This is a multi-part message in MIME format. ---------------------- multipart/alternative attachment David Love wrote: Del: Is there an ideal dimension (height, width and width at the footprint) = in the treble section of the piano? It seems that the two requirements = are at odds, one of flexibility to allow the soundboard to move, and one = of stiffness to increase impedance in that section and improve sustain.=20 Wouldn't it be better to support the board in that section with an = additional rib, say, and leave the bridge more flexible? Or is it six of = one... ---------- It depends, I suppose, on what you mean by 'ideal.' Why do you think the = bridge needs to be "[flexible] enough to allow the soundboard to = move...?" The soundboard is going to move anyway--even if the bridges = were infinitly stiff it (the assembly) would still move.=20 The bridges need to be stiff enough so that the impedance level does not = drop enough to significantly affect power and sustain in between the = ribs. Obviously, if the ribs are closer together, i.e., a greater number = of ribs, the bridge do not have to be as tall to accomplish this. Both = the bridge dimensions and the number of ribs and their dimensions are a = balancing act. The more ribs--and the more stiffness and mass in the rib = field--the lower and less massive the bridge can (should) be. If the rib = field is skimpy the bridges are going to have to be taller and wider to = compensate.=20 Bridge width is usually as much a function of mechanical necessity as of = acoustics. It must be wide enough to easily accomodate the bridge = pinning configuration without coming apart. It has been my observation = over the years that bridges that are much less than 30 to 32 mm in width = are somewhat more prone to splitting. Del Delwin D Fandrich Piano Designer & Builder Hoquiam, Washington 98550 USA 360.532-2563 360.532-6688 pianobuilders@olynet.com ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/be/94/2d/92/attachment.htm ---------------------- multipart/alternative attachment--
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