Duplex

[Ron Nossaman]

>>And you have determined this how?
>
>A rear duplex behind the actual speaking length and an adjacent rear 
>duplex (ie. on an adjacent note) are tuned to the same harmonic of 
>the speaking length being tested. Everything else on the piano is 
>muted out (tape is the best for this purpose). One of the rear 
>duplexes under test is muted while the speaking length is played 
>heavily then damped. Repeating this experiment with each duplex will 
>demonstrate that slightly more energy gets through to the duplex 
>which is connected directly to the speaking length. I must add 'hear' 
>that this type of experiment has to be middle of the night stuff when 
>things are very quiet. The amount of energy that crosses over is 
>pretty damn small.
>
>As I mentioned yesterday, I suspect that the bridge pins are flexing 
>in the bridge cap as the string tension cycles in response to the 
>string position (as it vibrates). I believe that this allows a small 
>dynamic tension deviation to leak through to the rear duplex. I am 
>only speculating that less energy would get through with the a bridge 
>agraffe (I have not tested one), but I think it is reasonable to 
>assume that it would be less inclined to flex in response to minute 
>changes in string tension as the string vibrates. I hope this makes 
>sense, its hard getting concepts across without being able to wave 
>our arms about as we speak.

Ah yes, that is a terrible handicap, isn't it? These things are so much
easier with a little well directed flailing. And speaking of flailing (keen
segue, huh?), even with everything else taped off here, wouldn't that one
excited string move the bridge and soundboard, and string plane enough to
move the duplex enough to...? - without any energy having bled past the
bridge pins at all?
 
Ron N