Leave it to Hype Williams to announce their London gig to launch new album Black Is Beautiful mere hours before the event and at a tiny venue, prompting a scramble for tickets and a tight squeeze into a very warm basement. But if Dean Blunt and Inga Copeland have proved anything over the last couple of years, it's that they're protective of their music in the extreme, with Blunt even going to the lengths of (perhaps rather disingenuously) claiming that he's "not smart enough" to be putting deep thought into what they do. As if that notion hadn't already been disproved by everything they've done over the last couple of years: last year's lovely, ecstasy-addled hip-hop tryst One Nation; an immersive takeover of dubstep crucible Plastic People last March, just as enjoyable for the presentation - poised at the halfway point between gig and installation - as for the music itself; signing to Hyperdub, whose reach has dramatically increased as of late; Copeland's self-titled 'solo' EP, which found her adapting well to desaturated pop songs.

Then there's Black Is Beautiful itself, their most thoughtful and subtly political statement so far. So whether or not Blunt actually feels like his music is devoid of meaning beyond the immediate - we're going to presume he doesn't - he's going to have to try a whole lot harder if he doesn't want people to take it seriously. As it stands, even the stuff he and Copeland churn out in their demo sessions - recent 33 track hard-drive dump The Attitude Era - offers rich pickings, both purely on a sonic level and for those who've been enjoying their more thought-provoking forays into blunted dreamworlds, half-sleep states and lo-fi AM radio pop.

Then there's tonight's performance. Blunt and Copeland are holding court downstairs in dreadfully named Dalston venue Power Lunches, where the basement room is sealed off from the outside world by a double set of doors, and pumped so full of dry ice it's tough to see outside a three or four foot radius. The ceiling is low, and the air is pillowy soft with smoke and sweat steam. The small space is battered by lurching salvoes of sub-bass; apparently the soundsystem they've purpose installed for the evening is twelve times the power of the venue's own system. The room's only light source is a single, blindingly bright LED lamp over the mixing desk (and the odd flicker of strobe from the stage), staining people nearby a wan, sickly sort of hue. There's a tall guy stood a few feet in front of me, close-cropped hair tucked under baseball cap, arms wrapped around his midriff, rocking in a slo-mo skank. Many of the extended Hyperdub family are in attendance. It feels awfully familiar in here... Ah, yes, of course: it feels just like Plastic People used to at FWD>>, before 2010's dubious local council intervention and last year's soul-sapping rearrangement. The only thing missing is the sharp hum of weedsmoke that used to billow outward from smokers' corner.

Last year's show in Plastic People - before the refurbishment - was an affirmation, indicating that the duo were poised to become truer inheritors of dubstep's crown than any number of paper-thin bass music pretenders. This evening hammers that point home harder still. Its one constant is sub-bass: a hot and volatile flood that corrodes through everything else they throw into the mix, prone to switching direction in the space of a heartbeat, dropping away to nothing or gently ebbing from view. Beyond that, tonight's performance is strikingly minimal, enigmatic, but never austere. Its superheated low-end is matched by a caustic river of fluorescent synth drone - another consistent that's run through most things they've done - but elsewhere the mix is pockmarked only by crisp percussion and looped voices cribbed from R&B and rock. (At one point I swear a microscopic shard of Le Tigre's 'Deceptacon' gets chucked at random into the mix, blindsiding the audience then vanishing.) Many of the more direct references of old - Sade and Cassie covers, Pokemon, YouTube - have been replaced by less recognisable ones, leaving the music feeling more focused in upon itself than ever before. Their drone & bass is still parasitic, but it's less obviously so, absorbing its surroundings by osmosis rather than swallowing them whole. That's matched by the duo's increased vocal presence within the mix. Copeland especially takes command a few times tonight, her thin voice occasionally playing call-and-response with Blunt's smoky raps - towards the end, the pair duet on a sultry version of Black Is Beautiful's low-slung ninth track, a graceful, teasingly brief number.

In this sort of space, near pitch black and so packed that it's impossible to see the performers onstage, the overall effect is reminiscent of being buffeted by dubstep and grime in Plastic People a few years ago. Blunt and Copeland's music isn't so focused on movement, but its actual physical impact is much the same. The songs themselves have become less outwardly abrasive, but this evening's performance is still heavy on dread: rhythms built from gunshots and underpinned by the whine of police sirens, bodies rattled into adrenalised states by heat and bassweight, all contributing to a creeping sense of being undermined. We're jarred; something's not quite right. Even opener 'Trample', a slinky two-step number that's one of their only club-friendly cuts to date, is frequently hacked at with delay and possessed of synth motifs that distend outward into dissonance, subverting Copeland's sugar-sweet vocal delivery.

There's a faintly radioactive glow to proceedings, though. Where dubstep eventually turned the focus inward, sending outer elements running for new pastures, Hype Williams' pop is proving to be a potent mutating agent and a slick assimilator. It's currently sending tendrils out in enough directions to allow it to shapeshift seemingly at will. Its roots, however, still lie in spaces like this - dank back rooms stuffed with people, performers' personalities impossible to glimpse behind the glare of strobe and grotesque rubber masks, allowing the pressure to build almost to bursting point. That's one reason, perhaps, why they are so reluctant to expose its concerns any further to the public's voracious gaze. There's a delicacy to their current state, and the reticent, vaguely sardonic public relations approach that accompanies that sort of existence is what lends them a great deal of their appeal. Tonight that's clearer than ever, despite emerging onto the street afterwards with throats sore from dry ice.