Gyorgy Ligeti baffled his audience with the first performance of `Poeme Symphonique' - a work consisting of 100 metronomes. Bayan Northcott investigates the new meaning of the joker in the pack of modern music.

On 13 September 1963, the good burghers of Hilversum gathered in their concert hall to hear a new commission, reassuringly entitled Poeme Symphonique, by the up-and-coming 40- year-old Hungarian Gyorgy Ligeti, resident, since the 1956 uprising, in Vienna.

So why was the platform occupied not by the expected orchestra, but by 10 assistants standing at tables, each displaying 10 metronomes? More ominous still, why, as he advanced to the podium, did the composer appear to be wearing dress-shirt, trousers and tails several times too large for him? The metronomes were ritually wound up and, on a single downbeat, set going at many different speeds. Whereupon, conductor and assistants solemnly withdrew from the stage, leaving the audience to contemplate the metronomes slowly, oh so slowly, running down.

What could it all mean? Some sort of political protest against official culture? One of those "happenings" the avant-garde had started to go in for since that Dadaistic American, John Cage, with his "chance" methods of music-making, had invaded the Darmstadt Summer School - estwhile hotbed of hardline serialism? Or could anything so outrageous just possibly have serious implications? For, as those could testify who have sat through more recent "performances" - at the Almeida Festival in 1987 or the South Bank in 1989 - the thing does exert a certain fascination.

At first, such is the barrage of beats, one hears an almost continuous torrent of sound, like heavy rain on a tin roof - and, in effect, not so unlike the dense cloud-textures Ligeti had recently been pioneering in such genuinely orchestral scores as Atmospheres (1961). Then, as metronomes start to drop out, slight irregularities, bunchings and holes, begin to appear in the continuum; later still, more clearly audible cross-rhythms, as though one had strayed into some crazy clock shop. And as the remaining mechanisms gradually fall silent - 10, five, three, two - it is difficult to suppress a strange feeling of pathos. Nobody who lasted through the near two-hour Almeida staging will ever forget the tremulous cry of "No!" wrung from someone in the audience as the menacing form of conductor Oliver Knussen re-emerged from the late-night shadows to stop the final tiny ticker.

A surprising number of significant issues can be unpacked from an experience of the Poeme Symphonique: questions about the rituals of concert-giving and the relation of modern composers to their audiences, about determinism and chance in creative method, about illusion and transformation in aural perception, and mechanism and emotion in musical understanding. We are still left in doubt as to whether it amounts to a work, remains an acoustic study, or is just a not-entirely funny joke. But then Ligeti himself maintains: "What I compose is difficult to categorise: it is neither avant-garde nor traditional, neither tonal nor atonal. And in no way post-Modern."

Not that that anything he says is safely to be taken at face value, any more than what he composes. It is interesting, for instance, that he has always insisted his composition students should undertake the strictest training in tonal harmony and traditional counterpoint. Again, his reaction in his works of the 1960s against certain dogma of the Darmstadt avant- garde was so exact as to suggest a continuing, dialectical relationship. Some of his more eclectic scores seem to summon up echoes of the expressionistic atonality of the Schoenberg school, or the folklorism of Bartok, so unmistakably, if distantly, that it is difficult to think of them as anything other than post-Modern. Yet perhaps the ultimate surprise about a musician who seems to locate himself within a labyrinth of conceptual and paradox is the size of his following. Not only has he been a staple figure of new music festivals these 40 years; not only are his complete works down to the last jotting now coming out on disc, but some of his most radical efforts actually seem to be edging their way into the standard repertoire - notably Atmospheres and Lontano (1967), which can quite often be heard opening otherwise conventional symphonic programmes.

Part of the explanation doubtless lies in the complex, often magical sensitivity of what Hans Keller long ago diagnosed as Ligeti's "well-nigh unprecedented" textural ear. In fact, like many subsequent classically- based listeners, Keller recalled that he was initially outraged when he heard the premiere of the earliest of the mass-texture places, Apparitions, in 1960 - clashing fiercely over it with his Hungarian composer friend, Matyas Seiber. "I said there was no form, no structure in the sense of something happening to thematic material; in fact, there was no thematic material. He said, in effect, `so what?'. I said the work was superfluous, a replacement of music. He said: `So what? What is music, nowadays?' and he was right..." Keller came to realise that while Ligeti's static sound- masses might not convey musical meaning in any traditional sense, they were at least free of the numerological hocus-pocus, the socio-political agendas, and all the other "phoney" motivations he deplored in the avant- garde of the day. What Ligeti composed were driftings and layerings of sheer sonority, suggesting a new form of purely textural structure which just might, in time, begin to disclose new musical meanings of its own.

Which, in a sense, is what subsequently happened as the densely inert textures of Apparitions and Atmospheres began to clarify harmonically in Lontano, to break out in multiple accompaniment-like figurations in the Chamber Concerto (1970) and to throw up something like foreground melody in Melodien (1971) - a redefining of the basics of music in Ligeti's own terms which he was to combine with his singular sense of the absurd in his full length "anti-anti-opera" Le Grand Macabre (1974-77).

Having evolved an entire new technique and aesthetic out of his remarkable gift for imaginative hearing, he could then turn, in his works from the Horn Trio "Hommage a Brahms" (1982) onwards, to recapturing aspects of music from the past - no longer, perhaps, as tokens of a living tradition, but at least as haunted objects, so to speak, in some aural Dali dreamscape.

All of which might suggest that Ligeti had followed a kind of masterplan from the start. Yet his own many interviews convey a far more fraught and uncertain view of his development.

Only by a constant interplay of skill and wit, he seems to suggest, can a composer any longer hope to impose order upon, or to wrest something fresh from, a sonorous world in constant danger of lapsing into chaos or running down into entropy. Hence his intensive exploitation, to the point of exhaustion, of technique after technique - chromatic clusters, microtonally corrupted harmonies, teasing Op Art cross-rhythms, and so on and on. Yet if Ligeti really does regard himself as joker in the pack to the fatalistic endgame of Modern music, one wonders what he thinks about the status of old master increasingly thrust upon him. Benjamin Britten remarked of the retrospective junketings that greeted his 50th birthday that they made him feel as though he were already dead. Now in his mid-seventies, Ligeti doubtless realises that the bulk of his output is part of musical history, and that the only way he can exert any further influence over it is to come up with something so new as to alter the entire perspective in which it is heard and judged. Is that why the Alice in Wonderland opera he is supposed to be working on seems so long in coming?

`Ligeti: Clocks and Clouds' continues at the Royal Festival Hall, London SE1 (0171 960 4242) on 11 November; and on Radio 3, 10 and 17 november.

Ligeti is Composer of the Week on Radio 3 from midday next Monday