This is a multi-part message in MIME format. ---------------------- multipart/alternative attachment ----- Original Message -----=20 From: Farrell=20 To: Pianotech=20 Sent: Wednesday, January 28, 2004 12:39 PM Subject: Re: Permanent Soundboard Crown! Studies made by Bluthner research and development department have = proven that tensions and compressions develop on the edges that are = inhomogeneous and not controllable. In contrast, the soundboard that = Bluthner has developed has a cylindrical curvature so that the tension = of the soundboard can be exactly defined. The ribs are planed to fit the = curvature needed and therefore the tension of the soundboard remains = intact over the decades. In fact, even under difficult climatic = conditions the curvature will remain in a constant form since not only = the rib structure will hold it in place but also the red beech inner rim = is preformed to the correct angle to receive and retain the soundboard's = curve tension. Because the soundboard is pre-stressed in this fashion it = can be fitted exactly and remain under curve tension permanently. The = bridge, of course, is adapted to the tension and curvature of the = soundboard in its optimum position. This ensures that string vibrations = in their full spectrum are transferred to the soundboard. By utilizing = the resonating surface, the special design of the Bluthner soundboard = generates tone significantly better.=20 The way I understand the above text, Bluethner uses crowned ribs and = doesn't rely (at least not much) on panel compression to achieve crown.=20 They want a cylindrical crown, as opposed to the spherical crown = advocated by piano designers such as Klaus Fenner, who wants the board = to be curved not only along the ribs, but also (roughly) along the = bridge, with a high point at a certain location. Fenner favours = compression-crowning and has some theories about stresses that need to = exist not only in the soundboard, but also in the rim etc. to get a good = sound. I've read both Klaus Fenner's and Ingbert Bluethner-Haessler's books on = piano construction, that's how I learned about the differences.=20 The text posted by Terry F. is pretty confusing when taken alone - = probably because it is translated from German ;-) Calin Tantareanu ---------------------------------------------------- http://calintantareanu.tripod.com ---------------------------------------------------- ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/a2/77/fe/fa/attachment.htm ---------------------- multipart/alternative attachment--
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