Sat on the grass, outside Leeds’ Leftbank venue, the sounds of gentle acoustic guitars wafting out the doors, it feels like the first day of Summer, or the last day of school, which for guitarist Gwilym Sainsbury it kind of is. This week he’s completed his Art Degree.

There’s a relaxed feeling surrounding the band with the unusual name, as they are about to embark on something new. Preparing to leave Leeds behind for leafy courtyards of Cambridge or to chance their arm in the big leagues of London, their final destination is yet to be confirmed. For now though we settle down to the serious business of the science behind their song writing and why they are definitely not ‘geek chic’.

Affable frontman Joe Newman first met ‘Gwil’ in their first year at Leeds University, before joining up with fellow student Gus Unger-Hamilton on keyboards, with drummer Thom Green completing the line-up. Previously playing under the name FILMS, having flirted briefly with the name Daljit Dhaliwal (after the Al-Jazeera newscaster), they only recently changed their name to ∆, which is what you get when you hold down alt and J on your computer keyboard. It follows a series of mishaps leading to them being mistaken for South Carolina garage band The Films, most recently at local festival Live at Leeds.

Gwil shrugs at me, resigned. “We knew that might be a problem long-term,” he confesses, “but when the Live at Leeds publication came out, they’d taken the bio from The Films and put it on ours. I think we then realised that that could carry on happening.

“We’ve always had a bit of a thing about triangles,” he continues, especially Joe. [A love he pays tribute to in ‘Tessellate’, with the line “triangles are my favourite shape”]. It just happened that I was trying to make a triangle on my computer. You press alt-J on the keyboard and you get a little symbol called a Delta sign, so from now on our band name is that Delta sign, but we refer to ourselves as ‘alt-J’.”

I mention the hours, or at least many minutes I spent, tongue between teeth, trying to get it to appear on my lowly PC. Gwil smiles the slightly patronising grin of the knowledgeable. “Ah, it only works on Macs.”

Setting themselves apart from the prevailing local hardcore/metal scene with their minimal style, ∆ are divided by their differing tastes in music. Where they come together is with a shared passion for Radiohead, former Leeds band The Peppermint Lounge and tastes that mix fine art with the more lowly appeal of TV and Film; naming songs after classic thriller Leon as well as ‘The Gospel of John Hurt’, about the unfortunate chap in Aliens who has a creature burst though his chest.

Of these, the most compelling is the heart-breaking fragile strum and stuttering beats of ‘Matilda’, dedicated to Leon’s other main character. “I’ve been heavily influenced by cinema throughout my life,” explains Joe. “I originally wanted to write all my songs about film and have that novelty, but as I’ve developed I’ve got more self-involved and started writing about break-ups and being beaten up. [Gwil mocks in the background, “Boo-hoo!”] So it’s gone down the more traditional path, but I haven’t retired the idea of doing more film-based music.”

Recently they’ve been busying themselves recording tracks available on their Soundcloud as free downloads, as well as spending time in Universal producer Charlie Andrew’s Shoreditch studios and nearer to home at Subpark Studios. Despite all this, ∆ is still very much a “DIY band” that don’t own any amps and often resort to using Thom’s bongos instead of drum toms on stage, and this enforced minimal approach allows space for the intricate, brooding hip-hop beats of songs like ‘Tessellate’ to flourish, with Joe’s voice veering from a dancing falsetto to a bassy rumble. “We don’t have a structural approach to song writing”, explains Gus.

“We’re a bit cowboyish in that respect,” says Joe. “We’re not qualified songwriters, we’re just cowboys!”

With the band’s odd name also comes an odd approach to photo shoots – they insist on not showing their faces.

“When everything’s on Twitter and Facebook… I think it can be more of a powerful thing to hold something back,” says Gus. “We just don’t want to be looking down a lens, leaning against a building. I don’t want to see my face staring out of some blog. That would be horrible!”

Trawling through reviews, the band’s sound has been compared to everything from Wild Beasts and Anthony Hegarty’s dreamy melancholy to Hot Chip style electro ‘geek-chic’. “That was pretty funny,” says Gwil. “Only two of us wear glasses!”

“Yeah, geeks, I’m a jock!” laughs Joe.

Instead, they’ve coined their own terms – ‘jump-folk’ and ‘trip-folk’ – although, even now they are unsure what it means.

Gwil: “When you’re on a train and people ask, ‘So, you’re in a band. What do you play?’…”

“It avoids saying, ‘well you’ve heard of Clap Your Hands Say Yeah, well imagine Thom Yorke and this kind of beat…’” Gus trails off. “It was basically, like, ‘don’t call us a genre,’” he says. “We’ll fuck you up and make up our own.”