Pianomania: Notes in the key of madness

The story of concert pianism is strewn with madness – how could it not be, when the demands of the job are so insane? What sane person would build their life round juggling millions of notes from memory and without safety nets? Last week saw the release of Pianomania, a documentary film about that prince of piano-technicians Stefan Knupfer, in which the madness underlying the method of one of the world's greatest virtuosos is laid bare. Pierre-Laurent Aimard is going to record some Bach, and wants a piano that can combine the intimate effect of a clavichord with the deep sonority of an organ and the blaze of a concert Steinway.

Watching Knupfer trying to square this circle becomes maddening it itself: no wonder he has a staring, hunted look. He puts in extra felts, then is told to take them out. He spends a month preparing one piano, then a month preparing another, and is then told to put them on the stage side by side. Aimard's demands reflect a high degree of neuroticism, though Knupfer loyally denies it: "Let's say he's just – specialised."

Yet two weeks ago, Aimard fluffed his entry so badly in a Prom that everyone on stage was given the jitters. No doubt the sound he was pursuing for his Bach recording was genuinely wonderful, but out in the real world such fastidiousness is completely beside the point.

'Pianomania' is out now