As the musicians strike up their version of Neil Young's "Harvest Moon", familiar from the wonderful new album New Moon Daughter, it's clear that something is wrong. The sound balance is terrible, the acoustic instruments that it should be as easy as pie to mix are a muddy mess. And the star? Well, at best, she's abstracted; at worst, she's somewhere else entirely. We shuffle uneasily in our seats, trying to enjoy it. And, eventually, it all starts to come right, the focus of the music sharpening to a needle point, the nostalgic whine of a National Steel guitar pricking at the heart, as Wilson throws her head back to laugh delightedly, and brushes the hair from her face. But it's now half past 10 and people are starting to leave for their transport home and their babysitters...
The promoters didn't know about the support act. Wilson, it seems, is as much an enigma to them as to anyone else. When I ask for details of the band for her show at Shepherd's Bush Empire on Monday night, they don't know that either; all that is certain is that a lot of hotel rooms have been requested. They are also in the dark about an event I have received a fax about, when, on Tuesday at 5pm, Wilson is evidently due to appear at London University's School of African and Oriental Studies in a workshop for the Yoruba Contemporary Arts Trust. As someone says, all Cassandra Wilson needs to do to further her already brilliant career, is to turn up and look as if she is enjoying herself. But sometimes it seems that even this might be too much for her.
Conversely, it's all too easy to forgive her anything. After all, many great reggae singers seldom bother to turn up at all, and Wilson's two Blue Note albums, Blue Light Til Dawn and New Moon Daughter, are astonishingly good, extending the range of contemporary vocal jazz to include pop, folk and blues songs, without compromising the fierce integrity of their overall concept. In a good performance, such as that at Birmingham's Ronnie Scott's three years ago, Wilson is capable of sounding like the best singer you've ever heard, and her accompanists - a post-modern version of a Memphis jug-band - can seem like the most polished and tasteful group in the world. An important extra is that Wilson also looks the part: a mature, sultry beauty with a Billie Holiday gardenia in her distressed, dreadlocked hair, who commands at least as much erotic attention from women as from men. She also moves sensually as she sings, each gesture alive to the nuances of the backing musicians; and her smoky, wistful voice, crucially, sounds natural and unforced, forming an essential counterpart to the band's environmentally- friendly, acoustic rusticity. In short, she's great, but, again like Billie Holiday, she doesn't do herself any favours. Despite the confidence and the poise, she can sometimes seem uncomfortably close to the edge.
In conversation, she's hyper-intelligent, and alert to all the vagaries of the female jazz singer's role. "You can't just be a drug addict and create music like that," she says of Holiday. "There has to be a certain amount of discipline. There's always the assumption that these people came to music very naturally and coincidentally, but I don't believe that. It takes far too much work. With jazz singers especially, there's a particular stereotype at work. They're not looked upon as being innovative, they're just kind of background figures in the history of jazz, and I've always been the kind of person who rebels against that stereotype..."
Now a late-30-something (her fulsome press cuttings always neglect to mention her age), she was born in Jackson, Mississippi, to a musician father (the guitarist and bassist Herman Foulkes), and learnt piano before taking up the guitar and performing as a folk singer in clubs. Moving to New Orleans to study broadcasting, she married for the first time (she now has a young daughter), and began to sit in with some of the city's close community of jazz musicians, including Ellis Marsalis, Wynton's dad. Re-locating to New York, she fell in with the Brooklyn M-Base collective led by saxophonist Steve Coleman, with whom she recorded. A contract with the German label JMT led to eight albums of mainly strident M-Base funk (the collective sought to reclaim jazz for a black audience by incorporating the rhythms of hip-hop, not always successfully), as well as the stunning standards set, Blue Skies (1988). This attracted a considerable following due to the distinctive, wide-open spaces with which she invested the often claustrophobic atmosphere of the classic jazz-vocal tradition. Truly, a good jazz singer is hard to find.
Her big success, however, had to wait until 1993 and the release of her first album for Blue Note, the astonishing Blue Light Til Dawn. The repertoire returned to her early folk roots, mixing jazz standards with blues by her fellow Mississippian Robert Johnson, and singer-songwriter classics like Van Morrison's "Tupelo Honey" and Joni Mitchell's "Black Crow". Produced by Craig Street, a jobbing builder she had met in the lobby of her Harlem apartment-house, the album was remarkable - at least for jazz - for its resolute determination to convey an overall ambience, a mood whose governing melancholy and spare, acoustic instrumentation counted for more than its constituent parts. It was still jazz, with cameo performances by some of the most adventurous players on the New York scene, like reeds player Don Byron, but it was also bedsit music par excellence. "Tupelo Honey" in particular is the kind of song that you can play as if it were Leonard Cohen, repeating it over and over again as the consoling accompaniment to a solipsistic depression.
This year's follow-up, New Moon Daughter, is more of the same, but even better. The catholicity of taste has been extended to take in covers by such unlikely figures as Hank Williams, U2 and the Monkees ("Last Train to Clarkesville", a song she says she has wanted to do for years). It also showcases her own original compositions which have now grown to become wholly impressive, fully-formed songs, whereas previously they lacked the resonant power of the cover-versions. Typically, the material deals with sex, darkness and obsessive love, even the "little death" of orgasm. "It's about the mood of life," she says. "Wherever it carries you. The album goes deeper into my folk roots, an aspect of my musical personality that hasn't really been explored. Playing the guitar again has brought about a great change in the way I'm perceiving my music; it's now far more immediate and uninhibited, a radical change to the approach I used to have."
She says that she can empathise most with songs of obsessive love, like the standard "Body and Soul", which she has sung for years. "The way that you empower yourself is sometimes to rewrite the words, to change the way you look at a song in order to step outside of the victim persona, but I think the lyrics of `Body and Soul' are about submission, and that's something I can identify with. It's a kind of falling back into darkness, like boom! I'm in love, and that's a real human emotion."
As a jazz vocalist, Wilson avoids the rather cliched heritage of scat- singing, though she still occasionally sings without words. "I prefer to look at it as improvisation," she says. "You move with the music and you move with the moment. It's a kind of spiritual liberation when you sing; it's also once again about submission, and of allowing whatever's going to happen, to happen, a relinquishing of the ego. Sometimes you just have to get that out of your personality so that you can become a vessel or whatever. Music is ritual. The voice is the first instrument and everything is a derivative of that."
New Moon Daughter will certainly reckon in any list of the year's best albums, and at Shepherd's Bush Empire on Monday night, expectations will run high. The danger in becoming the new Billie Holiday, however, is that people begin to expect Billie's habitual personality-disorders as well as her moth-in-a-flame intensity, and for Cassandra Wilson this could become a burden that is too hard to bear. Let's hope that there's a change of support act, at least.
Cassandra Wilson plays on Monday night at Shepherd's Bush Empire. Booking: 0181-740 7474