MUSIC / Anything Tuvan do, they can do: Meredith Oakes reports from the Meltdown festival on London's South Bank

The more up-to-date the show, the more antiquated the hype. So Meltdown, the South Bank's new summer festival, was full of events you could 'not afford to miss' conceived in 'the white heat of creativity'. Despite this, people came. They came in such numbers to hear the Tuvan overtone singers late on Sunday afternoon that the concert had to be moved from the Purcell Room to the Queen Elizabeth Hall.

There's nothing avant-garde about the Tuvans. Their country lies between Mongolia and Siberia, near Lake Baikal but with a mountain range between. The two visiting brothers, Nikolai and Valery Mongoush, wore horsemen's boots, Asiatic belted smocks and those fairytale hats with stalks curving up from them. But overtone singing has fascinated a number of modern Western composers, among them George Benjamin, who put together the musical side of Meltdown effectively. Tuvan overtone singing, unlike that of Tibet, can be secular and lighthearted: wedding songs, limericks, songs about favourite horses. The tunes are sometimes euphorically major and Chinese, sometimes danceable and Russian, but never very fast, as the overtones are heard best in long syllables. And the overtones were astonishing. The high ones formed loud seraphic whistling descants over the basic tunes. The low ones sounded like a magic voice coming out of the ground an octave below. The brothers' confident goodwill charmed everyone. Meltdown melted out from music into film, dance and installations: all the films with Takemitsu scores were shown; there were experiments in silent-film accompaniment by George Benjamin and Benedict Mason; and the surroundings were enlivened by pale flame-shapes in the form of flags and ice-carvings. Low-key in a fragile way.

On the other hand, next year's festival will be presided over by Louis Andriessen. The music risked Darmstadt-type overload but was saved by a preponderance of good pieces and by the excellent playing. Germany's Ensemble Modern on Friday night brought an internationalist programme which included the premiere of a piece commissioned by the South Bank, written by the Canadian Denys Bouliane, entitled Deutsche Landschaft and shot through with American and Latin American echoes. It was a speedy ebullient thing, brass, woodwind and strings cutting each other up, a traffic junction of swoops, sighs and jabs: the sound world post- electronically subtle and rich, as with so many of the pieces chosen by Benjamin. A muscular icebreaker: like Alejandro Vinao's Latin-American-explosive Marimba Concerto which received its first UK performance at the expert hands of Robert van Sice and the London Sinfonietta on Sunday night.

One highlight of the long but always energised Ensemble Modern evening was the Chamber Symphony of newcomer Thomas Ades. A complicated percussion phrase ran through the centre like a repeating melody, creating rhythmic interplay as the other instruments stepped in. The texture was quite sparse but the sounds glided, looped and bubbled in a shapely, fluid continuum. Transcriptions of player piano pieces by Conlon Nancarrow were another welcome surprise. Hyperfast florid runs on woodwinds and several kinds of keyboard, feats of offcentre counting: exhilarating.

On Sunday night the Ligeti playing of the Sinfonietta's piano guest Pierre-Laurent Aimard was memorable. But the piece that will stay in my mind is Serendib, by Tristan Murail: graceful, coherent, wobbling microtonally like images on water, and halfway through multiplying trillwise into a weightless area of bright, shrill sounds.