A couple of weeks ago, the masochists at NPR posted a video clip of an attempted conversation with members of Sigur Rós, titled "When Good Interviews Go Bad." The pauses between question and answer are painfully long, the answers brief at best and completely disinterested at worst. You'd almost think the whole thing was a joke if it were the least bit funny.

Surely the Icelandic band isn't a bunch of sour pusses. Neither do they seem particularly antagonistic. But at this point one imagines the only thing tougher than speaking to Sigur Rós about well-trod subjects-- invented languages, Iceland's music scene-- is actually being in Sigur Rós and constantly getting asked questions about music all but designed to speak for itself. The group's sound is so meticulously composed, recorded, and performed it's no wonder it often evinces the same sorts of reactions to its otherworldly beauty, grace, and quiet catharsis.

Speaking of the music, it's been a while since anyone's gotten any from Sigur Rós. The group's Takk… was released in 2005, and following a tour things were relatively quiet, at least until a handful of surprise performances earlier this year. It turns out the group was indulging in the tried-and-true rock band placeholder tradition, filming itself for a concert film-cum-documentary, Heima that captures the group in its element at home. Sigur Rós have also bought itself some more time with Hvarf-Heim, a companion compilation of mostly unreleased songs and a brief acoustic set.

Sigur Rós seem the least likely candidate to go unplugged, which is one of many reasons why Heim is so remarkable. It's Sigur Rós recast as chamber music, the gorgeously sculpted dissonance of the band's material recast for strings, harmonium and far more tactile instrumentation than the usual bowed electric guitar or thundering percussion. "Samskeyti" and "Ageatis Byrjun" now sound curiously suitable for Windham Hill, and Jonsi's vocals are warmer on "Staralfur" than they are on the fully fleshed album version. Even when he hits the high notes at the end of "Vaka" it comes across a restrained counterpart to the kind of volcanic dynamism the group is typically known for. The originally hushed "Heysatan" comes off somehow more intimate, emphasizing the power of melody over meaning from a band that already often seems to prefer the amorphous cloak of mystery.

The familiar Sigur Rós we all know (and many love) is what's on display over the course of Hvarf, newly recorded versions of three never before released songs and two from the group's pre-breakthrough early days. "Salka" dates back to 2002 and supposedly almost made it onto the () album, its beguiling introductory melody hinting at "O Come All Ye Faithful" before leading to a typically grandiose string-laden coda. "Hljomalind", which the band at one point tagged the generic stand-in title "The Rock Song", is indeed more standard issue than what the band usually drums off, sounding a bit like a leftover from the Cure's Disintegration if Robert Smith sang in a falsetto and draped everything in reverb. The band essentially concedes the song's mediocrity on their site, which makes one wonder why they couldn't dust off something better.

"I Gaer", on the other hand, marks an interesting change of pace for Sigur Rós, comprising a taste of what they jokingly call their "brief prog-rock excursion." It's the closest that Sigur Rós have come to the epic Pink Floyd aesthetic some have ascribed to the group, beginning with gently chiming bells before exploding into a full-on organ, guitar and plodding drum maelstrom. It's a bit silly in its pomposity, but no less fun for it, especially from a band usually about as far from fun as an ice storm.

The last two songs on Hvarf stretch back to the group's Von era, including the title track, which has grown and changed over the course of the past 10 years. The new version is almost twice as long and far more fleshed out than the somewhat anemic album version, which the band in part attributes to the contributions of the sympathetic chamber outfit amiina and drummer Orri (who came on board after the recording of 1999's Agaetis Byrjun). The new arrangement really brings out a beauty that was only previously hinted at.

The new version of "Hafsol", on the other hand, not only makes the album version seem like a sketch at best, it actually turns out to be one of Sigur Rós' few honest to goodness anthems, ending in a collision of droning noise and a sprightly string figure before placidly fading like a sinking sunset. It's ten minutes of bliss that should keep the faithful satisfied until the group reconvenes and produces something new, resuming the road to parts unknown instead of dusting off the path that leads back to where they came from.