Cat's Eyes live score for The Duke of Burgundy, Brighton Dome

There’s an extraordinary moment, in Peter Strickland’s deeply sensual, desperately funny and feverishly powerful S&M love story, when a camera travels slowly into the darkness between a woman’s thighs. It’s an extraordinary moment in the soundtrack, too. In place of the golden strings and softly hovering choral notes, Brighton Dome suddenly fills with a monochrome electronic pulsing, as if an army of giant moths is flying over with wings of black sheet metal.

Your eyes finally flick back to the other half of Cat’s Eyes. Faris Badwan has spent the performance tucked away behind a synth, silhouette protruding into the right hand corner of the screen like an unruly sign language interpreter. The charismatic frontman with garage goths turned synth pop psychedelicists The Horrors, Badwan is 6ft 6 and stick thin with a front-swept gothic mound of hair. But he’s deliberately shushed in this project, a soundtrack for a film peopled entirely by women.

Italian-Canadian soprano and multi-instrumentalist Rachel Zeffira, Badwan’s partner in his other band Cat’s Eyes, leads an ensemble of 12 women including string and woodwind sections and a small choir. In a comic nod to a scene from the film, the stage is further peopled by shop mannequins. The singers wear feline eye masks and black leather trousers. Badwan just does the leather trousers.

It’s easy to see why Strickland chose Cat’s Eyes to soundtrack his 2014 masterpiece. Badwan and Zeffira bonded, back in 2010, over a love of ‘60s girl groups. Their two albums have been full of cinematic nudges, and their beautiful, guileless melodies often seem to tiptoe over a chasm of dread. Dominated by rich, auburn oboe lines and floaty worldless vocals, the music matches Strickland’s pastiche of ‘70s European erotica with dreamy bucolic folk. Yet, when it comes to phantasmagoric vaginal portals, Cat’s Eyes have the experimental clout to really go there.

As you’d expect from the director of Berberian Sound Studio (whose brilliant soundtrack, Broadcast’s final work, is the most direct point of comparison here), The Duke of Burgundy already has its own potent sound world. This becomes synonymous with the heavy visual textures: sunlight through gauze curtains, piles of autumn leaves in the yard, thickly ruffled silks. Sidse Babbet Knudsen’s Cynthia is an entomologist, and at points she and Chiara d’Anna’s Evelyn sit and listen to the amplified thrumming of moths and crickets. Just as intense are the sounds of a palm sliding up a shining stocking, or a heel pressing into a stiletto.

Cat’s Eyes use individual motifs to heighten the oppressive, all-consuming sensuality of the relationship. Wordless ahs of ecstasy escape from the choir as soap bubbles glisten and pop on a washing bowl full of silk pants. A bassoon creaks ominously as Evelyn opens the wooden trunk into which she will soon be requiring her long-suffering lover to seal her each night.

The Brighton Festival loves a live film score. They play to its passion for cross-fertilising artforms, and have produced some of the most memorable occasions in its history (not least Asian Dub Foundation’s driving accompaniment to the Battle of Algiers.) But original soundtracks, performed by their creators, don’t always make for unmissable live events. The mood here is one of concentration rather than passionate engagement. There are long sections in which the musicians on stage aren’t doing anything at all.

But there is a second, thrilling moment when this becomes a truly live encounter. As Cynthia musters her emotional strength for a final assault on the lover she wishes she could simply cuddle, Zeffira moves centre stage to join the other four vocalists for a stunning requiem. Her voice soars dramatically just as Cynthia zips up her thigh-length boots. It’s spine-tingling in the most complex and troubling of ways.