The idea is that you don't enjoy a Sunn O))) concert so much as endure it; don't go to one so much as undergo one. Even calling it a concert feels like an undersell— its more akin to an experience, or a ritual.

The trouble with this is that it's all just too much fun. From the moment that Mayhem singer Attila Csihar steps out on stage to begin a strange, chanting vocal performance, before being joined by five robed and loud instrumentalists, all the way through to an ending that sees him writhing on the ground decked out in a gown made of mirrors and headwear full of protruding spikes like a deranged Statue of Liberty. It's joyously ridiculous, absurdly brutal — and, above all, good fun.

Artful noisemakers Sunn O))) are perhaps not best known for the quality of their sound as the quantity of it — the band's catchphrase, 'Ever Breathe A Frequency?' — is a reference to the fact they are, above all, just incredibly loud.

But all of that overlooks the fact that band's work is incredibly disciplined, often intricate, and focused on shaping and sculpting, not just building, that huge wall of noise. It's fitting that the night happens at the Barbican, with all its finely designed size; Sunn O))) are architects, not bricklayers.

Often forgotten too is the band's showmanship, in the more traditional sense, perhaps because the real stars of the show are the legions of amplifiers arrayed at the back of the stage. The music might be loud, distorted, slow and largely static, but live it is given urgency by the slowly ascending fog, pulsing lights and the strange movements of Csihar. He provides chilling chanting at the start, and outright horrifying screeches and screams by the end; but his job is also something between dancer and conductor, too, and for much of the concert he doesn't sing at all, waving his hands around and eventually returning for the end in his strange, thorny-headed outfit with lasers strapped to his hands.

The rest of the band are less obviously showy, skulking around at the back, but that doesn't mean they have less to show off. Joining the band at the Barbican and playing on her own as support is Hildur Guðnadóttir — an Icelandic cellist, though "cello" feels like a word not really up to describing the deformed and supplemented version of the instrument she plays — and along with the rest of the band Hildur helps provide noise that is subtle, complex and transfixing, even as it is thrillingly loud.