For five minutes it continues to happen. Then it carries on happening some more. Further time passes. The Sound - to which Swans once composed their own worshipful dirge – carries on failing to stop: a draining, droning, dizzying buzz which may or may not carry within it an infinite register of sub-drones. It's hard to tell. A ripple of discomfort passes through the stalls at Koko. Some of us have done this before. Some of us, clearly, have not. The band ain't even appeared yet but down the front they're covering their ears. I know. I'm down the front. Anticipation at the arrival of Swans – reactivated after nearly fifteen years – devolves into genuine, jittery anxiety. It cannot go on. It goes on.
It's an uncompromising statement of intent from a band whose music has always been a physical force, made not merely to be heard but to be felt, in (and with) every sense. Eventually a guy called Thor makes his way on stage and rings out a peal of tubular bells. He's followed, quite a long time later, by Michael Gira, looking these days like a well-fed William Burroughs. No Jarboe to lighten the load this time, just Gira gesturing mysteriously over his guitar as if summoning something elemental from the earth beneath Camden Town. It builds into an insurmountable wall of noise and every brick is the size of a house. If you'll pay good money for crushing, aural catharsis – and casting an eye round Koko, some of us evidently need it bad – then here is the right place to be.
So what are the reborn Swans about, here in the homogenised, digitised, twenty-first century? Back in the early 1980s they pioneered a new form of strident, punishing, industrial noise. Their constituency was mythically barren and their concerns were kinda sick: here be degradation, misery and ruin. Filth, A Screw, Public Castration Is A Good Idea - these were truly the (de)basement tapes, a final outpost on post-punk's rim where, to borrow from Swans' spiritual brethren Killing Joke, all that remained to mine were Extremities, Dirt And Other Repressed Emotions. Back then they dealt in an aesthetic even more brutal and joyless than Crass; sometimes that's precisely what you want to be aligned with.
After that came the apocalyptic folk - a dirge-driven, blues-inspired songbook that seemed to draw equally on Johnny Cash and Wagner, mysticism and machines. Throughout the late 1980s and early 1990s Swans created a series of monolithic, melancholic masterpieces – stern and droning in their obsession with faith and frailty and yet, with their oceanic swells of noise, exhilaratingly exultant. For Swans it was always The End but the music was weirdly rapturous. While their progeny - Ministry and NIN - mutated into a bad Mad Max cartoon, Gira was out there in the hinterlands creating his eerie, sombre laments, post-punk's own Harry Crews.
Then came the actual end. I saw what was billed as Swans' last ever gig in 1997, a vast blast of noise at the much-missed Astoria. Gira and Jarboe parted to pursue other, less draining projects. Gira gave us Angels of Light and freaky little Devendra Banhart. Jarboe's eerie take on raga blues at the Scala a few years back remains one of the witchiest gigs I've ever seen. Whatever. Swans were dead. Life went on. I missed them because they kinda helped.
But back to tonight. Among the slightly creaky industrial types, the weathered punks, the culturally curious and the greying fortysomethings who probably haven't always looked like that, is a smattering of skinny hipsters in clingy jeans and fluffy moustaches. Hard to tell how they've found their way here. Banhart may be involved. The Guardian has interviewed Gira. Whatever the hell this band is about now, this evening qualifies as an event.
And so it is, but not in any conventional sense. Swans are capable of making music harder and more cripplingly intense than any other band on the planet, but this is rock shorn of its theatrics, stripped of its behavioural codes. On the US leg of the tour, Gira waded in and stopped some kids from moshing because he thought it an inappropriate response. Just what sort of response is appropriate to this music is hard to say. Its size is epic. The volume is cosmic. Swans still demand utter submission. When Phil Puleo starts working that side-mounted, Taiko-style bass drum, it's as if Swans have strapped a stethoscope to the side of a depth charge and plugged the earpiece into the back of your brain.
That's the physical assault and it reorders your internal organs. But this is also strange and uplifting music, infinitely mysterious, mysteriously celebratory. Power – an issue about which rock is peculiarly ambivalent - has been an abiding obsession for Gira – having it, losing it, suffering it, abusing it. This band's myth casts this music as relentless and brutal but - paging Dr Jung - it's the feminine surges and cycles through which the power is transported. Whatever it is that this band are about now, they're still taking anger, impotence, doubt and disillusion and transforming them into some kind of immeasurable, indescribable energy.
Later, out on the street. Dazed and deafened punters drifting slowly away. Want to know what we've just witnessed? White Light From The Mouth of Infinity.