In 1998, Simon Reynolds published Energy Flash: A Journey Through Rave Music and Dance Culture. The book began with the birth of Detroit techno, Chicago house and New York garage in the mid-'80s, and traced the music and its many mutations right up to the late '90s. Reynolds presented interviews, personal anecdotes, documentation and critical theory, penning what still stands as the most comprehensive and authoritative single work on dance music and rave culture.

Last month, an updated version of Energy Flash was published, bringing the book up to date with new chapters on dubstep and the more recent explosion of EDM in America. In this excerpt, Reynolds reports back from Hard Summer, the enormous two-day annual festival, which took place at LA's Historic State Park. It had been over ten years since Reynolds attended an outdoor party of this scale in the US, and a lot's changed since the last wave of dance music swept the nation.

Saturday 4 August, 2012; Los Angeles. As I approach the entrance to the Hard Summer festival in downtown LA, I'm confronted by a forbidding black sign. Literally forbidding: it's a long list of restrictions and prohibitions, stuff you'll be frisked for and that'll get confiscated. Alongside obviously illegal things like weapons and drugs, the promoter Hard Events decrees:

• No backpacks
• No dolls
• No toys
• No kandi
• No plush or furry items
• No glow-sticks, light-gloves or other light-toys
• No bandannas, gas masks or pacifiers

These outlawed items are considered unsightly throwbacks to the nineties, with cuddly animals and fluoro gizmos especially redolent of the "candy-raver" stereotype. As the name suggests, Hard is serious about electronic music. But there's more to it than that: the promoters realised that the only way for their company to survive in the face of hostility from local politicians and police was to put as much distance as possible between their events and rave's daft, disreputable past. Some of the banned accoutrements could be regarded as drug paraphernalia: sucking on a pacifier is cheesy and infantile but it was partly adopted by ravers to alleviate the jaw tension caused by Ecstasy, while glow-sticks and light-gloves are for carving triptastic patterns in the air.

Yet once I've made it through the queues, the ID check and the body-search, Hard Summer still looks an awful lot like a rave. Four stages of different sizes are distributed across a long narrow park abutting the overground subway of LA's Metro system. Thousands of people are milling back and forth in every direction, many dressed in outlandish outfits midway between a college fancy-dress party and Willy Wonka. Despite the body-search, some kids have managed to smuggle in candy bracelets, LED-flashing pacifiers and light-gloves. I stare mesmerised for a long while at a Latino girl who's "tutting"—slang for intricate glove-dances done with flickering fingertips. She's tutting for the benefit of a guy I take to be her boyfriend and who's clearly "tripping balls." Blissed by her swirly fractal patterns, he sinks to his knees, looks like he's about to come. But after the private light show, he gets up and darts off without a word—a total stranger, it turns out.

It's a rave, then, but there are big differences between 2012 and 1996, the last time I attended an American outdoor event of this scale. The boys' pants aren't as crazy-stupid wide. And the girls have sexed up their look considerably: lots of Daisy Dukes and bikini tops, even the occasional "Party With Sluts" T-shirt. Some of these college-age and conceivably high-school-age girls look like they've stepped straight out of a Victoria's Secret catalogue. LA nights get pretty chilly but everywhere there's young women in lingerie and little else: white fishnet gartered stockings, bikini tops, skimpy underwear. One girl's wearing lacy semi-see-through knickers with a glow-stick stuck right down her ass crack. That's my take-away single-shot image for electronic dance culture in 2012: the innocence of the PLUR days long gone, the party-hard spirit stronger than ever.

That said, while I come across a fair few people off their faces, the overall atmosphere is less overtly druggy than it used to be back in the day. Maybe people have just got better at hiding it; possibly, the ethos now is to look like you're in control. Yet riding the subway home, it seems like everybody is talking about drugs. "I can't wait to get home and take a hot shower, there's nothing's like it when you're rolling hard," says one teenage boy, who outwardly seems sober. "Makes Ecstasy a hundred times better. Orgasmic." One of his friends boasts about the profit he made buying pills off dealers and reselling them to other kids. And stepping off the train at my stop in South Pasadena, I overhear a girl regaling her companions with a classic "I was so wasted" anecdote: "I got stepped on! My third pill hit me really hard, so I went to lie down outside on the hill. This fucked-up dude trod on me." Pause. "It doesn't hurt though."

During the rave-not-rave itself, I noticed that there's something else different about Hard and EDM, the ungainly term that's now replaced techno and which stands for electronic dance music. Something that's hard to put a finger on. Then I realised what it was: the sound. On a formal level—beats and riffs, the way the music is put together and the way it moves—the music doesn't seem that different from the ravefloor fare of the 1990s and early 2000s, styles like house and trance and electro. It certainly doesn't seem a decade more advanced. What is different is the overall sound through which everything is sluiced: ferociously digital, a flat glare, depthless and dazzling. Staring up at the giant speaker stacks of the main Hard Stage, I suddenly felt like they were iPod ear-buds blown up to immense scale. Partly this ultra-digital aura stems from the gear used by the DJs and musicians: just one DJ worked with vinyl and turntables, everybody else mixed their sets using CDJs or laptops running programs like Ableton Live. But it was also a quality of the music itself, caused by the way it had been assembled, run through effects, subjected to compression (which evens out the dynamic range of the music to make tracks feel super-loud, so that they jump out of the speakers). The result: music like a high definition flat-screen TV, like a 3D- 'n' CGI-addled movie. Monster Energy drink for the ears.

I asked a DJ-producer friend, Josiah Schirmacher, about "that digital sheen," and he said it came from audio software like FL Studio (formerly known as FruityLoops) and Logic, with the latter in particular making "everything sound sort of encased in glass, like it's all been shellac'd." These digital-audio workstations and plug-ins are not the special preserve of EDM, they are the enabling machinery of almost all pop music today. But EDM has special tricks it favours. "That roaring Justice sound," Schirmacher explained, referring to the influential French duo, "is a combination of sidechain compression [that squeezing, pumping sound] and brickwall limiting. It's literally designed to make older people's ears hurt." As a DJ with a lot of experience in Mid-West clubs, Schirmacher associates that post-Daft Punk/Justice sound with cocaine and "study drugs" like Adderall. It's the sound of hyperstimulation taken to the brink of burn-out.

"Digital maximalism" is my term for this zeitgeist-defining sound. Maximalist not just because of the carbonated crispness and burnished brightness, but because of a fussiness and pyrotechnical bombast to the way it's composed and programmed, a quality often redolent of progressive rock and stadium metal. Cutting across many genres, from electro-house to nu-skool dubstep, AKA brostep, to the audio-visual bombast of acts like Skrillex and deadmau5, there's a shared aversion to the very things that characterised analogue-era dance styles: recessive depth to the mix, slow-burning understatement. Every empty space in the audio spectrum is filled up, maxed out.

Digital maximalism is the ultrabrite, NutraSweet, Taurine-amped soundtrack to a lifestyle and a life-stance that could be called NOW!ism. In most dance scenes there's a vein of nostalgic reverence, an in-built deference to a lost golden age. But with EDM, there's just this feeling of NOW! NOW! NOW! And that's the thing I found heartening and refreshing about Hard Summer: the utter absence of any sense of the past being better than the present.