Despite all the gobbledy-gook that you point out, Bluthner's approach seems to be pretty much in line with Del and others' advocacy of rib-crowned soundboards (I think). I took "cylindrical curvature" to mean that the sheet is curved along the diagonal-ish line of the ribs, but flat as measured across the ribs. I don't know if "curve tension" is supposed to actually mean anything or not -- I guess if the soundboard is always wanting to go flat but for the shape of the ribs, there would be some tension there. I definitely agree with you that adapting the bridge to tension makes no sense. About the "red beech inner rim [being] preformed to the correct angle to ... retain SB's curve tension," I'm not sure I'm clear on the layout of things. I sort of thought it meant that the surface where the soundboard mates with the rim is ground or whatever so that it mates perfectly with the edges of the soundboard in its cylindrically curved shape, so basically there is no tension around the perimeter. It does seem like maybe that would be insignificant compared to the ribs' shape-holding role, but at least it doesn't work against it. If the surface of the rim were curved into the same curve as the curve along the length of the ribs, not just "angled" where the "ends" of the curve fit in, wouldn't that be pretty significant for holding the shape, though? The Kawaii claims were indeed crazy -- or rather calculated advertising mumbo-jumbo. Regards, Trent Lesher -----Original Message----- From: Farrell [mailto:mfarrel2@tampabay.rr.com] Sent: Wed 1/28/2004 4:39 AM To: Pianotech Cc: Subject: Re: Permanent Soundboard Crown! Hey Ric, maybe you'll enjoy this one more - it goes even further - from the Bluthner web site: At the beginning of piano making the soundboard consisted solely of a thin wooden board, stiffened with bars glued on the underside and the bridges on the upper side. Further development was derived from the soundboard of a violin with its spherical crown. However the soundboard of a violin is made of a thick piece of wood being shaped by grinding, chipping and sanding into its final form. A piano soundboard is made from a thin board being bend by force into this form. This method however produces disadvantages comparable to those which one will experience when you try to put a sheet of paper atop a ball. 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. Ok, new terms now. "Curve tension" - any engineers out there? Look that up in your old Engineering 101 book. Cylindrical curvature? The top of their inner rim in not more-or-less planar (and the few that put a slight rise in the concave curved side doesn't count)? And somehow the angled inner rim retains the soundboard's curve tension! Also, how does one go about adapting a bridge to tension and curvature? The curvature I can roll with, but the tension? Who/what is pulling where? Or maybe they are just pulling our leg? Fun thoughts. Terry Farrell ----- Original Message ----- From: "Richard Brekne" <Richard.Brekne@grieg.uib.no <mailto:Richard.Brekne@grieg.uib.no> > To: "Pianotech" <pianotech@ptg.org <mailto:pianotech@ptg.org> > Sent: Wednesday, January 28, 2004 1:53 AM Subject: Re: Permanent Soundboard Crown! > Grin... > > Funny how we keep running into this from so many places isnt it ? You > simply have to wonder :) > > Cheers > RicB > > Farrell wrote: > > > From the Kawai US web site - enjoy! > > > > *The Drying/Re-Moisturizing Process.* Kawai employs an inventive > > method to create a permanent soundboard crown. SNIP ****** IMPORTANT NOTICE ****** This e-mail, and any attachments hereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail, you are hereby notified that any dissemination, distribution or copying of this e-mail, and any attachments hereto, is strictly prohibited. If you have received this e-mail in error, please immediately notify me at (312) 207-1000 and permanently delete the original and any copy of any e-mail and any printout thereof.
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