Herb Hunter wrote:
"To my way of thinking the kinetic energy of the right hand is transferred to the guitar. "
Right, but your right hand doesn't vibrate at acoustic frequencies, let alone those of the higher partials of the strings. Something has to convert the pushes of your fingers or the pick into the frequencies you want, and only those frequencies. This is the job of the strings. In some ways these act like the old fly ball governor on a steam engine, resisting motion outside of a defined frequency band. Of course, the Q value of a string is vastly higher than that of the governor of an engine, so they produce much more exact pitches than the fly balls would.
Strings are very low impedance oscillators; small masses running at high amplitudes. Something has to match that in with the relatively higher impedance of the air in the room. That's what the guitar body does. It's far from having a 'flat' acoustic response, of course, and adds a lot of 'color' to the string tone. One thing this does is allow the player to shape the tone they put out. By emphasizing string partials in certain bands while avoiding others, and controlling the way the string couples with the top by altering their attack, players can achieve a large measure of control over timbre, as well as dynamics, of course.
So there's at least two levels of transduction; finger/pick to string and string to room. You could probably break it down further if you wanted.
That's my take on it, anyway, but what do I know; I'm just a guitar maker.
