Otherworldliness has always been Sigur Ros’s stock in trade from the band’s impossibly lush soundscapes to singer Jónsi Birgisson’s impossibly gorgeous falsetto. The language barrier helped too — singing in a mix of Icelandic and Birgisson’s own gibberish tongue made it easier to believe that the band emerged from some distant galaxy or higher plane. That started to change with “Gobbledigook” the highly percussive first single from the band’s 2008 full-length. Go Birgisson’s first solo album continues to bring him down to earth.

“Go Do” and “Animal Arithmetic” open the album with a relentless drive and overflowing optimism the first seemingly cobbled from the same sessions that produced “Gobbledigook” the second borrowing the pulse of Birgisson’s recent collaboration with über-DJ Tiesto. As the album progresses Birgisson moves closer to traditional Sigur Ros territory but the string and horn arrangements from neo-classical wunderkind Nico Muhly keep things decidedly earthly — flute trills echo bird calls piano flourishes recall rustling wind or roiling waves.

The majority of the album is in English — a first for Birgisson — but it hardly matters as the singer’s voice is often as indecipherable as it is gorgeous. In other words don’t worry about Birgisson becoming just another singer-songwriter; it’s more like he’s transforming from an angelic spaceman into a wood nymph.