If you go

What: Greensky Bluegrass

When: Doors at 8:30 p.m. Friday and Saturday

Where: Fox Theatre, 1135 13th Street

Cost: $15 advance tickets, $18 day of show

More info: greenskybluegrass.com, foxtheatre.com

J ust a few minutes into a phone call from Carbondale, Colo., there's a buzzing from Anders Beck's phone.

"Sorry if there's buzzing," the Greensky Bluegrass dobro player said. "My phone's starting to go off with the 'woo, see you in Telluride' kind of texts."

The Michigan-based progressive bluegrass band is headed back to the Telluride Bluegrass Festival, at which they won Best Band in 2006. They'll play in Colorado a lot as the weather warms up, including a night at Red Rocks Amphitheatre.

It's easy to forget they're not a Colorado band.

"[In Carbondale] there's a wood burning stove, dogs off leashes -- it's that mountain vibe we like," Beck said. "People often think of us as a Colorado band, which is a compliment."

Over the years, Beck, Michael Arlen Bont (banjo), Dave Bruzza (guitar), Mike Devol (upright bass) and Paul Hoffman (mandolin) have had a growing fan base thanks to a style progression that moved from traditional bluegrass to something more progressive and rock-leaning.

"It's been an interesting trip for us, as well," Beck said. "The reason that we picked up mandolins and banjos and dobros and acoustic upright basses was because that music was really interesting to us. That was sort of the jumping off point. We played a bunch of bluegrass and sort of realized, 'OK, that's that.' And we love it, but how do we meld all of our other influences into music to something that's us?"

It's been about two years since Greensky Bluegrass' last studio album, Handguns. That record was already inching away from bluegrass tradition (but not too much) and Beck said the record they just finished recording will creep away from that a little more.

"Handguns was where the bar was set," Beck said. "Our goal for that record was to make something bluegrassy, but a little darker than your usual bluegrass album. I think it really accomplished that while still having the bright and happy sounds of the banjo and mandolin. It's the bluegrass contradiction, these happy sounding songs about murder and stuff."

"The new record, I don't know if there was an overall goal, but it's a little more kind of indie sound. Not totally indie rock, but more sort of another step away from bluegrass."

Fans need not worry that Greensky is trying to ditch its roots. The different sound is a result of new and changing influences, rather than a grab for huge commercial success.

"A bunch of the songs, there's still some significantly bluegrassy stuff, but overall I think the sound is kind of another step away from traditional bluegrass," he said. "Just like Handguns was one step away, for no other reason than we're just trying to create something that's unique and ours. It's not like we're trying to create a Mumford and Sons hit. Paul, who writes the majority of the songs, what he listens to is a little farther removed from traditional bluegrass. He's listening to Deathcab for Cutie more than Bill Monroe, and most of us are, too. I think that really comes off in the music we make."

While Greensky is in town, maybe they'll try out some of the new material. Or maybe they'll go old-school. From the sound of it, anything could happen.

"We love playing Boulder and Fort Collins," Beck said. "The crowd in Boulder is so awesome and really attentive and interested in our musical exploration. We improvise a lot on stage and Boulder always seems to be one of those places-- and Colorado in general -- where they appreciate that side of quote unquote bluegrass music."

Call it whatever you want. Go listen anyway.