Tone Production by the Pianist

[John Dorr]

In your experience and philosophy can different pianists create different 
tones on the same piano, at the same volume (velocity of the hammer striking 
the strings) with different touch techniques?  It seems to me that the player 
always throws the SAME weight at the SAME target and doesn't have a direct 
connection with the string at the moment of impact, so would therefore have no 
control over what the tone generated by the instrument is, except and unless 
they could somehow control the checking point of the hammer so that it 
influenced a very small part of the acoustics.  Shouldn't MY (drummer's 
touch!) mezzo-forte middle C sound exactly like Chick Corea's on the same 
instrument?

I ask because I have a piano teacher friend who insists that SHE and her 
students are ultimately in charge of tone.  And when I ask her to demonstrate, 
she really can't.  She just plays louder or softer on her Steinway.  Sure, the 
tone changes with volume, but she can't prove to me that she's capable of tone 
change at the SAME volumes.  She holds her ground, though, and says, "Well I 
can't do it right now, but I know that sometimes when I play I can make it SO 
BEAUTIFUL, and other times..." and goes on to say that it has to do with the 
"love" she inputs to the keys.  I responded that I thought it was her 
emotional attachment to the music at the moment and the voicings her fingers 
were able to  respond with, by which I mean each individual finger is capable 
of its own velocity (and therefore TONE character) that expresses the music 
according to her emotional interpretation.

Sorry to get so long-winded about it.  It's really a simple question, isn't 
it?        Does the pianist have the ability to influence tone character 
differences at the same dynamic level?  If so, can you explain the physics of 
that?