Of all the psychologically challenging concerts in this year's festival I think this takes the chequered flag: It was at the edges of most people's perception of musicality and provocative to the point of being extreme from a linked video aspect.

Kate Ryder, piano and keyboards, explored many sounds and effects few would expect a piano to produce, with, of course, the aid of various objects restricting hammer and string movement in the instrument. Blending with that, in an almost bizarre contrast, was Jane Chapman, on an untouched harpsichord, a player of amazing vitality and technical dexterity.

Amazingly, the whole combination worked. The mixtures of sounds led to a mix of emotions. The listener has to name the emotion and that is the difficulty.

And don't rule out the visual aspect of video on a large screen. That, sometimes, was more of an irritant.

They both have in their heads built-in microchips; how else could they have achieved so accurately some of the most complicated and precise timings.

They are each, in their own ways, elegant players; but I'm not sure whether the sounds they produce are elegant.

That elegance, or otherwise, is, like so many things, in the eye, or rather in this case also, the ear, of the beholder.

A brave concert to stage. And the last word from a 12-year-old girl who sat next to me. "Did you like it," I asked. The reply: "Very much."

Reg Burnard