The scene in the Shacklewell Arms is fairly typical of any gentrified boozer in the Hackney precinct, come Sunday night. Soundtracked by the standard medley of 'music for urbanite creatives' (ESG, gangsta rap, Tom Tom Club and the ironic deployment of Lionel Ritchie) grunge-y Courtney Love neophytes talk over the corpses of fey indie boys, who sleep across the mottled leather sofas. A blonde guy, modelled presumably on 80s Val Kilmer, discusses his neck tattoo with a girl in rimmed glasses and granny-chic pants. I overhear conversations about Tumblr traffic and others about vintage tea, and men dressed as Huckleberry Finn play the alpha male in the hope of impressing permanently unimpressed door men. Wan bar staff use their phones while pulling your pint. They are wearing band T-shirts, one of which bears the insignia of stadium ravers KLF, and another a wife beater with punned-on Black Flag bars.

A Northern Irish hipster asks me if I'm in a band. Before I can answer he's showing me an iPhone video of the rock band he's in, and asking me if I know where he can get some 'sniff'. After explaining to him that I don't take heroin, he politely informs me that 'sniff' is street slang for 'Mandy', or MDMA. I suggest that he not ask any of the surrounding woman for 'some sniff', lest it be misconstrued as some kind of kinky sexual request. He laughs hollowly and, now that we're getting on, I ask him whereabouts in Northern Ireland he's from. He tells me there is no such thing as Northern Ireland. What he means is, he doesn’t politically acknowledge the state as decreed by British law.

I tell him that in Belfast it's shitty form to bring up politics with a stranger, and besides, I moved from NI to get away from all that stuff: red faced unionists and seething nationalists, ex-gangsters turned pious religious zealots, Pole-murdering East Belfastians, recreational rioters. I only think this last part though. Before long, the guy confirms that he is, indeed, a die hard nationalist... fuck the Queen, centuries of military oppression, occupied states, Wolfe Tone - all that stuff. I ask him why, if he hates Britain so much, has he moved to the British capital? I'm feeling kind of pleased with myself. It's usually the type of thing I only think of saying about four hours after the fact. I feel like Fred Astaire and smile into my glass. For the first time since we started talking he's lost for words. Lionel's singing "Once...Twice...Three Times..." in the pregnant silence. Crickets can be heard, somewhere a mother weeps. The guy fixes his cap and draws his fringe sideways with all four fingers, with the gentleness you might apply if, it so happened, you were stroking a mouse.

In the land of the contemporary Londonite hipsters, politics is a meaningless gesture, just as a correctly calibrated multi-genre mp3 collection is a meaningless gesture, or a Black Flag t-shirt worn by a slumming faux-hemian sloan. Flaky, baseless posturing is the cultural currency. Not just here, but in the youth district of every large western city in the world. It's all just a big load of FUCK.

As I bid farewell to my friend, Lionel is singing again. This time its "Hello, is it me you're looking for?" I don’t know, my leonine loverman narrator, we're all looking for something, maybe some meaning. I make my way through the back door, past the stairs, through a dark corridor and into the Shacklewell Arms gig room, where things are different.

The first casualty of the post-internet age is tribalism in music. But, in the year that, arguably, rave finally broke in America, lines are being drawn anew and a generation gap has opened. Uniting the diaspora from a host of fading, increasingly marginalised ideologies - emo, metal, punk, rave – EDM has brought to bear a single homogenised front. The genre and its figurehead Skrillex appear to have given the American kids some cultural meaning - 'meaning', that is, based not on a fashion trend or a consumer choice, but on a type of music, perhaps for the first time since grunge. To the excited teens in Shacklewell's back room bar, EDM is an identity, a tribe, an ethos, a culture and a lifestyle.

Travelling straight from his headlining set at SW4 festival, where he played to 10,000 revellers, Skrillex is bestowed a hero's welcome as he snakes through the Shacklewell's tiny crowd. Taking his place amongst a horde of flunkies and local DJs on stage, the diminutive Corey Feldman look-a-like picks up from bashment act Extra Style, ripping into the transition track without missing a beat. After exchanging a final set of of awkward b-boy pleasantries with Extra Style's vaguely embarrassed MC Samurai, he sets about reassembling the dancehall track from the ground up. From here on in, it's 100% shock and awe.

On the evidence of tonight's set, EDM is not dubstep, not even in the post-Coki model. It's no more dubstep than grindcore is rock & roll. It's a separate entity in itself, even if its basic components are uniformly familiar. What it is, essentially, is a bit of everything. Generally speaking, it's electronic dance music, period. Which is to say that the 'EDM' moniker is a legitimate way to define an ill-defined sound, rather than the cynical rebranding of dance music for Americans who'd never heard of Europe before the Da Vinci Code. Ill-defined or not, though, what a sound it is. On wax it's anathema to fans of what you might classify as 'headphone-oriented' dubstep, and rightly so – this year's Bangerang EP is a textural wasteland of midrange compression and tinfoil FX, conjuring a depth of field that's about as 3-dimensional as a Spice Girl. But in a live setting, all the record's worst traits work to the show's advantage. In a 20,000 seater stadium - the kind of place that Sonny Moore is used to playing these days - the sound assumes the form of a marauding 400-foot high leviathan; a bit like in that hologram 'Vrs' scene in Scott Pilgrim Vs The World, in terms of sheer neon spectacle and bass-busting power (incidentally, there's something very gamer-friendly about Skrillex). In a 200-capacity den in East London, however, it's outright violating. The pressure on your body is terrific. Within an hour you're neurasthenic with tiredness. Within two hours your hands shake when you go to pay the ravaged barman. After three hours there's a lobster trap full of broken glass where your guts used to be. By the end you're made entirely of wire wool.

