Jazz Diary: Out from behind the score - Classical musicians learn how to make it up as they go along - Andy Gill's round-up of new albums

Making it up as you go along is second nature for jazz musicians. But for many classical performers, improvisation is not just difficult, it's physically painful. Being asked to leave the dots of the score behind is apparently the cause of much nervous tension among otherwise well-adjusted musicians.

This wasn't always the case, as Derek Bailey's recent series for Channel 4, On the Edge, pointed out; Bach, Beethoven and Mozart were expert improvisers, rocking out cadenzas at the drop of a hat. But some time in the 19th century, the convention of improvising disappeared from classical music. For most of the last hundred years the domination of written notation over 'serious' music - outside non-Western traditions, jazz and the odd piece of avant-garde indeterminacy - has been complete.

Despite the discomfort and insecurity it can cause, some classical musicans actively seek out opportunities to breach the pain barrier. The Romanian-born violinist Alex Balanescu - who appears with Carla Bley and the Stewart Forbes Big Band next week as part of the Glasgow Jazz Festival - has found his relatively recent involvement in improvised music a liberating experience. Balanescu trained at the Juilliard School in New York, but found it too restricting, 'like a factory for turning out string players who play in a particular way.'

He reacted by seeking out contemporary composers like Glenn Branca, whose methods were less rigid. 'Classical music people use their scores to hide behind. In order to become expressive you have to forget your training, which is always loyal to notation,' Balanescu says. 'Through improvisation you can learn a lot about textures, about rhythm and about different kinds of role for the player.'

Balanescu is nothing if not eclectic. Future projects include an album of tunes by Kraftwerk and David Byrne (out in September on Mute Records) and an appearance at the Seville Expo with the Lounge Lizards' John Lurie. He has no regrets about the direction his music has taken. Perhaps he could have been lead violin with the Chicago Symphony; but 'that would be boring,' he says.

While improvisation may put iron in the soul of musicians, it doesn't always put bums on seats. There was an understandable air of trepidation attending last Friday's opening of a new club dedicated to free jazz, traditional folk and contemporary classical music.

The Rare Music Club, in Bristol, has been set up by the pianist Keith Tippett as a forum for the kind of music he likes to play and listen to, in an informal nightclub setting. The problems of drawing a crowd with music that has almost been expressly designed not to do so, were compounded by difficulties over the location: the Malaap Club, an Indian bar and restaurant in one of the city's crustier streets, is not the usual environment for fans of any of the opening attractions - the Balanescu String Quartet, the Irish piper Steafan Hannigan or Tippett's co-operative quartet Mujician. 'The idea for the Rare Music Club stems from the heart,' Tippett said on Friday. 'Let's face it, it certainly didn't come from the brain.'

At one point, it looked possible that the musicians themselves would fail to arrive: half of the Balanescu String Quartet sat eating a curry and watching the European Championship Final on television while the other half were stuck on the M4. Even Tippett's own quartet had become a trio, with the bassist, Paul Rogers, missing since the election, and now believed to be living in France. But at last the musicians and a crowd of a hundred or so made the gig. Artistically, the evening was a resounding success. The Balanescus played Michael Nyman string quartets while the turbanned owner of the Malaap, Mr Sandhu, pulled pints at the bar, and the evening ended with Hannigan joining Mujician for a Celtic- fringed free improvisation.

The club will continue for as long as it can command an audience. This Friday Mujician are joined by the classical clarinettist Ian Stuart and future attractions include the pianist Julian Jacobson, the Composers' Ensemble with Mary Wiegold, and the first ever solo performance by Julie Tippett, the former soul belter Julie Driscoll.

The Rare Music Club is at the Malaap Club, 140 Cheltenham Road, Bristol. Further details on 0272 351536.

Improvising freely does not present a problem for the classical pianist Katia Labeque, but the relatively basic jazz skill of accompanying a solo does. Labeque has just completed a British tour with her partner, the guitarist John McLaughlin and his trio, in which she performed both solo and as accompanist.

'Improvising the chords behind John's solos is for me very difficult', she says. 'It would be nothing for any normal jazz pianist, but jazz is not my world, and John can improvise on many different chords in even one bar.'

Like Balanescu, Labeque experienced problems in her training (at the Paris Conservatoire), but these were related less to music than deportment - she sways as she plays. When she performs as a duo with her sister Marielle, Katia moves at the keyboard as if her body is possessed by the music, while Marielle remains perfectly poised. 'It's a natural thing - the emotion in the music provokes the gestures - but it was very much criticised at the Conservatoire.'

McLaughlin has been fusing jazz with classical sources from both Western and Eastern traditions for years, but he has never learned to love the classical guitar. 'It's not visceral enough for me,' he says. 'I'd rather listen to a blues or a flamenco player. I miss the rhythm in the classical guitar repertoire.'

Despite his reputation as the guitar-hero's guitar-hero, McLaughlin still keeps up to date with the opposition, even putting in a good word for Eddie Van Halen. He was once quoted as saying he always wanted to know when there was a good new guitarist around so he could send someone round to break his hands. 'Yes, it's true,' he says, 'I hate them all]'

The Jazz Festival season begins in earnest this month. Glasgow (2-11 July; telephone 041-227 5511 for information) is the most star-studded, with the McCoy Tyner Big Band, Elvin Jones, Herbie Hancock, the Count Basie Orchestra, musician-in-residence Carla Bley, Grover Washington and many more. It's also the venue for the debut, on 3 July, of a remarkable new quintet formed by the brilliant South African pianist Bheki Mseleku, with Steve Williamson and Eddie Parker joining the American rhythm section of Marvin 'Smitty' Smith and Charnett Moffett. The group also plays London's Jazz Cafe (4 July) and Old Bull Arts Centre (5 July).

(Photograph omitted)