Fireworks in progress

Composers and theatre directors are supposed to seek precision in their work, so that we hear and see what they intend us to hear and see. It's disconcerting, then, to hear the German composer and director Heiner Goebbels extolling the virtues of vagueness. "Vagueness is precisely what interests me, what keeps me awake in the theatre," he says, "I really like it if things are not too settled, too secure, too established, but rather shifting from one category to another in terms of theatrical elements."

Composers and theatre directors are supposed to seek precision in their work, so that we hear and see what they intend us to hear and see. It's disconcerting, then, to hear the German composer and director Heiner Goebbels extolling the virtues of vagueness. "Vagueness is precisely what interests me, what keeps me awake in the theatre," he says, "I really like it if things are not too settled, too secure, too established, but rather shifting from one category to another in terms of theatrical elements."

That fluidity has been a hallmark of Goebbels' career, notably in his theatre work and particularly his show Max Black, which opens in London this Thursday. It is a theatre piece with music and Goebbels is both director and composer. Its genesis is linked to Goebbels' beloved vagueness: "I came across a book on logic which quoted an article called 'On Vagueness' written in the Thirties by a certain Max Black, a Russian-American scientist. Without understanding it at all, I loved the subject, and I loved the name. I began researching other writers who had written on vagueness - Wittgenstein, Paul Valery, Lichtenberg. Out of their work I compiled a fictitious monologue for a character named Max Black, because I found the name so attractive."

Whether written for the concert-hall, the theatre or the radio, Goebbels' work has never been predictable. Take Black on White, seen in Edinburgh in 1997 and in London last July, a piece of music like any symphony, but neither sounding nor looking like any orchestral concert you've ever seen. The musicians (from the Frankfurt-based Ensemble Modern) were required to play skittles, throw tennis balls at an amplified thunder-sheet, boil a kettle of water to the accompaniment of a piccolo as well as some conventional playing - al though Goebbels' instrumental music, straddling classical composition and avant-garde jazz, is anything but conventional.

Black on White bears the credit "Conceived, directed and composed by Heiner Goebbels" but that barely suggests the collaborative procedures behind his theatre works. He is more like a choreographer working with and through dancers. "At the first rehearsal for Black on White, I had no score, not a note written. I looked at the players of Ensemble Modern, how they held their instruments as they improvised, taking in what the individuals offered in different registers, on different instruments. The Japanese percussionist said 'I have a Japanese koto at home' so I said, 'bring that along,' and the koto ended up playing a big part. I didn't want a grand piano onstage, so I asked the pianist if he had a smaller instrument that might be portable. He said: 'Of course. I have a clavichord.' That changed the piece again. You could say that I compose like a theatre director, who looks at their actors and sees certain abilities, characteristics, possibilities to develop."

Which brings us back to Max Black. Goebbels describes it as "a kind of revenge on Black on White. There the musicians were the actors. Here the actor makes the music." The actor is André Wilms, with whom Goebbels has often worked. "André has a wonderfully rich voice," says Goebbels, "but that is not what first attracted me to work with him. We developed a very easy collaboration of a kind that is rare. Conventional actors are always asking 'Why?' 'Why should I walk from this side to this? Why should I say this here? What do I feel when I say this?' I can't answer their questions, and it doesn't interest me to fake the answers. I'd rather work with an actor who can collaborate like a musician. Musicians never ask, 'Why do I play an F sharp here!' I have the feeling that the more restrictive I am, the livelier André is."

That may sound autocratic, but the process is two-way, he says. "Some directors demand a kind of hysterical quietness in their rehearsals. Nobody is allowed to breathe, nobody is allowed to move out of place. When I work, everybody can breathe, everybody can move. While the actor is trying out a certain text, someone might come on stage and give him a different hat, or a pair of glasses, and the sound engineer might be processing his voice so no one can understand him anymore. It's like a chain reaction of theatrical elements, a sequence of experiments: which is just what the character Max Black is up to."

In the case of Max Black, those experiments demand a pyrotechnician, about whose contribution Goebbels is suitably vague. He doesn't want to pre-empt any coups de théâtre. He does, however, reveal what kind of music we can expect: "André Wilms' musicality is immense, even though he hasn't been trained to play any instrument, but I didn't work from a preconceived musical starting point. The ideas developed from the sounds it was possible to create with, and from, André and the objects we had onstage. Whatever he touches, whether an old bicycle or a laboratory beaker or his costume, creates a sound which is turned into music. Instead of training André to play the cello, I discovered how beautifully he could play the spokes of a bicycle."

If Goebbels didn't have a genuinely musical sense of theatre and a genuinely theatrical sense of music, he might be just one more artist allowing the creative process to take precedence over product. In this country the words "music theatre" conjure up faded Seventies experimentalism. At 47, Goebbels has absorbed what those experiments achieved but acknowledges the need to move on. He has duly injected new life into the form.

In more ways than one, audiences for Max Black should expect plenty of fireworks.

'Max Black' at the Lyric Hammersmith, King St, London W6 (0181-741 2311), 7.30pm Thurs to Sat this week. A recording of 'Black on White' is available on BMG