It really activates the nerd pleasure centres to take a front row cinema seat tonight, a kaftan’s-length from the serious kit occupying the otherwise empty stage. Hot knobs lie ready to be twiddled on a console yanked from a Radiophonics Workshop porn shoot. ‘Winter Sun Wavelengths’ reads the big screen. Starting the gig by accompanying a 20 minute film may attract grumbles from the odd sitting prick, but Broadcast collaborating with Julian House of spooked out label Ghost Box makes righteous sense; fellow travellers in creepily beautiful time bubble music, they work together like hot oil on a projector. So the images are all monochrome leafless trees and black and white geometric spirals, the music slow building drones that twist and periodically erupt, cranky hums and spectral wails. It’s all rather swish.

And then suddenly without warning the screen fires technicolour and it’s straight into ‘Corporeal’, three minutes of classic shivering and swaying, Trish Keenan’s instant killer vocals hanging over the picked out bass. It’s a brilliant flush of dark gorgeousness that’s repeated at regular intervals, as songs radiate, fade and turn into the next with little or no gaps in between. I like the uncertainty of the audience: the typically repressed Cardiff response mingling with Broadcast’s web of witchy meanderings, so even ‘Black Cat’ gets gawps not whoops. But check their last song: James Cargill sets off a machine pulse straight from Suicide’s first album, while Keenan picks up a weird, thin electric dulcimer and strums and thrashes it mightily. It’s jangly, fiery robot fuzz and it’s pretty incredible. And then they’re out of the emergency exit while the screen flickers on and on.