Chamber rock: one of the dumber genre titles in rock journalism’s staggering array of dumb genre titles. God knows what they mean by that. Pretty-sounding rock music? Hard-rockin’ chamber music? As with all rock jargon, I can’t assure that I’m “current,” but I think they’re talking about bands that put together extended rock compositions, use classical instruments on occasion, and actually appear to listen to each other when they play. Of course, all these were equally true of The Who, but I’m not compelled to label that particular group “chamber rock.”

Regardless, the term implies a certain degree of seriousness and high-art aspiration. Icelandic quartet Sigur Ros (“Victory Rose”) certainly displays these characteristics, along with a stunning virtuosity and intuitive feel for musical atmospheres. Their dark, glacial harmonies and Jon Thor Birgissen’s haunting, deeply androgynous vocals have made Sigur Ros the newest in a series of post-rock European critics’ darlings (preceded by Spiritualized, Godspeed You Black Emperor!, and Mogwai). So they are indeed “chamber rock,” for whatever that’s worth.

Svefn-G-Englar, the most recent EP from Sigur Ros, displays all the best characteristics of such a dubious classification. Sensitive group playing, swirling string arrangements, and a compositional scope roam broadly enough to encompass all the different permutations of intimacy and isolation. Fragile guitar lines and piano figures echo on the outskirts of each song while voices weave plaintively in and out of the hypnotic, icy texture. Drum patterns build from hesitant interjection to strident declaration, finally overflowing their rhythmic framework and subsiding. In other words, Sigur Ros has the formula down.

But the formula isn’t everything, and some may find themselves disappointed in the lack of variety. While Godspeed You Black Emperor! uses constant variation and flux to spin their music miles into the distance, Sigur Ros sometimes bogs down in their preset conventions. You will hear new sounds, but you might not hear them treated in new ways.

Whether or not this matters to you, the musicianship on Svefn-G-Englar remains astounding, with superb production to match. From start to finish, the music feels like someone else is listening to it (if that makes sense): the hollow, distant crackle of a radio in the house across the street. Eerie, but also sweet and comforting in a way.

For people who need a little more to grab onto, you’re probably better off with Yo La Tengo or Bedhead, where song-writing still asserts itself as paramount. But “chamber rock” isn’t for everyone — and I guess that’s the only sure thing I can say about it.