Edinburgh Festival: Music: Putting on a brave Front Not enough time, alas, for this 'Child' MUSIC

Having reached an age to lie about when anybody asks, I can understand why Edinburgh - that supposed celebration of all things youthful, bright and vigorous - isn't making too much of the fact that this is its 50th anniversary year. Some festivals would write it in the sky, with canon effects. Edinburgh is making do with quiet nostalgia afternoons at Queen's Hall where the not-so-young gather discreetly to hear tapes of festival performances long past, and the odd, live, walk down memory lane provided, for example, by the all-Tippett concert at Usher Hall on Monday.

Richard Armstrong took the Scottish National Orchestra briskly through Tippett's Corelli Fantasia and Concerto for Orchestra which were both Edinburgh commissions and had their premieres in this same hall in 1953 and 1963 respectively. From the surviving photos, it looks as though they pulled a bigger audience then; and it's a mark of how the Festival has grown too monstrous for its own good - with too much in competition for the same night's punters - that even the inclusion of A Child of our Time on Monday's programme proved conspicuously resistable to the festive throng. If you can't sell easy-listening like that at Edinburgh, what can you sell?

The modest turnout was a pity, because it was good to hear these pieces on home ground; and while Armstrong's attempts to firm up the frantic counterpoint of the Fantasia produced a string sound more strident than luscious, the Child was an impressive piece of work with startlingly well- regimented discipline from the Edinburgh Festival Chorus. The spirituals could have been allowed more space, more heart, and it wasn't such a good idea to place the soloists behind the orchestra where they tended to disappear into heavy textures. But they were effective soloists with clean diction and distinctive personalities: Christine Brewer, Ian Bostridge, Alastair Miles and the ravishing Canadian mezzo Michelle DeYoung.

They didn't stop me feeling, as I always do, that A Child of our Time is a magnificent vehicle for bogus arguments (reconciling light with darkness isn't much of an answer to Auschwitz), but they did affirm the broadly humanitarian intentions of the piece with a conviction that discounted logic. An essential requirement in Tippett.

An essential requirement in performances of Pierre Boulez (laid down in performances by Pierre Boulez) used to be a chillingly straight-laced sobriety; and I can remember readings of his work-in-endless-progress Notations that would freeze the soul. But it's no secret that the ice- man has, if not exactly melted, at least softened into semi-freddo. He conducted the first four sections of Notations - little pieces for large orchestra - in Edinburgh's opening concert last Sunday, and they positively smiled with joy - dancing through what once seemed austere but now seem garish tributes to Messiaen, and revelling in the Stravinskyan barrage of Notation No 4. The robust playing of the Gustav Mahler Youth Orchestra at Usher Hall proclaimed it as a virtuoso exercise in instrumental colour.

There had been mutterings in festival cabbals about the appropriateness of entrusting so high-profile a platform as the opening concert to a mere youth orchestra, but the fact is that these Gustav Mahler players are an elite, pan-European corps whose youth barely registers except in the most advantageous terms. And there is, anyway, a special energy whenever a good youth band tackles Stravinsky's Rite of Spring which was the culminating item on the programme. One of Boulez's longstanding calling-cards, it was electrifying: softer-sculpted maybe than we've heard from him of old, but with the underlying iron control and mastery of detail unequivocal. Some things aren't meant to change.

Another thing that doesn't change at Edinburgh is its commitment to a nucleus of favoured artists who get invited back year after year and are part of the reason why the anniversary spirit of this 50th festival seems unremarkable. Revisiting the past has become an annual occurrence. Of course, you can't complain too bitterly when the artists are of the calibre of Andras Schiff, who played all three Bartok piano concertos at Usher Hall in a dazzling display of brilliant, buoyant and immaculate technique. The whole thing amounted to a Hungarian away-match, accompanied by the Budapest Festival Orchestra whose generous playing and radiant warmth - vestigial of that old-time, well-upholstered central European sound, but fresher and more vital - makes them easily the best ensemble of their kind in Hungary now. Ivan Fischer, their conductor, delivered the most whimsical collection of encores I've ever heard. But the correlative of his odd caprices is charisma, which he has in quantity. His opening night with Schiff was easily the highlight of the week. Which wasn't quite as I'd expected.

I'd thought the highlight would be Mark Morris's new production of Rameau's opera-ballet Platee at the Festival Theatre, which promised to be an event and, in some ways, was. Rameau rarely surfaces on British stages; Platee is a curious piece of knockabout comedy - not the sort of thing 18th-century French opera normally confronted - that parodies the conventions of its own time with outrageous daring; and Mark Morris is, these days, an event in himself whose flop at last year's Festival (a tacky Orpheus and Eurydyce) has been wiped from the record by the genius of his subsequent L'Allegro at ENO.

But Platee turned out to be a qualified triomph de camp: jokily cruel in its story of self-deluded water nymph too ugly to be marriagable, and the stuff of Gilbert & Sullivan but for the fact that Rameau set the nymph as a man in drag. Morris's idea of relocating the action to an aquarium is fun, Isaac Mizrahi's fishy costumes a joy; and Jean-Paul Fouchecourt's idea of Platee as a submarine Miss Piggy a priceless synthesis of the grotesque and sympathetic - nicely sung too, and about as near as you'll find these days to the specialist haute contre voice (a very high tenor) for which the role was written.

But somehow, all this doesn't gel into a complete experience. Morris's priorities are clearly weighted toward movement rather than singing, which disturbs the balance of the piece. Few of the vocal soloists make much of an impression; the chorus are relegated to the pit; and although Nicholas McGeegan gets strong, clean sound out of the Royal Opera Orchestra, it feels somehow subsidiary and disconnected to the staging.

As the first Royal Opera enterprise of its new life on the road, Platee signals a shift in culture - towards a big budget equivalent of Opera Factory. That may prove interesting. But only if the company's integrity stands firm.