Given that The xx made their rise to mainstream acceptance through music that spoke of the terror of intimacy, and secrets whispered between confidantes, lovers and friends, it's perhaps unsurprising that their series of three small London dates for Eat Your Own Ears are low-key affairs. There's talk that no press were permitted to any of the events - in which case, full disclosure, the Quietus paid for entry because, y'know, we've very much been long-term fans of this most curious of English pop groups.

Fans applied to a lottery for tickets to the three gigs (the first was Monday 14th at Islington Electrowerkz, the final date taking place on Friday 18th at Battersea Arts Centre), with this middle date taking place at a seldom-used converted chapel in Homerton, one of East London's few remaining rather sketchy areas. It's a rapt, strikingly young audience tonight, who greet tracks new and old with voluminous, and deserved, applause. Then again, The xx (their black outfits judiciously set off with silver jewellery) hardly seem to have aged a day in the long while since their last show.

"We played our first show in two years yesterday and a lot went wrong," says Oliver Sim. "Bear with us if it does... and thank you for being here." He needn't have worried. For tonight the mixture of reworkings of older songs (which the Quietus last heard at their excellent performance at Matt Groening's 2010 All Tomorrow's Parties) and new material suggests that The xx's sparse blueprint is far from tired.

Lyrically the new songs suggest a continuing untying of the fragility of the knots that bind together human to human, whether as lover or inseparable friend. "With words unspoken / silent devotion / being in love with you as I am" runs one; "Wake up alone / the daylight between us… fiction when we're not together", another. In that track, sparse guitar interplays with electronic drums, creating something akin to Talk Talk playing a gig to a lonely penguin atop an iceberg, lost in the Arctic. Needless to say, that is a very good thing. As well as Sim and Romy Madley Croft's bass, guitar and double vocals, the breadth and expansion of sound comes from Jamie XX, who seems to have gear spread across the width of the stage - floor tom and snare as well as electronic drumpads, MPCs and other hidden devices.

These are used to terrific effect on another new track, possibly the longest, most complexly arranged XX song yet. It introduces steel drums used as a kind of fluid background melody instead of rhythm. The latter is instead provided by an excellent Burial-esque piston-clop, that has a strange breakdown before a vocal melody returns over the top. Given that sonically it's essentially a singer-songwriter duo playing in a venue above a well-appointed nightclub, sounds meeting in the beams between, it shouldn't work. It's a testament to skill of The xx as balancers of melody, emotion, sound and rhythm that it does. Like the electronic music that inspired them and the city which gives The xx their character and detached definition (they're probably the most 'London' band of recent years) this is entirely immersive, like those black uniforms merely part of the armoury that to create this special world.

Of the older material, 'Crystalised' has reverb on guitar, aurora borealis abstract electronics that reflect the oily projections, a synth line that comes and goes like a gull caught in the night lights of a trawler. What you'll never get off The xx from those endless TV idents and clearly lucrative publishing syncs is the bass which, in 'Crystalised', is deployed in huge lumps. This is in part what keeps The xx fresh, what has stopped their ubiquity from hampering them. The same goes for 'Intro', which as Jude Rogers reminds me was the theme song for the BBC's coverage of the 2010 General Election. That a track that accompanied this bastard government sniveling and sneaking into power hasn't been ruined by that says something, especially tonight with a brilliant quiet white roll of a bassline, ice-tear OMD synth and key down a well echo. First date sees their palette expanded further, three or four elements (Tube running some way beneath rumble, detonation bass, croon) bouncing in and out of each other as if elasticated.

From the textures and beats deployed in the new material played tonight, it seems that The xx's second record might well prove a valiant effort to reclaim what one might be forced to call 'post-dubstep pop' away from yumping numpties like Skrillex. You imagine there must, surely - after a meteoric rise, endless touring, the pressure, the second album thing, Jamie XX seemingly turning up to DJ anything from nightclubs and festivals to the openings of village fetes - be some kind of tension. If so, it's immaculately hidden behind this elegant performance and new material. As Oliver Sim, a person - like the rest of the group - of few words, remarks, "it's a fun time at the moment." It is this audience's quiet pleasure to be along.