‘Átta’ by Sigur Rós Review: High in the Post-Rock Atmosphere

Iceland’s Sigur Rós has a sound so singular you could almost say the group created its own genre. In the context of the turn of the millennium, Sigur Rós was usually called post-rock, meaning it used the instrumentation of rock music to make something more abstract and experimental. While the tag was accurate to an extent, Sigur Rós never sounded much like any other acts labeled as such. It had elements in common with other forward-thinking outfits generally considered “rock”—the scrambled language and ethereality of the Cocteau Twins, the orchestral inclinations of Godspeed You! Black Emperor, Radiohead’s ear for electronics—but Sigur Rós had an alien quality that set it apart. And despite the group’s essential strangeness, it developed a sizable audience, perhaps because it had something musically that no one else could deliver.

The band’s debut album, 1997’s “Von,” was a tentative first step that hinted at what the group might achieve once its members had the skill to execute their vision. By 1999’s “Ágætis byrjun,” everything we would hear from this outfit for the next 24 years was already in place: the droning guitars, often played with a bow; the sound effects; the pillowy ambient interludes; and above all the soaring falsetto of lead singer Jónsi Birgisson, an element so angelic it didn’t seem of this world. Throughout the 2000s and early 2010s, the group recorded albums that expanded upon and occasionally reinvented its aesthetic, while also dabbling in soundtrack work for dance, film, and art installations. The band’s eighth studio album, “Átta” (Von Dur/BMG), out now, is its first collection of new songs in 10 years, and it pushes the Icelandic outfit’s orchestral ambitions into new territory.

There are 10 tracks on “Átta,” but the album, which runs a few minutes under an hour, is designed to be taken whole, and its structure enforces long-form listening. The music on the record is so dynamic—gliding between extended passages that are barely audible to mighty crescendos that will have the casual listener lurching for his or her volume knob—that it requires total commitment. Despite lengthy ambient sections, this is not a record for the background. The opening section, “Glóð,” gradually inches into audibility, finally appearing like a ship coming into view over the horizon. It serves as a kind of overture, with chirping backward voices and bass drones that suggest the textures to come. And it introduces us to the notion that this will be a symphonic record, with just the faintest hint of a rock-band sound.

On albums like “Takk . . .” (2005) and “Kveikur” (2013), Sigur Rós tweaked its approach by emphasizing percussion, adding a communal drum-circle energy to a catalog that often seemed designed only for solitary daydreaming. “Átta,” mostly drum-free and with a winding structure, is 180 degrees in the other direction, and fits more easily in the world of modern classical composition. Sigur Rós zeroes in on its most distinctive qualities and amplifies them to an almost absurd degree. This shift might have something to do with the return of multi-instrumentalist Kjartan Sveinsson, who departed a decade ago. He is the lone member of the group with musical training, and he typically has overseen its arrangements. Here, Sigur Rós has enlisted the London Contemporary Orchestra, with brass courtesy of Iceland’s Brassgat í bala. While guitar feedback, percussion and sound effects appear occasionally, “Átta” mostly finds Mr. Birgisson singing with support from the strings and horns.

Sigur Rós has worked in such a setting before—see “Odin’s Raven Magic,” a piece based on a venerable Icelandic poem—but this is the first album-length orchestral treatment of new songs. “Átta” leverages the large supporting cast for a record with thunderous peaks and lushly beautiful quiet passages. The arrangements sometimes recall the subtle shading and hints of minimalist repetition of Icelandic composer Jóhann Jóhannsson and elsewhere bring to mind Jonny Greenwood’s film scores. But the presence of Mr. Birgisson situates the music exclusively in his band’s universe. The second track, “Blóðberg,” surrounds his vocals with strings that move between just a few notes but modulate from mournful to triumphant via changes in density. On the following “Skel,” the singer shifts to the furthest reaches of his upper range as clusters of dissonance push against his fluttering sweetness. “Mór” adds a thumping bass drum and oceanic washes of cymbals, as Mr. Birgisson’s singing is slathered in an extra dose of reverb.

This is a work that requires the listener to be in a certain headspace, and it’s music you have to give yourself over to. Heard in the wrong setting—a car with the windows open, say—it would come across as not just irritating but also incomprehensible. The little details of the record are where its meaning is ultimately found—the quaking climaxes when every musician is playing at full volume need to be experienced when the quietest passages can also be given full attention in order for their impact to be felt. Sigur Rós is now touring with a 41-piece orchestra, and a seat in a dark theater might be the best possible vantage point for taking in this material; absent that, a comfortable chair in front of a decent stereo that’s been turned up loud has much to offer.

—Mr. Richardson is the Journal’s rock and pop music critic. Follow him on Twitter @MarkRichardson.