Call Sigur Rós the Mark Rothko of music: they have the power of abstract painting.

Jonzi sings in a mixture of made-up language Vonlenska, Icelandic (native speakers 330,000), plus snippets of English.

The long tracks of atmospheric melancholia, made using a bow on a guitar, pull the imagination and the heart left and right, and refuse to settle on simple melodies or straightforward lines.

Yet the Icelanders connect to stadium audiences – because, like abstract art, raw emotions transcend other barriers. It’s not what you say, but how you say it.

There is no doubt the material from seventh album Kveikur has been written with bigger arenas in mind. For it was when a giant gauze sheet fell – with the band holed up inside amid projections of bodies, faces and webbed mazes of colours – that drummer Orri Páll Dýrason unloaded a straighter beat and Jonzi’s voice dropped to a lower register.

Things suddenly sounded almost industrial, the eerie sound of screeching in a warehouse.

The new material might swirl round arenas easier but is no more powerful than early soundboards such as Ágætis byrjun.

Indeed, the finale was worth the entrance fee alone. First Jonzi sang alone, holding a note for what felt like an hour, before dedicating an intimate acoustic version of Ágætis byrjun, not played since 2007, to Brighton’s FatCat Records (the band’s early label).

Popplagið, its colours applied gradually, layer by layer, was a masterpiece of execution and restraint.