Takk ..., the band's fourth full-length, is less focused on the dark side of the emotional scale and moves from wails of despair to exaltation. "Glósóli" tinkles and glimmers for a while and climbs toward a wall of noise accented by a thumping drum that is rock music's spiritual equivalent of speaking in tongues. "Hoppípolla" crescendos into romantic strings, ending with horns, and Jon Thor Birgisson's high choral harmonies warm up "Sé Lest," which somehow turns to a brass band without even the slightest hitch. In the middle of "Saeglopur," a piano hits minor chords that set off drums and a droning guitar--when the floor tom and the bass drum begin pulsing in synch, the songs on Takk ... become aural catharsis. While previous Sigur Rós albums played like the soundtrack to curious, and oftentimes haunting, dreamscapes, Takk ...'s exuberance lends itself to the kinds of dreams where you're flying over pure green landscapes and clear blue oceans.