London Schools SO/Segerstam, Barbican, London

Long a byword for polished and inspirational concerts, the London Schools Symphony Orchestra was for once deserted by its usual large audience.

Long a byword for polished and inspirational concerts, the London Schools Symphony Orchestra was for once deserted by its usual large audience. Could it have been the prospect of Leif Segerstam's Symphony No 113? Even in the unlikely event that they had heard some of the other 112, LSSO supporters are usually willing to give novelty a go.

More likely is that London hardly ever witnesses this unique composer-conductor's extraordinary musicianship. Larger than life in everything except height, Segerstam has run parallel careers as pianist and violinist too. The symphonies aren't miniatures either, though he has ingenious ways of sharing the creative work with the performers.

For an orchestra of learners, the situation is much more involving than making sense of somebody else's instructions. Segerstam's score is like a minute analysis of a symphony, setting up overall proportions, the nature of the material, the way to develop it and the goals to aim for. The players have to make decisions about detail and timing. Segerstam even requires that there should be no conductor, and he spent the performance lurking at one of the symphony's two pianos while the orchestra, with no visual cues from him and a minimum from anybody else, kept together mainly by using their ears.

It worked wonderfully well. The various sections' music is carefully designed so that clashes are almost impossible, and the deliberately out-of-sync passages are quite easy to follow. It all adds up to a sense of free-flowing growth towards several widely spaced climaxes. What is missing is any attempt at sustained fast music, and on this occasion the symphony played its full hand well before the half-hour was up. Yet it still had more to say about music-making than the average fully-notated premiere foisted on a schools orchestra.

Segerstam's rostrum charisma worked its spell in a dynamic performance of the Symphony No 4 by Carl Nielsen. Famed for its duel of timpanists in the finale, the symphony can up to that point sound Nielsen's least coherent. This performance didn't do enough to clarify matters, and its relentless loudness meant that the great moments suddenly materialised out of a fog instead of sounding like long-sought arrivals.

Best were the Sibelius items that began and ended the concert: Riikka Hakola's powerful but sensitive dramatic soprano in Luonnotar, and the big tune of Finlandia, which went with an ecstatic spontaneity.