A cluster of vocals moves in unison, like a group of white clouds drifting lazily across a blue sky. The unaccompanied harmony is soon joined by a clucking, ticking mandolin, and by the time the second track is underway, the music has fully evolved into momentous, widescreen rock. Neatly folded acoustic guitars sit side by side with circular, loping electrics, while autoharps and dulcimers provide earthy backbone; curious drones and malleted, gong-like cymbals give the songs an Eastern flair.

So begins Sun Giant, Fleet Foxes' glorious first release for Sub Pop, which has already garnered flurries of praise around the blogosphere. They were one of the buzz bands at this year's South by Southwest, reaping plaudits for tight vocal arrangements and a mystic, inventive style that gives equal share to each instrument. However, this carefully balanced sound did not pop out of nowhere. The origins of the band started back in school with friends Robin Pecknold and Skye Skjelset.

"We actually have been playing together since the two of us learned guitar at age 13 or 14," says Pecknold. "At some point we thought it would be fun to play with a full band instead of just the two of us on acoustic guitars, so we rounded up some new friends we'd made after moving to Seattle. But since 14 or so, we've never stopped writing songs or playing music together, even if since that time we've probably thrown out our whole catalog of songs three or four times to get to these songs now."

The band has advanced from the clear-eyed classic rockisms of their 2006 self-titled EP, with newer material taking those customary sounds and filtering them through sun flares, soft lenses, and colored silk scarves. At times, Fleet Foxes sound like David Crosby's marijuana-bleary If I Could Only Remember My Name with better songwriting and tighter focus, and there's enough billowing reverb to fill My Morning Jacket's grain silo. Regarding the band's signature vocal style, Pecknold says, "An hour and a half every practice is devoted to just singing. It wasn't our intention to find a group of guys that were all strong singers; the focus was more to spend the time singing together to get to know each other's voices." Songs are built carefully, stacked like houses of cards, with dynamics carefully put in place and no one player dominating. It's exotic and familiar in equal doses.

While the Sun Giant EP is proving to be the world's introduction to Fleet Foxes, a full-length album is due out later this spring. Interestingly, the album was recorded prior to Sun Giant. Pecknold explains, "When we first talked to Sub Pop, they let us know the next available slot they had to put out a record was in June—this was in December when we had just finished the LP. It's good that every band gets to have a time when their record is the label's main focus, so we weren't bummed about the long wait, but we'd worked out new songs since finishing the LP that were kind of their own little batch. We came up with the idea of an EP and were back in a studio in January for a week and a half to record Sun Giant. The EP and LP are sort of a pair, and they'll be packaged together on vinyl."