<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> <meta name=Generator content="Microsoft Word 10 (filtered)"> <style>  </style> </head> <body bgcolor=white lang=EN-US link=blue vlink=purple> <div class=Section1> BTW, the back length is inconsequential to the formula.   <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 David Love Sent: Sunday, June 10, 2007 8:25 PM To: 'College and University Technicians' Subject: Re: [CAUT] pre-stretching new string?   Grin…You will find in the example you listed below that since both speaking lengths are equal, they will both yield equal break point percentages.  While you have to increase the tension in the string with the greater diameter, it also has a higher break point so the break point percentage does not change.  Set up your example using two notes different speaking lengths to begin with so that the BPPs are not equal.  Then run your calculations for an equal change in length.        <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: Sunday, June 10, 2007 3:53 PM To: caut@ptg.org Subject: [CAUT] pre-stretching new string?   Actually... grin... JD's post stopped me up and I broke out my handy dandy spreadsheet and find he is right, and my last post in which I stated <pre style='margin-left:1.0in'>"As for your two different strings below... of COURSE  a similar change </pre><pre style='margin-left:1.0in'>in length will affect differently two dissimilar strings that were </pre><pre style='margin-left:1.0in'>originally tuned to the same pitch."</pre><pre style='margin-left:1.0in'>  </pre> is wrong. Take for example the two following strings.  1:   9 mm Ų, 100 mm long speaking length, 50 mm back length, and 192.3750 lbs 2:   8 mm Ų, 100 mm long speaking length, 50 mm back length, and 152 lbs Both yeild starting pitch undeflected at 2070,6484 hz  and both if deflected 1 mm upwards at the <<bridge>> will have their pitch altered to 2104,7860 hz. Thanks JD.  Spoke to fast in my last. Cheers RicB <pre style='margin-left:1.0in'> </pre> <blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'> <blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'> At 10:11 am -0700 10/6/07, David Love wrote: >Sorry, but itÕs 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. </blockquote> If this were so, then the whole basis upon which musical instruments are designed would crumble.  When you halve the length of a vibrating string, no matter how much strain is on it etc., you double the frequency, and if you stop two unison strings of identical length but of different mass, and thus tension, at the same point, you will make precisely the same change in their frequency and they will still sound in unison.  If this were not so it would be impossible to play a guitar in tune unless the tension of all six strings were identical. According to Wolfenden, if the temperature changes, and one of the strings is well below its yield point whereas the second is close the yield point, then the strings will produce a beat because the less strained string is more sensitive to the change in temperature.  This is easy enough to verify by a simple experiment, which I shall do in the next few weeks once the new workshop is up and running. JD </blockquote> </div> </body> </html>