PHOTO COURTESY OF BIG HASSLE MEDIA Yonder Mountain String Band play high-energy, improvisational bluegrass music that gets their audience to dance, even without a drumbeat.

Yonder Mountain String Band makes bluegrass music the same way companies make their bottled water: pure, fresh and straight from the snow-covered hills of Colorado.

Not bad for four guys from the suburbs. In fact, the members of Yonder Mountain String Band are probably the last people you'd ever expect to be making bluegrass music. Adam Aijala, who plays acoustic guitar, went to the University of Massachusetts and grew up listening to the Dead Kennedys. Mandolin player Jeff Austin studied dance and musical theater at the University of Cincinnati. Dave Johnston, who plays banjo, went to the University of Illinois. Ben Kaufmann, Yonder's upright bass player, moved to Colorado, where he met the rest of the band ÷ after studying film at New York University.

But don't worry about the group's authenticity: Yonder may have strayed far from its suburban roots, but they've all been into acoustic, folk and bluegrass music for a long time.

Aijala spoke about his own unlikely career as a bluegrass musician while the band was unloading equipment for the first date of their tour in Flagstaff.

"I definitely had to say I got into bluegrass via folk music. I was into punk and metal. But I got into the Grateful Dead, and there was some banjo in their stuff," he said.

Check This· Yonder Mountain String Band headlines the Rialto Theatre, 318 E. Congress St., tonight at 9. The Hacienda Allstars open the show. Tickets are $12 in advance, $15 at the door. Call 798-3333 for more information.

Aijala, who had been playing electric guitar since he was 13, first tried another instrument before settling on the acoustic guitar.

I had been trying to learn banjo, but then I was like, "Screw this. It's too hard," he said.

He cemented his career as a bluegrass musician (he was a forester before leaving the East Coast) when he moved to Nederland, Colo., where he met the other members of Yonder Mountain String Band.

"All four of us grew up listening to everything but bluegrass," Aijala said. That included lots of Frank Zappa, Jimi Hendrix and what Aijala described as "classic rock stuff."

The band formed only two years ago, but its massive songwriting output (two studio and two live albums) and touring schedule has helped hone the group's skills; Yonder played 170 shows in 2002 alone. Also on its list of touring accomplishments are four sold-out shows at the historic Fillmore Auditorium in San Francisco, as well as sold-out shows in Portland, Ore., New York City and Austin, Texas.

The band members' goal throughout all their shows has been to refine their playing (the band needs to practice only new material or, as Aijala says, "when something goes bad"), as well as get their audience to dance. And they do all this without the aid of a drummer. Their band has been so successful without one, in fact, that the band has never considered changing their lineup.

"I don't think we would, ever. We've had drummers occasionally. There are a lot of bands with that setup already. Sometimes when someone's backstage and they've had a little too much to drink, I mess with them. They'll ask me what I play and I'll say, ĪDrums.'" Yonder's sound is so full that people often assume that there's a drummer behind those strings.

The band is successful enough that its members are not in danger of having to switch careers. But Aijala, who had to quit forestry because of a knee injury, thinks about what he'd be doing if he hadn't taken up bluegrass music.

"It's something I like to think about. I'd maybe go back to school, maybe take something forestry related ÷ like agriculture," he said. But, he adds, he thinks he's very lucky to be playing music for a living, even though he would have never guessed he'd be a bluegrass musician.

"We all picked up bluegrass later in life. We're trying to play bluegrass, but it's not in our blood. Actually, it might be starting to get in our blood now. "