It’s a Monday night in south London, and the crowd at Omeara is going absolutely wild over a vegan experimental jazz band. One saxophonist looks like he’s on loan from a metal band, the other fixes his stare on the crowd with the intensity of a rapacious shark. The raucous 90-minute set comprises a single song with a killer hook.

Moon Hooch started as buskers in Brooklyn, until the NYPD banned their shows as a public order hazard. Drummer James Muschler remembers: “We were playing at this train station until late, and hundreds of people were flooding in, not taking the train and staying and dancing. When we got banned we just went to a different station.”

After a spell organising illegal raves, since 2013 they’ve released four albums and gained a cult following, performing sold-out shows around the world and attracting more than 2m YouTube views for their concert in National Public Radio’s Tiny Desk series. On his 6 Music show, Iggy Pop said: “I’m telling you these guys are cool.”

By rediscovering the joy in music, I started revisiting jazz in a more playful way

Although they are often billed as “techno-jazz”, a more accurate description would be, according to saxophonist Wenzl McGowen, that Moon Hooch “are jazz musicians, but don’t try to play jazz; this is our take on playing acoustic techno”. There are also occasional forays into metal and hip-hop, and Muschler takes inspiration from classical Indian music. At one point they fit a specially customised traffic cone to a saxophone to create a bass sound: “The longer the tube is, the more air resistance there is, which in turn makes the reed vibrate slower,” explains McGowen.

The three members of the band – the third is saxophonist Mike Wilbur – met at the prestigious New School for Jazz and Contemporary Music, where they practised from 8am until late at night. (They are, incidentally, not big fans of the film Whiplash: “I felt the drummer was not in it for music but for his own ego,” says Muschler.)The jazz scene, which originally rejected them (“what we’re doing is so far out of the box that even very open-minded jazz musicians sometimes frown upon us,” says McGowen), is starting to come round to their unique sound: a recent London Jazz News review praised their “total commitment, musical virtuosity, wall-to-wall grooves – and a good time”.

McGowen says: “It’s surprising that you leave a scene behind, do your own thing, and then suddenly that scene wants to integrate you again, because it ends up being an innovation.”

Underneath the party tunes and traffic cones, the band have consummate technical skills and a firm grounding in musical theory. Muschler speaks with authority about the ways Schoenberg’s ideas on atonality can relate to dubstep, a sound McGowen recreates using the contrabass clarinet because of its “odd harmonics – it pretty much sounds like the screeching bass you would hear in Skrillex, so it’s pretty cool to be able to do it organically”.They also use “unique tongue techniques” to make saxophones sound more synthesiser-like.

Although jazz school inculcated them with discipline and perfectionism, a fair level of neurosis crept in as well. “It’s an interesting balance, because to improve you need to judge yourself, and then to perform you need to let go of that judgment,” says McGowen. “For me, it became very intense,where I would view music competitively, almost like a sport. I got to the point where I lost the soul in music; I was no longer enjoying it.”

Luckily, techno came to the rescue. “People are just listening to it to dance and party, and that attracted me. By rediscovering the joy in music, I started revisiting jazz in a more playful way.” Although their days of illegal raves are behind them, McGowen adds: “We’ve definitely stuck with the underground, raw energy feel. We want our shows to be crazy dance parties.”

Moon Hooch’s Live at the Cathedral (CD & DVD) is out now on Hornblow. They will perform at Devon’s Beautiful Days festival (18-20 August) and at Under the Bridge as part of EFG’s London jazz festival on 16 November