<!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"> Hi Michael My calculations show that a change in string length due to a change in offset angles that would be caused if the string was caused to rise or be lowered on the bridge pins causes a clearly significant pitch change. To the the degree that poor seating can get into this picture I would have to disagree with you. As far as the span change isolated from what change might take place from offset angle lengths are concerned... I would tend to agree.. but then I havent sat down and calculated anything along these lines yet so I would hesitate to say for sure. You raise the idea that the poorly seated string / loose bridge pin may cause an in phase movement that goes in all vibrational directions at once, causing the string to think it is longer then it is. Making the coupling more firm then would eliminate this in phase motion and actually raise the pitch of the string. Which kind of goes in the opposite direction as we experience when seating strings. As far as the reaction given by Ron to all this in the direction of the loose bridge pins are related to false beats is concerned,  I have to respectfully disagree. For the first it has nothing to do with Micheals point at all. Secondly because well..  simply based on the fact that one can observe far to many exceptions in the case where loose pins and recessed edge are present.  When somebody can explain clearly to me why this condition can statistically be seen only as randomly associated with the occurrence of single string beats I will be insterested.  On another note... the horizontal mode as a <<proof>> for the loose pin idea is just too easy to dismiss. One can measure in phase movement in any direction... not just the horizontal.  It is when the assembly as a whole decides to fool the string into thinking its longer then it is that single string beats can occur. I would also like to point out that just a week back I got a note from one of the most respected piano physicists in our world stating outright that  single string beat as relates to in-phase movement at the bridge must be seen in terms of the entire bridge / bridge pin assembly... and included in this the soundboard area immediately adjacent to the bridge foot. Cheers RicB <blockquote>It seems to me that any change in the length of the string because of poor seating on the bridge or  deformation of the bridge surface, would be insignificant.  However, that said, I believe that a poorly seated string coupled to the a loose bridge pin actually lowers the pitch because it is as if the pulse traveling along the string suddenly thinks that the bridge pin is part of the string and thus a longer string length. Michael Wathen -- </blockquote> <div class="moz-signature"> </div> </body> </html>