<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=us-ascii"> <meta name=Generator content="Microsoft Word 10 (filtered)"> <style>  </style> </head> <body bgcolor=white lang=EN-US link=blue vlink=blue> <div class=Section1> <a href="http://www.1728.com/unknwn2.htm">http://www.1728.com/unknwn2.htm</a>   Maybe this will help.  Are you trying to tell me that you can’t solve for how a resulting change in length on a given string will change tension and thus the frequency at which the string will vibrate?  You are incorrect.       <div> David Love davidlovepianos@comcast.net www.davidlovepianos.com </div> -----Original Message----- From: caut-bounces@ptg.org [mailto:caut-bounces@ptg.org] On Behalf Of Richard Brekne Sent: Monday, June 11, 2007 2:39 AM To: caut@ptg.org Subject: [CAUT] pre-stretching new string?   David, No.. you can not calculate for a variable with two unknowns.  If you want to solve for pitch as you suggested in your earlier post.. you first have to have all the other variables in any equation you use to do so. Rewritting the tension formula still includes both tension and length, and when you change length you change tension, resulting in two unknowns, both of which must be known before you can solve for pitch. The equation for solving for this accompanying change in tension has been posted several times. I post it again for your edification. <a href="http://www.pianostemmer.no/files/stringdeflection/brekne.doc">http://www.pianostemmer.no/files/stringdeflection/brekne.doc</a> If you have a formula for arriving at change in pitch for change in length directly without solving for the change in tension first... please share it with us.  Cheers RicB Of course you can.  The pitch (frequency) at which a string vibrates is a function of length, diameter and tension.  A change in length will result in a change in tension which will result in a change in pitch.  It's a complex equation but it's not trigonometry, it's algebra.  You can certainly rewrite the formula to isolate pitch, or tension, or length, or diameter.  That's the beauty of Algebra.  The miraculous is simply the unexplained.    A strings vibration period (I assume you mean frequency) will not be altered by the soundboard.  The string continues to vibrate at its given frequency until it stops no matter what the soundboard does (though it does influence how long it will vibrate for).      David Love davidlovepianos at comcast.net www You can not solve for change in pitch directly by re-writting / re-arranging the formula for string tension. You can not because any given change in length automatically carries with it a change in tension i.e. you have two unknowns.... tension and length.  Length change is easy to calculate with the simple trig talked about. But that leaves you with an unknown change in tension still. You could measure pitch of course and calculate the new tension that the new length resulted in...... but aside from being the long way around... we are solving for pitch.  Its easy enough to do... just calculate the change in length, and then the resultant change in tension. Then you have all the variables you need to calculate for resultant pitch. Thats.... for a string whose vibration period is truly reflected by the soundboard... and not altered significantly due to any stiffness issues... which just came up and of course sheds a different perspective on everything to the degree that thought ends up being significant itself. Cheers RicB David Love davidlovepianos at comcast.net <a href="http://www.davidlovepianos.com">www.davidlovepianos.com</a> -------------- next part -------------- An HTML attachment was scrubbed... URL: <a href="https://www.moypiano.com/ptg/caut.php/attachments/20070610/c137e62e/attachment.html">https://www.moypiano.com/ptg/caut.php/attachments/20070610/c137e62e/attachment.html</a>     * Previous message: [CAUT] pre-stretching new string? </div> </body> </html>