The only way to access the flat where the Canadian duo Crystal Castles are staying is by turning left past the white-painted “ghost” bike chained to the railings in memory of a recently killed cyclist, then left again along a deserted alley where crack cocaine users bed down for the night. At 11am it would feel mildly unsettling. At our arranged time of 11pm the mind fast-forwards to some possible grisly outcomes.

The guitarist and synth programmer Ethan Kath – 29, lank molten-vinyl hair – has struggled through a photoshoot which might euphemistically be summed up as tense. “He seems to have a problem showing his face,” murmurs the photographer as we pass each other in the hall. Historically, speaking hasn’t been his forte either. Previous interviews have rarely yielded more than a few consecutive unprompted words from him.

The cynical marketing man in your brain can’t help but wonder if the success of the Ting Tings means that Crystal Castles – also a man and a much younger woman whose combined body language says “item” even if their claims deny it – might yet ride to mainstream glory as a sort of sleazy evil Yang to the Ting Tings’ Yin.

With the insidious electro oscillations of upcoming single, Crime-wave, taking up residency across the play-lists of Britain, that might just work. Here’s the 20-year-old Alice Glass pondering what the happiest moment of her life might have been: “Coming out of my mom’s vagina.” The Ting Tings would never say something like that. And here’s Kath: “I’m at my happiest when people around me are sad.” Having finessed his chops in a Christian rock band, the bloke out of the Ting Tings would definitely never say that.

That Kath and Glass managed to find one another in the sprawling indie scene of Toronto must in itself have been a cause for celebration. Kath recalls that his flat had an infestation of mice, while farther along the same street Glass’s place-was “covered in roaches”. “She had roaches like I’d never seen before,” recalls Kath, while Glass confirms, “I would open the cutlery drawer and they were all in there. You could microwave them and they would survive.”

It isn’t hard to deduce what Kath saw in Glass. At 15 she was fronting a punk combo called Fetus Fatale. “Everything she was doing, I loved,” he says – so much so that he asked her to contribute vocals to some songs that he was working on privately. Kath may only listen to hard-core postpunk music, but perhaps the best thing about Crystal Castles’ eponymous album – released to rave reviews in May – is that you would never guess it. Even on their breakthrough song, Alice Practice, a pop song of sorts can be detected amid a storm of digitised interference.

Success has brought in its wake some unwelcome attention. Over the past year, a bitter dispute has erupted between the duo and the British artist Trevor Brown over their unlicensed use of one of his images – a drawing of Madonna with a black eye – on the sleeve of Alice Practice and a Crystal Castles T-shirt. Kath says that he appropriated an image from a flyer in the hope that its creator would step forward. Brown did, but alleges that he received no remuneration. In revenge, Brown’s side alerted the perfume giant Chanel to the similarity between Crystal Castles’ logo and its own. Alas, it seems that Chanel was so flattered by the association that it took no action.

All of which highlights the unprecedented position in which Kath and Glass find themselves. Somehow, they have become the height of fashion. In an unguarded moment, Glass confesses that it’s something of a “headf***”. By way of illustration, she tells the story of how, while she was on tour with Crystal Castles, she received a call to tell her that, having fallen behind on her rent payments, all her belongings had been removed and left in the front yard. “When I got back two weeks later, I found that the only things that had been taken were, like, the very worst records in my collection. Everything that meant a lot to me was still there – even my lyrics. No aspect of my life proved remotely appealing to anyone in Toronto.”

This ought to be the bit where Kath goes, “ . . . apart from me”, but he has taken to idly piercing a polystyrene cup with a pen. All things considered, we are lucky to have had his attention for the past 50 minutes. Nevertheless, as midnight approaches, Kath allows himself a moment of eye contact and a few words of friendly advice. “If a crackhead attempts to wedge the front door open with their foot, just push them out of the way. They’re usually too wasted to do anything back.” Then it’s back to work on the polystyrene cup.

The single Crimewave is out Sep 22nd on Different. Crystal Castles play the Hydro Connect Festival, Argyll, Scotland, today; the Electric Picnic Festival, Co Laois, Ireland, tomorrow. Jersey Live Fest, Jersey, on Monday, and the Electric Ballroom, London NW1, on Sept 18 (www.myspace.com/crystalcastles)

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