Classical: Back to Hungarian roots for an earthy Bartok

AT WHAT point does the child prodigy hatch, so to speak, to reveal the fully-fledged musician within? At what point, if ever, does astonishment at what they can do become recognition of why they do it? Sarah Chang has been with us for a lifetime - or so it would seem - but at 18 she has truly come of age. There is still the girlish glee at tricky passages well-dispatched, but she has grown, and her sound has grown, because now she has something to say. From the outset of Bartok's Second Violin Concerto in Wednesday's London Symphony Orchestra concert she was surprising. The opening melody was heartily, even gruffly, sung. You felt that she knew precisely where in the Hungarian heartlands the piece originated.

The folk elements in Bartok's music need singing even where they are played. And Chang "sang" them in different, often unschooled, voices, with judicious use of slides conveying very particular intonations. The beautiful plaint that opens the slow movement was an old song, simple and unaffected, almost half-remembered. Chung lent it a primitive sophistication - which is the contradiction at the heart of Bartok.

Most concertos set up their primary opposition between the soloist and the orchestra. In this work, it's soloist versus soloist, realist versus dreamer. Chang caught it beautifully. She wasn't afraid to be plain, even downright unlovely, while the fantasy went beyond the merely cosmetic. Sir Colin Davis and the orchestra were big, bold and - wherever necessary - uncouth.

All of which seemed like very bad manners indeed in the wake of Elgar's Serenade for Strings (now, that's what I call capricious programming). Not that there was anything genteel about Davis's reading, or the enormous string band he chose to deploy. It was a mighty, sumptuous noise, but a little like outing an essentially salon piece and insisting that it behave like one of Elgar's butch symphonic works.

Beethoven similarly well-upholstered. His Seventh Symphony emerged like a heavyweight from eight rounds with Richard Wagner. Not so much "the apotheosis of the dance" as a knees-up in Valhalla. Even allowing for Davis's penchant for the bigger-is-better, Napoleonic view of Beethoven, large forces (which Beethoven used in his performances of this symphony) need not mean dense and opaque texturing. Little was revealed here beyond the broadest outlines of the piece. Double woodwinds were absorbed into the string sound, with much detail simply lost. If that great finale is the engine-room of 18th-century symphonic music as it powers into the 19th century, then I want to hear more of the mechanism. Divided violins would have helped to delineate the rhythms, not least in the thrilling shoot-out in the coda, but the problem went deeper than that. Size matters? Not on this showing.