impedance and empericism

[Ron Nossaman]

>Also:
>If the soundboard swells, what makes the pitch go up? Doesn't the deflection 
>from horizontal increase, and doesn't the string get longer?

Yes, but the tension goes up too, and the length increase doesn't quite
cancel out the tension increase so the pitch rises. Also, the lower the
break%, the more the pitch changes with tension increases, which is one of
the reasons the low tension low treble goes out so far with humidity
swings.    


> If the tension 
>is then lowered on that string, doesn't the string remain longer because the 
>sbd is in a different position? 
>
>Bob D

Yep, in fact it gets even longer as you lower the tension because the
bearing load goes down on the board and it rises still more. Not a lot, but
some. Now what does a slightly longer speaking length at higher tension,
and the same pitch as before the humidity increase, do to the
inharmonicity? Now why do people report different inharmonicity profiles in
the same piano in different seasons?

Good observation Bob.

Ron N