Using a computer, he cleaned the orchestration and harmonically opened the piece up. When asked to explain, he chooses his words carefully and, since I only half understood them, I'll give them here verbatim. "I created an artificial overtone series beneath the chords I used in the original version," he said. "The computer made it possible for me to reinterpret my original harmony, and it found a virtual fundament to each chord I had used in 1981 without taking any account of natural harmonies." This sounds, I suggest, very like Roger Scruton's theory that the atonal works of Schoenberg can be reinterpreted tonally. "Well," says Salonen, "it did teach me something. My original harmonies were not particularly dissonant, but they were intentionally chromatic."
So how does the new version differ? "It's lusher and fuller. It uses the full sonority of a small orchestra. My music these days is much more visceral than it used to be." A concession to the demand for accessibility? "We all change. In my early twenties I was in the middle of a strict modernist training, and my gods were Boulez, Berio, Stockhausen, and Ligeti, and though I still admire those composers, my emphasis has changed." To what? "Let's say it's moved from Schoenberg to Stravinsky. I now see the dodecaphonic period as interesting and fruitful - it led the the creation of some absolute masterpieces - but it came to a dead end. Chromatic music has given way to modal.
Does he agree that the austere esotericism of 12-note music was responsible for driving away classical audiences? "No, that's an over-simplification. There were many reasons for that. I realised one recently when I was reading a cultural history of St Petersburg. When Tchaikovsky died, schools were closed and thousands thronged the streets for his funeral - the sort of response which is now accorded to someone like Elvis Presley.
"No, the real reason for the drop in audiences lies in the marginalisation of high art by the media, and by its exaltation of the role of the interpreter at the expense of the creator. I know this from personal experience, since I wear both hats. There's a tremendous industry behind every successful performer, which completely overwhelms the feeble efforts of the music publishers on behalf of their composers."
But he's concerned not to overplay this hand: a lot of "totally worthless" music was written in the Fifties and Sixties, and was not nipped in the bud. "There was a very effective little mafia at work, thanks to the American-financed German post-war radio network. That was composed of great supporters of modernist music, with fine orchestras and endless rehearsal time.
"At the same time, there was very little enlightened criticism. Everything conspired to convince the public that new music sounded like shit - and it quite often did! I still listen to the best music of that period - but I would never again want to listen to Stockhausen's Klavierstuck No 1. That's one of many pieces which are now utterly dated."
Then he adds, with a laugh, that history is littered with ludicrous failures to sift gold from dross, and points a Finnish moral. When Sibelius went to study in Vienna his tutor was Karoly Goldmark, who at that time was widely regarded as Beethoven's natural successor. "But who listens to his music today?"
Salonen may live in Los Angeles, but he spends two months of each year at his summer house near Helsinki: he's still close to his roots. For him Finland's musical pre-eminence is a matter of pride. As he points out, music's importance there is a direct result of the country's political history. So long as Finland was under Russian control, it was linguistically divided, with the middle classes speaking Swedish and the lower classes Finnish; music was the only art able of evade the Tsarist censorship and uniting the nation.
Thoughts like these engage him deeply, but his current preoccupation is the song-cycle which he's writing for Dawn Upshaw plus chamber orchestra. He has constructed his own libretto from the extant fragments of Sappho's poetry, and is composing a five-episode work taking its female protagonist from birth to marriage; he has enough material left, he says, for a further cycle covering the second half of life.
After this, he will plunge into uncharted waters: he's taking next year off from conducting in order to write an opera. What's it about? He will only say that Peter Sellars will direct. But its commission was auspicious. "I was doing a new production of Rake's Progress with Peter Sellars at the Chatelet, and after one inspiring day I told my wife how much I would like to write an opera of my own. Next day Stephane Lissner - who now runs the Aix-en-Provence festival - asked me, out of the blue, if I had ever considered embarking on an opera. I don't believe in signs, but as a coincidence this seemed remarkable." Work starts when his conducting stops, in January 2000. He's both curious and a little nervous about what it may hold.
Esa-Pekka Salonen's `Giro' will be performed at the Last Night of the Proms on Saturday. This article first appeared in `Full Score'