On Thursday I caught the Crystal Castles live at the Enmore Theatre. I had been keen to witness the Castles phenomenon in person. I was randomly given their debut album by a friend a couple of years ago, and I found its lean and mean Casio electro-noise and oddly beautiful melodic hooks so refreshing, cutting right through the more cheesy and pretentious elements of electronic pop like a hot knife.

I became kind of obsessed with it. And apparently fans all over felt the same way, because it sold heaps and the Castles became a commodity. I had no idea what to expect from the show, but I learned quickly just how much excitement they generate.

It was a hot night; the Enmore was packed in with kids who were clearly up for it. By the time the band hit the stage, the place was sweltering. But the crowd was really going for it; after a certain point, I don’t think anyone cared how sweaty they were: they only got louder and more involved as the show went on, and the Castles deflected the energy, setting off one furious storm of noise after another punctuated by flashing strobes, like a sudden squall on a humid summer’s night.

To be honest, I was a little surprised at the make-up of the crowd. If I looked only at the screaming masses of youth, I felt like I could have been at a show that was a good deal more pop – I dunno, some new R&B diva or something. But looking back at the stage confirmed I was witnessing something edgy and a bit challenging.

I was puzzled, but also psyched. I’m still surprised when underground sounds go mainstream, as if I’m suddenly realising the paradigm has shifted on me again. “Oh, you didn’t know pop these days is noisy and kind of weird?” I wondered about the Castles’ appeal: do the distorted 8-bit keyboard bursts make sense to a generation weaned on cheap PEDs? Do they identify with singer Alice Glass’ unbelievable success story – from teenaged runaway to pop star practically overnight? Or is it her riot-chick charisma?

Whatever, they were into it, and frankly so was I.

The Castles didn’t bother with between-song banter, nor with long intros nor slow jams; the stage set-up and light-show was minimal, the set-list brutally efficient and satisfying. The static and squeal of some of the older jams like Alice Practice got heads nodding and shaking, before dark, danceable jewels like Crimewave and Air War were met with a roar of approval and got the place in gear. But the more ethereal and dramatic sound of new songs like Baptism may have moved them even more.

Ethan Kath, glued to his keyboard, hid under a hoody, looking like a Star Wars fan-boy or an amateur bank robber. He unleashed powerful bursts of body-rocking beats, going right for the gut, sometimes sharp, sometimes grimy and distorted, and wickedly fun, as if gremlins had highjacked Autechre’s gear. Every so often a bright Kraftwerk -like keyboard melody would appear in the mix like sunlight glimmering off the shards of sound.

A drummer backed up the electronic tracks; I couldn’t make him out very much, but it added to the rugged live feel of everything. Enhanced by the theatre’s carpets and high ceilings, it was a loud, aggressive sound but still balanced and good for sweaty dancing.

Alice Glass’s performance was really something. Stalking the stage like a slender, leather-clad ghost (maybe the ghost of Karen O?), she didn’t smile or say anything, only pouring herself completely into her vocals. Sometimes her punk-rock yelps came through loud and clear, calling the crowd into a frenzy; other times all of her clenched efforts merely produced an industrial hissing squeal far down in the mix – only adding to the haunted effect. There was no making out the lyrics; this was body music from a broken body.

She was on crutches – she’d broken her ankle in Japan a few days earlier – and I can’t say enough about how this added to the show, watching this busted girl howling into her mic, limping around, waving her crutches at us desperately. Was she brave or stupid, climbing onto the equipment, teetering on one leg like she wanted to jump? It was like watching some kind of performance art about pain and brutality. It made the angst seem real, not a game, and heightened the frail beauty hiding behind the cloud of noise.

Her charisma was a lightning rod for the crowd, who followed her every move and matched each hoarse shout with their own. The encore of Untrust Us was not enough and they were disappointed when the lights went back on and the storm was over. Kids these days.