mid-1980s.

Altan's music is unique from other styles of traditional Irish music, Sproule said. Since Altan is from Donegal, the group plays in the style that is common to that area.

Most other traditional Irish music is played in the Sligo style, which is a more ornate kind of fiddling.