Sigur Rós, Brixton Academy, London

Jonsí Borgisson of Sigur Rós

Sigur Rós described their last album Valtari as sounding like “an avalanche in slow motion”, which turned out to be a fancy Icelandic way of saying it was like watching paint dry. This enervating record came after a four-year break during which the future of the band was unclear. Their regrouping for Valtari may not have settled the question: in January founding member Kjartan Sveinsson left, reducing them to a trio.

They began the first of two shows at Brixton Academy surrounded by translucent gauze screens upon which abstract patterns and images of dappled leaves were projected. The core threesome – singer Jonsí Borgisson, bassist Georg Hólm and drummer Orri Páll Dýrason – were joined by string and horn trios, a guitarist and a keyboardist. Artful back lighting made the musicians’ shadows flicker and loom on the gauze screen alongside the visuals.

Superficially striking, the effect also gave the inadvertent impression of a cage – as though Sigur Rós had become imprisoned by their distinctive aesthetic. The impression lingered after the screens disappeared. The Icelanders’ contrasting dynamics – choirboy vocals, child-like wonderment, awesome noise – are intended to induce a state of rapture in the listener, but repetition has exhausted these devices. They have become coercive and formulaic.

The first song, “Yfirbord”, a new and unreleased track, was a by-the-numbers exercise involving slow-building ambient orchestration and a walloping climax. It introduced a setlist that tactfully bypassed last year’s Valtari , which was represented only by the somnolent “Varúd”. Older songs were played faultlessly, simple xylophone and glockenspiel melodies swirling into cataracts of guitar feedback and drumming, accompanied by images of mountains, water, stars and people ascending to heaven. A constellation of light bulbs decorated the stage.

There were impressive moments of musical texture, as with the way Jonsí muffled his vocals by singing with his guitar held in front of his face in “Svefn-g-englar”. A breathtaking onrush of sound at the end of “Popplagid”, the final track, showed they can still provoke awe. But awe can be a monotonous emotion: it doesn’t leave room for other responses. It took a pair of new songs to hint at ways that Sigur Rós could escape the impasse. “Brennisteinn” exploded into life with dance beats and green lasers while “Kveikur” replaced rapture with ominous industrial rock and images of 1950s nuclear bomb tests – a more complicated form of awesomeness.

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