6. Valtari (2012)

Absorbed chronologically, Sigur Rós’ output forms a gradual, logical trajectory. From the murky ambience of 1997’s Von to the gleeful, melodic expansiveness of 2008’s Með suð í eyrum við spilum endalaust, each Sigur Rós album builds on what came before it. The band’s sixth LP, Valtari, is their awkward outlier, the stray album that feels oddly disconnected from their previous sonic development. With its glacial drones and repetitive instrumental textures, the music harkens back to ( ) or the moody second half of Takk…. Even the sleepiest moments (the endless title-track, the crystalline drift of closer “Fjögur píanó”) are gorgeous in that reliable Sigur Rós way, and the highlights (the stormy climax of “Varúð,” the tense climb of “Ég anda”) rank among the band’s finest work. Still — especially compared to the rest of the band’s post-Von discography — Valtari is often too precious for its own good, teasing moments of ecstatic release that rarely arrive.