On improvisation - Improvisation for me is a kind of philosophy, a way of structuring time in relation to material objects, and, at the same time, 'tending' those objects. I'm interested in the history of the instruments I play, which feeds directly into their phenomenological relation with the body; they're not neutral but express both the internal world of the instrument, and the resonances of the room, as well as the manner of the body's fit. The oud for example is awkward, and if you lean your head against it, the vibrations dominate, as they do for example on the viola. All of these instruments, even the electric one, are acoustically much more complex than people realize - the bridges vibrate and twist in complex patterns, for example, especially with bowing. Think of the instrument as a living thing (that fallacy again); affecting one area or dimension or section of it, affects all the others. There's an amazing book, The Violin Explained, http://www.amazon.com/Violin-Explained-Components-Mechanism-Sound/dp/0198167393 - which goes into the details of just this single instrument.
Finally I've noted subjectively, because I play very fast, that time seems to compress when I'm playing - this is a very real sensation - I'll do something that feels slow, and seems to take hours, and it will all be over in ten minutes or so. So I've had to adjust my time sense consciously, realizing that when I'm playing at tempo X, I'm hearing a different tempo than the audience. -