For all musicians, the relation with sound is a central part of making music: one of the primary aims of every performer is, in fact, to achieve an optimal “control of the sound”.
But the term “control” risks being misleading. Our conception of sound should never be external to the music, and rather than “control”, we should speak of the “creation” of sound: the sound we are looking for is nothing other than what we spontaneously know we are able to produce, if we succeed in removing all the factors (physical and mental) that might stand in its way. People often think of sound as the consequence of the player's movement, or in any case of the vibration of the string or of the air. Perfectly true, but it seems more useful to think the other way round: the movement we make to produce that particular sound is in turn the consequence of the sound that must already exist in our mind.
The first thing we must focus on is, then, our idea of the “right” sound for that given passage. Often, though, students don't start from there, but rather from a specific physical gesture, that they, or their teacher, believe to be the most appropriate. Whatever the case, the resulting sound will risk being an end in itself, or not sufficiently intense, if not supported by a strong idea in the mind of the performer. On the other hand, an emotional stimulus that arouses a particular expressive state within us, is sometimes enough to help us find the sound we want, instantaneously and without any “controlling”.
The great pedagogue Karl Ulrich Schnabel was a master of the art of helping the pupil to obtain the sound he/she had in mind, totally overriding any question of muscle control. For instance, I remember a lesson when I was playing a Sonata by Schubert. There was a theme marked ppp for which I was striving to find a sonority bordering on silence, without sacrificing its due intensity. Schnabel solved the problem with a simple phrase. He said: “here you must tell me a secret”. So, all I had to do was to think of the expressive situation to find the right gesture instinctively, to obtain a sound that was profound and meaningful, yet bordering on silence. Later, looking back on what had changed in my gesture, I realized that I was staying totally attached to the keyboard, pressing the key down to its very bottom with the tips of my fingers, but at a minimal speed. But if Schnabel had asked me to do this by describing the technical procedure then I certainly wouldn't have attained the same result, and maybe I wouldn't even have been able to do what he was asking! Instead, he managed to trigger the appropriate psycho-physical reactions that helped me to discover by myself what was “my” way of obtaining that sound. Another example: in the final chords of a Beethoven Sonata I was looking for a brilliant and affirmative sonority, but I was just getting an aggressive and indecorous timbre. An experienced but unimaginative teacher would have said: use a more elastic movement, placing the weight closely with an oblique and not perpendicular angle of attack. Schnabel simply said: «“Here it's as if you were saying “Die!”. Try saying “Live”».
The mental conception of the sound, just like that of the phrase and the structure of a piece, must therefore be already very focused before you play it, and always associated with an emotion or with the evocation of things, images or situations that surpass the pure technical gesture. At times it might prove useful to think of the timbres of other instruments (strings, flute, oboe, timpani, bells) or the sounds of nature (birdsong, wind, rain), specific colors, or even physical substances (liquid sound, airy sound, bronze sound). This will never be totally materialized in the real sound we obtain on the piano, but it will help us to recreate as best possible our idea of the sound, and to transmit it to the audience with the greatest intensity. The great artists, gifted with true charisma, are those who succeed in recreating in listeners the same timbral (and thus affective) impression that they themselves had imagined beforehand.