<html> <body> At 09:29 AM 4/8/2004 -0500, Ron wrote, in response to Fred Sturm: <blockquote type=cite class=cite cite><blockquote type=cite class=cite cite>I wonder what basis there is for our notion that bridge tops should ideally be flat.</blockquote> Fred, From a practical engineering standpoint, the flat top is a balance or compromise between termination quality and durability. Presuming positive front bearing (angle between bridge top and speaking length), it gives a more defined and positive termination point at the edge than a top that is curved to be tangent to the string plane, while being less easily crushable (and cheaper to build) than a top that is grooved or "V'd" down the center. <blockquote type=cite class=cite cite>In fact, maybe a mild curvature would be better theoretically, both for transfer of energy and for durability. Possible, I'm not saying it's so.</blockquote> I don't think so. It's that mild curve in existing bridge caps, with loose pins, that makes the false beats we love so much to hear in the treble third of the scale.</blockquote> What about a mild curve WITHOUT loose pins?  I don't think there has been any determination that a curve in the bridge surface has, in itself, anything to do with false beats OR other termination distortion.  It simply has to be taken into account when measuring and discussing downbearing. <blockquote type=cite class=cite cite><blockquote type=cite class=cite cite>   How is load transferred through bridge to board?</blockquote> The string moves the bridge, and the bridge moves the board, which moves the strings, which move the board, etc. - until the string energy is absorbed in the internal friction of the system and dissipates as heat. A piano is, after all, a low efficiency space heater.</blockquote> Is that what you meant, Fred?  You asked about the load, not the vibrational energy?  I'm not sure why you would want to, or if you meant to steer back into that snake pit.  I don't recall that debate being concluded with anything other than an armistice, so Ron's portrayal of the sequence of energy transfer, even if correct, must stand as his opinion. There are others. David Skolnik</body> </html>