Chaka Khan, Ronnie Scott's

The voice is the pinnacle of instruments, the surefire road to the heart. But the core humanity which distinguishes it can work both ways: the vulnerability displayed so powerfully in human song makes possible the expression of powerful emotions but it can also pitilessly expose the flaws in an artist’s work.

Chaka Khan is without question one of the great voices of R&B and disco: a belter who could also be soft and tender, a party animal who drove people onto the dance floor for several glorious decades. The audience at Ronnie Scott’s for the last in a series of sold-out performances were more than happy to see their idol in such an intimate and hallowed space. The fire was evidently still there, even if she had to make a joke of not remembering song titles, making light of her bumbling ways.

It became evident,however, as she started a run of classic hits, that she no longer had control of pitch, and while she managed plenty of phrases, there were embarrassing moments when the pitch lazily fell off and she had to struggle back to recover the right intonation. She was well-served by a note-perfect and superbly timed trio of backing vocalists, and a tight band who drove the show with great energy. The noise thankfully covered the star’s vocal difficulties, but not always, and listening to her induced a kind of panic, as she teetered between instants of brilliance and cringe-making flatness.

She is fully there for the fans, and the show must go on, even if it is a little out of tune

The most inspirational African-American singing, whether it is in blues, gospel, jazz or soul, is characterized by melisma, a spine-chilling play with the relationships between tones and the semi-tones between them. This requires a paradoxical mixture of improvisational surrender and total control. The best make it sound easy, but it’s a high-wire thing, and very easy to fall off the edge.  Sadly, for all her vocal energy and contagious good humour, Chaka Khan no longer has the means to walk that difficult line.

There were times when it seemed that she had found her balance, as when she sang the ballad “Angel”: she was both touching and strong, in fine voice at last. And yet, with “Sweet Thing” that followed, she was once again flailing about, barely masked by the support of her singers, whose perfection tended to highlight her own deficiencies. She went out into the audience, capitalising on the their unquestioning (and in the circumstances probably tone-deaf) adoration, singing to individual men and women, looking into their eyes and bringing to the venerable jazz club something of the old time gospel revival meeting, the spirit rising, as an increasing number of people got up to dance.

There is something immensely endearing about Chaka Khan: she doesn’t play diva tricks or come across high and mighty. She is fully there for the fans, and the show must go on, even if it is a little out of tune. She can still bump and grind like the best of them, as groovy a senior pro as they come.

She went off for a rest and the band played a couple of tight instrumentals: the guitarist fancied himself a little too much – as they do – but had flawless technique. There was the mandatory, but very good, drum solo, and an even better display of virtuosity tempered with real musicianship and invention from the man with the wide-ranging seven-string bass.

When she returned, presumably rested, she struggled through “My Funny Valentine”, a tall order in the circumstances, and then launched into a string of old favourites “Tell Me Something Good”, ”I’m Every Woman” and “Ain’t Nobody”.  She once again plunged into the audience, surrounded by hefty bodyguards. She set about charming the punters – all of them in pig heaven – lapping up every chance to have the star saucily tweak a cheek or offer a brief hug. The lead was taken by the tallest of the backing singers creating the illusion that Khan was still belting. Ronnie Scott’s was ablaze with the power of funk, and Chaka Khan’s distinctly greying generation, ready to party all night long, were more than satisfied.