Boulez hits the right keys

At the conclusion of the South Bank's Celebrating Pierre weekend on Sunday, Pierre Boulez's 75th birthday, it took Daniel Barenboim, from the stalls, to initiate even a modest standing ovation among a Royal Festival Hall audience that included an unusual number of the great and good. But if our typically British reticence seemed inappropriate, the man whom some consider the world's greatest living composer had at least celebrated with us, rather than elsewhere.

I missed the opening, evidently stunning, piano recital by Pierre-Laurent Aimard. On Saturday evening, also in the Queen Elizabeth Hall, the London Sinfonietta played two works by the programme's conductor, George Benjamin, as well as three by Boulez himself. The latter included the UK premiere of Anthÿmes 2, the 1997 version for solo violin and live electronics of an unaccompanied violin piece composed six years earlier. The work seemed too protracted, lacking the satisfying sense of shape its composer usually creates despite the tendency of his typical method of "proliferation" to refuse more conventional development or closure. No reflection, though, on the soloist Clio Gould, who delivered Anthÿmes 2 with considerable dramatic and technical flair. I also enjoyed Benjamin's five-year-old Three Inventions for Chamber Orchestra, not least for its marvellously musical and witty control of structure, complete with some subversive, effective endings.

Pacing and development are no less crucial to the success of short pieces. Most of the 12 composers involved in the sequence of tributes to Boulez, "Notes for Pierre" - played, with passion and precision by the pianist Rolf Hind - unwrap their gift with skilful timing as well as to establish an immediate identity. I particularly admired Unsuk Chin's Grains, which expertly assembles its flourishes and occasional, rather Boulezian resonances around a repeated single note, and Wolfgang Rihm's plaintive Auf einem anderen Blatt, with its oddly insistent triad and brief final eruption.

When the London Sinfonietta performed Boulez's Sur Incises - his recent, and in all probability still on-going elaboration of Incises, his short 1994 piano piece, using three each of pianos, harps and marimbas/ vibraphones. Last year, I found it intractable, but there were no such problems on Sunday, or at least far fewer. For whatever reasons - including a better performance, perhaps, conducted by Pierre-André Valade - this "Hall of Mad Mirrors" (as Brian Ferneyhough once dubbed the results of Boulez's techniques) now suddenly made compelling, eloquent musical sense.

Roger Wright's public discussion with the composer that evening was not as probing as it might have been. But the concluding, 68-minute performance of Pli selon pli (1960 and probably still tinkering), made absolutely riveting listening. Though its pivotal soprano soloist, Valdine Anderson, occasionally seemed ill at ease, her pure, focused tone is perfect for the elaborations Boulez conjures from Mallarmé's allusive and elusive verses. Under the typically revelatory direction of the conductor, an enlarged Ensemble InterContemporain revelled in the teeming inventions and wild, imaginative fantasies that have long made this work seminal.