International Jazz Festival, Cheltenham

Flying by the seat of his pants: the guru with the flute and the donkey

Hermeto Pascoal is a short, stubby Brazilian whose long white hair and beard make him look like Robert Crumb's famous comic-book character, Mr Natural. The 67-year-old composer and multi-instrumentalist - you name it and he plays it, whether it's a musical instrument or not - is also the nearest thing to a shaman-figure that jazz has left. The trouble with shamanism, of course, is that it's a bit like homeopathy: you're never sure if it works.

Hermeto Pascoal is a short, stubby Brazilian whose long white hair and beard make him look like Robert Crumb's famous comic-book character, Mr Natural. The 67-year-old composer and multi-instrumentalist - you name it and he plays it, whether it's a musical instrument or not - is also the nearest thing to a shaman-figure that jazz has left. The trouble with shamanism, of course, is that it's a bit like homeopathy: you're never sure if it works.

Appearing at the Everyman Theatre with a specially formed big band made up of British players plus three compatriots he'd flown in with from Brazil, Pascoal presented us with an enigma from the start, for what he brings to his role as a bandleader isn't anything so mundane as tunes or arrangements, although he has plenty of both. It's more a sort of non-specific essence, an arbitrary sprinkling of magic fairy-dust here and there so that the overall musical experience is somehow transformed or heightened. Certainly, this is a difficult art to get right and Pascoal treads a treacherously narrow line between being, say, a genius and being not much use at all. He also plays the flute, which is another problem.

The British musicians, some of whom had worked with Pascoal before, clearly revere him, although you can't help feeling that this may be due to his sheer brassneck audacity; a willingness to fly by the seat of his pants that leaves even the most seasoned of improvisers shaking their heads. As Pascoal speaks no English, his aide-de-camp, the pianist Jovino Santos Neto, would explain the background to each piece - that it was inspired by a calf in a field, for example, or a donkey - while Pascoal nodded gnomically in the wings. Then they were off.

Or rather they weren't. For a big band, the ensemble passages and solos came relatively infrequently, with everything left to Pascoal's whim as the musicians, who had hardly got going, would then stop to let him play a bit of flute, or accordion, or keyboard, or the old kettle that lay on a table full of instruments in front of him. At times, as when he produced a variant of north-eastern folk music on the accordion, the effect was stunning; at other times it seemed more like aimless noodling.

What gradually became clear, however, is that what you get out of a Pascoal performance is directly related to what you put into it. If you're prepared to put aside your doubts and believe, then Pascoal really can seem like a genius. As the band grew in confidence and each cog in the whole mad machine started to mesh together, there were some marvellous moments. Chris Biscoe played a baritone sax solo of astonishing fluency, poised precariously like a surfer on his board as the huge wave of the band's oncoming chorus rushed towards him from behind. At the end, Pascoal did a party-piece whereby he'd sing a brief phrase that the audience would then attempt to echo. It's an old game but a good one and as we all struggled to match the increasingly obscure chants, the good vibes in the house grew more beneficent still. You left the theatre feeling full of love.

"This isn't a good sign," said Cassandra Wilson to her band a third of the way through the Festival's closing concert on Monday night. She was trying to get the audience to clap along, and meeting unexpected consumer resistance. Maybe as punishment, she gave us a little lecture on the importance of rhythm in the introduction to the next song. "It's good for this," she said, patting her behind, "and this," pointing to her breasts. Well, Cheltenham (or Chelt'nam, as she accurately pronounced it) tried to get funky, but failed. To be fair (and Wilson, who looked foxy in blonde dreads and a red sun dress, wasn't at all stroppy about it), it's hard to feel the rhythm when you're stuck in a folding metal chair in a joyless mausoleum of a building (the Town Hall) that even John Betjeman, one feels, would have a hard time liking.

But the Town Hall did manage to shake it for Gilles Peterson and Amp Fiddler, two thirds (with the band of veteran Brit-jazz trumpeter Harry Beckett) of an odd but very enjoyable triple-bill in the Saturday night slot. After Beckett and Co (with saxophonist Chris Biscoe again) had battled against the cavernous acoustic, and Peterson had played some killer tunes, Joseph "Amp" Fiddler from Detroit stole the show with a wonderfully animated performance of flower-power jazzy-soul. Dressed to impress in a curiously formal outfit whose jacket he soon discarded to reveal a neat psychedelic vest, Fiddler sang, danced, rapped, played keyboards, led his five-piece band, and looked cool. At midnight at Cheltenham Town Hall, that's more than enough, believe me.