Over the past 20-odd years of R&B we've become used to the idea of female R&B stars being lubricious Amazonian ululators. So when someone a little different turns up, such as the high-necked, Metropolis-obsessed Janelle Monae, say, or even the bloody-minded playground taunter MIA, it can feel, on the one hand, like a category failure or, on the other, like an unexpected gulp of oxygen in an overheated basement club.
The reason that female R&B is so locked into one phenotype is in no small part down to Beyoncé Knowles, occasional leader of Destiny's Child and undisputed grande dame of the genre you might just call R&Bey and be done with it. A Madonna-style fly-on-the-wall documentary on the elder Knowles is expected next month.
Coming at R&B from a very different set of co-ordinates is Solange – the Knowles sister in the know, if you like, or "the indie Beyoncé", for those with less lateral movement. In recent years Solange has reinvented herself from Destiny's Child spare part (standing in, age 14, when Kelly Rowland broke her toes), to cult figure, to something of an alternative icon in embryo. The first real signs of Solange's new modus operandi were telegraphed in 2010 when she covered a Dirty Projectors song, Stillness Is the Move, translating its art-school, Afro-inflected R&B back into actual R&B.
Dressed tonight in a magnificent fashion-forward suit whose baroque patterns and vivid colours would send your TV picture crazy, Solange leads her band in the kind of formation dancing not seen since the R&B road shows of the 60s. Her first London gig in four years is the kind of show where half of London appears to be crammed into a hot basement, while the other half of London is outside tweeting plaintively that they will do anything to get in.
From my vantage point near the men's lavatories it's sometimes hard to hear Solange's aerated vocals over the constant whirr of the Dyson hand drier. But her take on R&B – one refracted through art-pop, the 80s and back again – is far fresher than the smell of the deodoriser tablets they put in the urinals.
These are intelligent songs about love going wrong, glossed with heavenly coos and backing harmonies and given percolation by the band's gentle funk. By the standards of commercial, bootylicious R&B they feel lightweight. But that is no criticism. Some Things Never Seem to Fucking Work has the innocent swing of the 60s, the blithe synths of the 80s and a breeziness that belies the f-word of the title.
A collage of percussive tishes laid over with Solange's feathery croon, Lovers in the Parking Lot unfurls like a forgotten early-90s R&B cut. Solange herself is both elegant and down to earth, her amber Texan speaking voice contrasting with her more ethereal singing voice. Somehow she looks younger now than she did when she was releasing anonymous, commercial cuts such as Feeling You in 2002.
Apart from actual ghosts such as T.O.N.Y. (from her second album, 2008's Sol-Angel and the Hadley St Dreams) and Crush, a Pharrell Williams production that survives intact from her first album, 2002's Solo Star, much of tonight's hour-long set is culled from True, Solange's most recent EP, released last November. It was recorded alongside Devonté Hynes (Blood Orange, Lightspeed Champion), a former fixture in east London gigging circles, almost unrecognisable on guitar tonight.
True came out on a micro-indie called Terrible Records, run by Chris Taylor of the digressive Brooklyn art-rock band Grizzly Bear, an outfit Solange has dragged Beyoncé and Jay-Z out to see. A full-length album is imminent.
It all ends tonight with Losing You – the extraordinary single – and the sunny, retro joys of Sandcastle Disco. Solange is 26 but has been working in the industry since her mid-teens. As well as releasing two albums she's been married, lived in Idaho, had a son and divorced. Perhaps the comparisons with her sister can end now, not least because her effervescent songs defy the apologetic qualifiers "indie", "art" and "cult".
