Having cruelly teased us with last year’s live album Inní, Iceland’s premiere post-rock outfit are back with their first fresh set of material since 2008. Valtari marks a move away from the relatively “pop” aesthetic of Með suð í eyrum við spilum endalaust, with the symphonic rise and fall of Jónsi’s ethereal voice variously magnified by devices like reverb-laden guitars and discordant musical boxes. Instrumental tracks are equally entrancing, with the hypnotic sprawl of ‘Fjögúr Píanó’ and the pulsating electronics of ‘Varðeldur’ showcasing Sigur Rós’ varied musical vision and impeccable grasp of dynamics.