CLASSICAL MUSIC City of London Sinfonia: Playing in the New The Barbican, London

Conversation overheard at the "Playing in the New" weekend, feting the 25th birthday of the City of London Sinfonia: "Are these [the CLS] the boiler-suit people?" "No, that's the London Sinfonietta." The exchange perhaps highlights the problem between orchestras and audiences: too many ensembles, not enough distinguishing characteristics. By celebrating its birthday with four concerts of contemporary music, the CLS was indeed in Sinfonietta-like guise (but not boiler suits). You could have seen the whole weekend for a mere pounds 14, but by and large audiences were depressingly small. Nothing new there, of course: maybe what matters is the quality of attention, which seemed genuinely alert.

The weekend began on Saturday afternoon with the world premiere of Blowing the Fuse, in which composer Priti Paintal threw players from the CLS together with her own ensemble Shiva Nova, providing space for composition and improvisation to work together. The work built outwards from phrases that had the elemental simplicity of good show tunes, allowing Eastern and Western instruments to mix their distinctive colours. At times the small string section presented an insistent drone against which the solo instruments bounced their free-flowing ideas; at other moments the whole ensemble united in jaunty choruses that acted as a kind of structural brake on the improvisers' flights. The piece as a whole communicated an infectious pleasure in the shared act of making music happen.

Later that evening, Richard Hickox, CLS founder and music director, conducted a programme of contemporary pieces, unnecessarily prefaced by Britten. Barry Guy's After the Rain here sounded angrier, more agitated than on the orchestra's recording; while John Tavener's Agraphon was both serene and fiery, soprano Patricia Rozario encompassing the quasi-Levantine lines with expressive ease. In between, Minna Keal's Cello Concerto juxtaposed broad lyricism and pained agitation. If orchestral textures seemed thick, sometimes almost impenetrable, Alexander Baillie's cello managed to clear a way for itself.

"Playing in the New" reached its climax on Sunday with a programme of no less than four premieres (to be broadcast by Radio 3, 18 October). Simon Speare's New Ribbons, chosen from submissions to the Society for the Promotion of New Music, proved to be a brassily exuberant concert overture, or theme tune perhaps. Skilfully layered, neatly tailored, it did what it needed to do in five minutes, then stopped. If only all new music were so concise. By contrast Diana Burrell's Dunkelhvide Manestraler, with soloists Catherine Wyn-Rogers (contralto) and Nicholas Daniels (cor anglais) felt protracted, in part no doubt because Burrell chose to set Tove Ditlevsen's original Danish, a sure barrier to communication.

No such problems with Tavener's The Hidden Face, a stark confrontation, observed from the back of the stage by whispering strings, between oboe (Nicholas Daniels again, in snake-charmer mode) and counter-tenor Michael Chance, called on to produce eerie microtones. Unmoved by Tavener's demand that we "cast off all the received, intellectual, sophisticated garbage", I found the piece almost operatic. With the composer himself in among the double basses, occasionally helping out with conducting duties, Barry Guy's Fallingwater was a glittering orchestral kaleidoscope, according the players a measure of freedom within a rigorously controlled structure. Its procedures were complex, but it communicated readily, and brought the weekend to a fitting close