Here's something you won't read every day: Ethan Kath from Crystal Castles is an extremely nice chap. If you've ever read anything about the world's new favourite Toronto-born electro duo, Kath is always – but always – presented as a grumpy, uncommunicative, passive-aggressive arse.

If "new rave" brought them to our attention, Crystal Castles have long since outlasted it. Masters of what has become known as 8-Bit, or Chiptune, Crystal Castles build brilliant records from sounds you might find down the back of a games console. To date, nearly 8 million have watched five different Crystal Castles videos on YouTube; this is a band so of the moment they've been on the soundtrack to Skins more often than a squeaking bedspring. They are this generation's chemical brother and sister.

Anyway, there's nothing even slightly grumpy or uncommunicative about the 28-year-old in a black hoodie and skinny jeans I meet in the banana-yellow offices of a 1,000-capacity nightclub in an unattractive suburb of Milan. He apologises for his hair being odd lengths (apparently Castles screamer Alice Glass cuts it when he's not looking). He tells me about the livestock and lack of windows on his grandfather's farm in Calabria (the southern-most "toe" in the Italian "boot"). He tells me about the band's old van (a decommissioned riot squad vehicle with "stab-proof" tyres) and how he had to get rid of his first drummer when the tub-thumper's ruinous liking for cocaine derailed a huge show in Tokyo. He tells me about how many links to illegal downloads of his new record there are on Twitter. He tells me about how those links all lead to a version of the album that includes the wrong edit of future single, Celestica. He has a lot to say for himself, all of it interesting, and each story is delivered with the same engaging, garrulous enthusiasm. When he offers to nip out and chase up Glass – she's having a shower, having just woken up at 6.30pm – I think to myself what a pleasure it is to meet him.

So Glass appears, hair still wet, beaming smile, couldn't be more charming, and we sit down for the interview. Then something sort of hilarious happens. Ethan Kath slips into character and becomes "Ethan Kath out of Crystal Castles", someone who is, oh dear, quite capable of being a grumpy, uncommunicative, passive-aggressive arse.

I lob an easy one at him to start. Tell me about The Brain, I say, referring to the battered flight-case full of wounded, half-dead keyboards and old mobile phones that, apparently, provide a lot of the noise and vocal samples that the band use on stage.

Crystal Castles first album cover.

"There's no such thing," he replies with a face like a four-year-old who's just been denied a lollipop. And we're off! "Maybe the crew call it that," he says, "but I don't. I'm not emotionally attached to any gear."

So if it all got burnt you wouldn't care?

"There are music shops in every city in the world," offers the man who has built a (well-deserved) mythology on the uniqueness of his sounds and is famous for his hatred of preset technology. "It's no big deal."

In an attempt to tease Friendly Ethan back out of the woodwork I go for the least contentious question imaginable. Do your fans react differently in different parts of the world, I smile?

"No," he says, staring. "Everywhere hates us the same." Except, of course, they don't. Outside this venue there are hundreds of young (and not-so-young) fans gathered hours before the doors open, and that's because Crystal Castles' new album – called, like their first, Crystal Castles – is a wonderful record that rides the noise/pop knife edge as well as anyone in the world. Kath is a songwriter and producer of rare talent, someone who can write songs like Celestica or Year Of Silence that are so brilliantly melodic, so grippingly immediate, so joyously pop, that were they on the new Kylie Minogue album you would throw your hat into the air with the slightly edgy electro pleasure of it all. But he can also write Doe Deer or Birds, pieces that are furious, experimental and abrasive. I Am Made Of Chalk sounds like he's shredded a VHS copy of infamous video-nasty I Spit On Your Grave and randomly stuck the bits back together with home-made adhesive. It is both brilliant and terrible. Kath is taking chances, and we are lucky to have him. He may, in fact, be the planet's funniest hipster. I certainly found him highly entertaining, I just didn't see the point of the sudden grump attack.

When Kath and Glass talk about how they came together as Crystal Castles in the summer of 2005 the room actually comes alive.

"She was getting high all summer," Kath laughs. "I found her on the street; she was higher than anyone I've ever seen in my life." It's worth pointing out that, at the time, he was in a band with a heroin addict. As a child Glass had been a real loner: someone who sat in the corner of her room and wrote "cheesy" poetry, who ran away from home at 14. When she began recording with Kath she was just 17, had shaved off half of her hair and completed her look with a filthy eye-patch.

'We have no ambition. There are 3,000 bands that deserve this more than we do'

"This punk guy had the infection first," she smiles. "He then went around dabbing his germ-stained finger in everyone else's eye. I had it for three months."

Kath says she was so high that when he wanted to talk to her about the songs they'd recorded together Glass would just say, "Call me!" and make the phone-to-the-ear movement despite the fact that neither of them had a phone. They still don't, apparently. Glass was living with a squeegee merchant called Rosa who had a house in downtown Toronto and split the rent between 20 people at $100 a month.

"There were a lot of drug punks there," she says. "They'd do really shitty things like heat up metal coat hangers and brand their skulls … "

It seems like everything's back on course, so I mention that what I really like about the record is how it goes noisy one, pop one, noisy one, pop one. That's great sequencing! Silence. I move my feet to allow a huge ball of tumbleweed to blow past.

"Maybe," says Glass, eventually.

"I don't hear them as noise or pop," Kath says. "All I hear is one bleak feeling that lasts an hour."

Indeed. But Year Of Silence is a big, bright brilliant pop song, I say. It doesn't sound particularly "bleak". Interestingly, this may be the exact point where the ghost-like presence of Nice Ethan rises up from his mortal frame and boards a transatlantic flight back to Toronto.

"That's actually insulting," he groans. "That's the opposite of what I was going for. I'm not trying to write pop songs at all. Year Of Silence was something I imagined hearing at some shitty, small goth club."

Crystal Castles second album cover.

The duo are playing all over Europe on a pre-release tour for the new album, which is coming out on the same label Snow Patrol are signed to. They've played an NME tour sponsored by Topman and they're appearing at the Radio 1 Big Weekend. Are these really the decisions of an unambitious band?

"Yeah," mutters Glass.

"Of course," says Kath. "Because we have no ambition, yet we are in this position. There are 3,000 bands that deserve this more than we do."

No there aren't.

"You don't need ambition to play a show," says Glass. "There's not a lot of effort needed … "

Two hours later and the venue's full to bursting with goths, metalheads, indie kids, ravers and whatever the Italian equivalent of mainstream, gig-happy teens are called. Crystal Castles' live show is a masterpiece of dark beauty. Lit by a pair of brutal strobes they stick to the big-room tunes. Glass twists and dives and crawls along the stage hugging a loose strobe to her belly. She is utterly captivating.

Kath stands to her right, behind what looks like it might be The Brain (except, of course, that doesn't exist), alternately punching out notes and beats, then strapping on a guitar. Crystal Castles are awesomely concise and effective, a rolling noise that will destroy all competition at any festival this summer.

A couple of days later I email Kath to find out if his rather taciturn interview persona is actually all part of some larger Crystal Castles gameplan. A self-preservation technique perhaps? A perfectly charming email pings back within the hour.

"There is no other person," he writes. "We're quite shy."