<html> <blockquote type=cite class=cite cite>How would = you define "coupling", in this case?  </blockquote> The pin angle combined with the string tension and offset angle forces the string against the bridge top. It's a clamp system. <blockquote type=cite class=cite cite>Does the front edge of the bridge play any role in defining the string termination?  </blockquote> Yes. It's what the pin angle, string tension, and offset angle clamp the string TO, ideally. <blockquote type=cite class=cite cite>If so, how= is that function affected by 1) no contact (string climbing pin- see next quote  </blockquote> Strings don't climb pins unless something is severely wrong, but the termination edge is crushed by cyclic wood dimensional changes with humidity swings pushing the string up and down the pin. It's very possible for a string to be resting on the bridge top and not be touching the notch edge, but it hasn't climbed the pin. It's crushed the cap. At that point, the loose pin flexes and flagpoles and the false beat happens. <blockquote type=cite class=cite cite>2) glancin= g contact with no force </blockquote> Same as above. <blockquote type=cite class=cite cite>3) some downward pressure?</blockquote> At a certain point, enough pressure will be generated at the edge to prevent the pin flagpoling. <blockquote type=cite class=cite cite>  If = it does not, does it have any function other than supporting the bridge pin?</blockquote> The cap supplies the other half of the clamp, as well as supporting the pin. <blockquote type=cite class=cite cite>Are you saying that a string riding up a bridge pin would require BOTH negative downbearing AND near-straight bridge pins?  </blockquote> Probably, in a typical situation. It would take a whole lot of negative bearing to pull a string at a 10° side bearing up a pin that's slanted 20°. <blockquote type=cite class=cite cite> In a= ny case, it's hard for me to believe that you have not encountered innumerable examples of strings which visibly settle downward when tapped (gently). </blockquote> Of course. But it's because you're inducing a curve into the string to force it down to the crushed bridge edge by tapping, not because the string has climbed the pin.  <blockquote type=cite class=cite cite>It's the "clamping" concept I'm having trouble with.  If there is positive downbearing, the need for further clamping would seem somewhat redundant.  </blockquote> Except that's backward. That clamp provides considerably more coupling of string to bridge than does downbearing. Try to pull a string up off a bridge. Now pull the bridge pins, tune it back up to pitch and try again. Without the pins, there's not much keeping the string on the bridge. <blockquote type=cite class=cite cite>If there i= s negative downbearing,  and thus, no bridge loading, what is the purpose of clamping the string to the bridge surface?  </blockquote> Because the bridge surface is there and handy for such a use, and the traditional pinning method is relatively effective, cheap, and easy to build. And since negative bearing in a conventional system isn't a desirable condition, it isn't useful to use it as a standard by which to justify the rest of the configuration. <blockquote type=cite class=cite cite>Wouldn't t= he vibrational energy be conducted to the bridge by the pins, even without the bridge surface contact?</blockquote> Yes. If they supplied a positive and rigid enough clamp, they would then become an agraffe. In a conventional system that isn't in structural failure, the string is contacting the bridge top. <blockquote type=cite class=cite cite>My problem with the concept and terminology of "clamping" is that it encourages an image of the string exerting a vertical pulling and pushing force upon the bridge, which I believe is inaccurate.</blockquote> How can you reconcile this belief with the belief that strings climb bridge pins? What supposedly gets them up there? Believe what you like, but the string does exert a vertical pushing and pulling (or lesser pushing) force on the bridge.  <blockquote type=cite class=cite cite>Good.&nbsp= ; So, what are your concerns with negative downbearing?</blockquote> Overall downbearing in a conventional design: The soundboard isn't compressed, so there will be an impedance mismatch between the board and string scale (killer octave). The coupling between the bridge is compromised. Not eliminated, but less positive. The piano typically sounds lousy there.  Ron N </html>