It's not the speed, exactly, that's so devastating. Similarly intense dance genres like hard house or breakcore, for example, will easily outrun sets like these. Rather, it's the sheer volume of events, rather than sonic detail, that leaves you ragged. There's no such thing as a 'build' in live EDM, only the lateral movement between climax and near-climax, between which two points resides an embarrassment of money-shot hooks - the arrival of a new beat, a new synth melody, a new electro modulation, a new rap, a new vocal, a new anything. And without an inch of fat around the flanks. It's the perfect machine, optimum efficiency, a new delivery method for total and perpetual gratification. Quite frankly, the impression given is an awe-inspiring consolidation of years of post-rave party music. Every known cheapjack event from every known sub-genre is co-opted and redeployed at a dazzling rate of frequency: trance drum-rolls and French house filters, buzz-saw electro synths and rave's pitched-up vocals, the sledgehammer beats of boom-bap, Lex Luger synths, techno drops and scores more. It's utterly disposable, facile, faceless, rootless and meaningless, and utterly impossible to resist in it's live form. All things considered, however, the secret to EDM's success will forever be the bass. Far exceeding anything wobblestep ever produced, both in terms of technical sophistication and multi-functionalism, the bastard thing simply drags your mind's eye in and around, back the ways and over. It's made from gunshots or voices, masticated beats or lasers, or some unknown ingredient. It lands on your sweet spot every time and can either electrify a punk moment or catapult a dance beat. It's the pitiless God that reigns supreme in the EDM universe.

There are, theoretically, several precedents to the physics of Skrillex's sound. You take a bit of Vitalic, then add a dash of Daft Punk's 'Harder Better Faster Stronger'. Season with crunk's in-the-red energy levels and brostep's metal-on-bone gait, then supercharge with Michael Bay's approach to understatement and the sound of his Transformers transforming. What you've got is the Red Bull-guzzling Godzilla-vs-Las Vegas sound of EDM. Now imagine you're an American teenager, whose only previous encounter with dance music is that 'ardcore song they play at football games. Imagine how it must sound to them. It's no surprise that American youth have adopted him as some Neo-like messiah of futuristic punk. Tellingly, it's the industrial-goth subculture that has received the biggest shot in the arm here - Skrillex's popularity amongst the Cyberdog set is all consuming.

What's immediately apparent tonight is EDM's nu-metal influence (Skrillex is a massive Korn fan) - a genre which took a similarly trite approach to song construction, with its formula of 'pumping punk/urban bit' > explosion of lumbering machine-backed heviousity. Indeed, you could argue that EDM is the ultimate dance-rock hybrid. However that be giving short shrift to one element of Skrillex's sound that's so often overlooked: the funk that guides the rhythms. The tracks hewn here from his recent house-informed albums are rudely danceable. On the other hand, equally overlooked is the IDM influence that pervades here (Moore is also a massive Aphex Twin fan). Although lacking in IDM's mind-blowing beat science, several times tonight the tracks teeter on the brink of rhythmic dysfunction, sputtering brilliantly in labyrinthine clots of industrial cross-hatching. 

Tonight's set is London-tooled thing, full of UK bass tropes and ragga flourishes. It lends the sound an earthy feel, offsetting the aesthetically horrifying arrival of auto-tuned male emo vocals, indie synths and electronic pop-punk – practically the most numbingly plastic sound ever conceived. Mostly, though, it's a stern, unsparing set which extracts every particle of energy from the low-ceilinged room. The game is called survival, and with so many competing teen subsets and cultural factions there are bound to be a few differences of opinion when it comes to dancefloor etiquette. I watch from the safety of a 7ft amp side-of-stage (looking for all the world like a lurking Scooby Doo villain) as an awkward teenaged boy, dressed as Skrillex with shaved hair and black rim glasses to boot, stands a foot away from Moore, not dancing but staring - flipping out to be in such close proximity to his idol. His only obstacle to fanboy nirvana, however, is the cluster of dolly birds tearing it up to his right, one of whom seems hellbent on dislocating the goth's left hip with her rear end. Her gyrations continue until I suspect she is taunting him intentionally with her suspiciously well-aimed butt shots. Soon after he begins the fightback with some equally hostile ass work. In no way is this erotic.

Elsewhere, a gang of Asian boys throw massive leg-wobbling shapes, to the chagrin of those perched on a nearby shaky amp, while quite suddenly a grebo-looking kid decides that there's to be a mosh pit. Literally, he shouts "mosh pit", and one appears as if by magic. It's ace to watch, until a flaxon-haired weightlifter strays too close and receives an elbow to the ear for his troubles. He shakes it off, but when his girlfriend comes in for some bumping he loses it, flinging an unlucky mosher into next week. Add to that the clandestine smokers, taking their cues from the perma-puffing Skrillex himself, and what you have is a surefire recipe for a nicotine cold sore. None of which makes one iota of difference to the couple necking serenely, dead centre of the morass.

Roughly 50% of the set is handled by Skrillex's mate, a big farmhand-looking fucker with nimble fingers by the name of Flux Pavilion. Someone shouts "You're a crap Pavilion!" which doesn't make sense and is very funny. But he's not a crap Pavilion - if anything he's a very good one. 23 years of age, the blonde lump is every bit as able to jackknife the front row as his teeny and very rich sweetheart (they whisper in-jokes to each other throughout). It would be touching if your jaw wasn't wired shut with newly conjoined fillings, or had you not been rendered cross-eyed by the '3D lighting' bulbs, truly the strangest effect to have ever bathed a dancefloor.