[CAUT] Wire Stretch

[RicB]

I just posted a link to a such an approach.  In the end its quite easy.  
You first find the change in tension a give change in deflection yields, 
and then you have all you need to use standard frequency formulas.

 Delta T = ES (Delta L / L). 

Then calculate for the new frequency with your known wire diameter, 
speaking length and tension and the so called K constant... which in 
this case is

    (Pi * string density / 981)

f = Sqrt(T/(L^2*d^2 *K)

Ok ?

Cheers
RicB

Is there some source or "relatively easy" formula for calculating how much a
string must move through a termination point to produce pitch change?    I'd
like to have some tiny bit of basic information so that in describing pitch
corrections of significant distance I can use the information to explain the
likelihood that the piano will need a retuning in the near future.
thanks
les bartlett