<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD><TITLE></TITLE> <META http-equiv=Content-Type content="text/html; charset=us-ascii"> <META content="MSHTML 6.00.6000.16414" name=GENERATOR></HEAD> <BODY text=#000000 bgColor=#ffffff> <DIV dir=ltr align=left>Mail me privately, off list, would you. It's a waste of list time for my silly question. Thanks</DIV> <DIV dir=ltr align=left>les</DIV> <DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left> <HR tabIndex=-1> From: caut-bounces@ptg.org [mailto:caut-bounces@ptg.org] On Behalf Of RicB Sent: Sunday, April 29, 2007 6:21 PM To: caut@ptg.org Subject: [CAUT] Wire Stretch </DIV> <DIV></DIV>Hi Les... First let me say I understand your feelings here... but if you get hooked on figuring out this stuff you probably will find you are far brighter at math then you may think now. Secondly let me say that after re-reading your post... this bit of math doesnt quite address what you were asking for. This is about finding the change in string tension that occurs when one deflects or changes the deflection of a string and doing nothing else. Delta is a greek word used in math for <<change in>>  Usually denoted by a triangle.  Not a big thing really. So the first bit below is simply <<the change in Tension>> = Youngs Modulus * Cross Section of the string * << the change in the string length because of the deflection >> divided by the origional length of the string. Not so tough really.. just some multiplication and division. The second bit is much of the same thing Frequency = the square root of (Tension divided by (the length of the string squared times the diameter of the string squared times the strings density constant) You can use McFerrins book to find out a good deal about some important formulas we use.  A bit of head scratching and insistance on digging out your high school pre-calc and algebra books will take you a long ways. I can send you a spread sheet that does all this if you like... Cheers RicB <BLOCKQUOTE> Uh, there's a reason I did poorly in math...........  But I know some folks who can tear this apart step by step.... thanks lse <BLOCKQUOTE>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 </BLOCKQUOTE> No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.467 / Virus Database: 269.6.2/779 - Release Date: 04/28/2007 3:32 PM   <DIV class=moz-signature>-- <IMG src="cid:181133203@30042007-2973" border=0></DIV></BLOCKQUOTE> No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.467 / Virus Database: 269.6.2/779 - Release Date: 04/28/2007 3:32 PM </BODY></HTML>