<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type"> <title></title> </head> <body bgcolor="#ffffff" text="#000000"> You are quite wrong David.  The formula, and the approach for arriving by calculation at a change in pitch resulting from any given change in length is entirely adequate.  I already went down the road you hint at with several of the physics guys and gals on both lists and Galembos paper is where all that ended up. As for your two different strings below... of COURSE  a similar change in length will affect differently two dissimilar strings that were originally tuned to the same pitch. What that has to do with any of this I am sure I dont know... but even if it did... you could still calculate the changes in pitch each of these would make. Again... Calculate the change in length using trig, then the change in tension using Galembo.. (Hooks law actually), and then you have what you need to calculate resultant change in pitch for any given (unwound) string at any given start tension. Cheers RicB <blockquote> Sorry, but it's not quite a complete enough formula for purposes of this discussion.  When comparing two strings that produce the same pitch but with different tensions, either the original length will be different or the diameter will be different (or both), thus a similar change in length will yield a different change in tension and thus pitch.     David Love davidlovepianos at comcast.net <a class="moz-txt-link-abbreviated" href="http://www.davidlovepianos.com">www.davidlovepianos.com</a> </blockquote> </body> </html>