<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <html> <head> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=us-ascii"> <meta name=Generator content="Microsoft Word 10 (filtered)"> <title>Message</title> <style>  </style> </head> <body lang=EN-US link=blue vlink=blue> <div class=Section1> Like Ron said, termination of the bridge top and pin need not be exactly the same, in fact, it’s probably best to err on the side of having the notch cut slightly behind the pin to prevent the edge from migrating out beyond the pin over time as the bridge top indents underneath the string.  With the pin angled at some 20 degrees the string will not ride up during its normal vibration and create problems as you describe.  Bridge pins are necessary to prevent lateral movement of the strings especially since the hitch pins are not always in an exact straight line with the bridge notch.  With single strings on a guitar, you don’t have that problem.   The bearing angle through the capo (or the pressure bar) lessens the need for pins on that end except, such as in the bass on certain uprights, where the tuning pin location creates an offset.  BTW, a lack of adequate counterbearing through the capo can create problems with string migration side to side as you see on some lesser uprights and grands, especially if the layout of the tuning pin array doesn’t quite match the needed spacing of the strings across the capo.    <div> David Love davidlovepianos@comcast.net www.davidlovepianos.com </div> -----Original Message----- From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On Behalf Of Geoff Sykes Sent: Sunday, January 13, 2008 10:51 PM To: 'Pianotech List' Subject: RE: String termination question   <div> David -- </div> <div>   </div> <div> I believe I used the term inharmonicity incorrectly. My apologies. Inharmonicity is caused by the fact that the string doesn't terminate at an exact or perfect point like, say, a hinge, but rather through a bend that does not uniformly reflect the multiple waveforms of the different partials created within a vibrating string at a unique point. </div> <div>   </div> <div> I don't think the primary purpose of a bridge pin is to prevent the string from sliding around on top of the bridge. Like a guitar or other stringed instrument that possibility is minimal. But just the same, because of the high tension and subsequent high partial content of a piano string the tolerance of any string movement across the bridge would be much lower and a bridge pin is very helpful in that regard. </div> <div>   </div> <div> What I'm referring to is the need to make sure that the edge of the notch on the bridge exactly matches the side of the bridge pin so that the string termination at the bridge is the same in both the X and Y axis. If it were not the same then the string is literally a different length on one axis than it is in the other. Since a string moves in all directions when vibrating, not just up and down, if that termination is not exact then the partials created in one axis are different than in the other, creating beats. This is one reason why we make sure strings are seated correctly against the bridge itself, and hope that the bridge notching and the pin placement has been done accurately. It's another reason, in addition to stability, why the movement of bridge pins in cracked bridges is such a problem. </div> <div>   </div> <div> So I understand why matching the termination points for both X and Y axis is important at the bridge. What I don't understand is why it's not a consideration at the opposite end of the string. And like I said, since this is a centuries old practice it's obviously not a significant problem or else we would see X and Y axis termination at both ends of the string. I'm just curious as to why it's not a problem at the agraffe and capo bar end of the string. </div> <div>   </div> <div> For a better understanding of my question check out Reblitz page 113, "Ringing, Jangling or False Beats in Treble Strings." I pulled out my copy, (2nd ed), and looked this up and then posed my question here because Reblitz just didn't address the effectiveness of the agraffe/capo bar termination. Perhaps, as you suggest, it's because the counterbearing is so severe that it's just not a problem. I'd just like to understand it a little better. If that's possible. </div> <div>   </div> <div> -- Geoff Sykes, Los Angeles </div> <div>   </div> <blockquote style='margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt'> <blockquote style='margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt'> <div>   </div> </blockquote> </blockquote> </div> </body> </html>