In an excursion I made into another music forum, I read this:

Originally posted by Noseeum
As you have no doubt noticed, harpsichord sound varies much more widely than piano sound.
I know nearly nothing about the mechanism of sound production in a piano, except that some thirty parts are involved for each key (the action), let alone the harpsichord. But application of logic along with some rudiments of acoustics allows me to draw some conclusions. So I wrote:
How is that, Noseeum? Would you care to expand the concept? If we agree that sound can be characterized by three elements and only three elements, namely, pitch, intensity and timbre, then we have: pressing a key in either instrument determines the pitch, and it also determines the timbre, because in such complex devices as keyboard instruments are, the sound comes "prefabricated". I mean, pressing a button (key) just triggers a complex mechanism whose output is the sound you hear. The clavecinist or pianist does not intervene in the production of sound, as is the case in a violin, for instance, which being a much more primitive instrument, lets the player to actively control the quality of the sound. In this way, each key in either instrument, harpsichord or piano, has an associated predetermined timbre, which no player can alter (the use of the pedal introduces a slight complication here which for the moment I'll shall not consider). There is only one variable left: intensity. And here you have that the piano has a huge dynamic range, which makes it possible to play from a pppp to a ffff and, in fact, an infinite number of dynamic levels.

I'm sure most of pianists would disagree with this explanation, but I would only be willing to hear speak a pianist who has grasped the elements of acoustics (these principles are indeed taught at conservatories but the professional pianist will nonetheless insist in that he controls the timbre in his instrument).
My whole refutation would lack meaning or the greater part of its force if the poster would consider that a pianist has any kind of control over timbre. What do you, fellow BRSers, think about this matter?