Hello Ric Interesting post - and one which affects all who undertake the restringing of pianos. In order to comply with the best proceedures with relation to bringing a piano down to remove the old strings - and, more importantly??, bringing the piano back to A=440 what, in the interests of your post, do you believe to be the best course of attack? Please take it step-by-step if you would be so kindly! So you're face with restringing an S&S model D........go from there! Regards Michael G (UK) ----- Original Message ----- From: "Richard Brekne" <Richard.Brekne@grieg.uib.no> To: "Newtonburg" <pianotech@ptg.org> Sent: Saturday, February 12, 2005 12:54 AM Subject: re: Killer Octave & Pitch Raise > Udo Steingręber and I got into a conversation about this in Helsinki a > couple years back on the only opportunity I've had to sit and chat with > him. It was part of a discussion where he was explaining why he felt > compression soundboards were the way to go. He mentioned something about > the so called K point (I think this is a Klaus Fenner coined term), which > as I understood it was that point on the soundboard where crown from both > along the grain and cross the grain intersect and is at its highest point. > This area is exactly (and always) in the area typically refered to by > american techs as the <<killer octave>> area, and of course varies > somewhat from piano to piano. It is then also the exact point then that > is most vunerable to failures. Udo was of the position that along the > grain crowning was every bit as important as cross grain crown. Something > to do with along the grain compression due to downbearing having a > stablizing effect on cross grain crown and strength. He also meant that > both these were needed to produce the kind of acoustical results he wanted > from a soundboard. > I'm under the impression, correct me if I am wrong, that most of the rib > crowned methods extoled on this list do not employ any purposefull along > the grain crowning as part of how the panels are attached to the rim, and > therefor do not have this vunerablity. It would stand to reason that they > too are not able to create the same acoustical results.... (whether that > is preferable or not is an entirely different subject). > > Disclaimer. This description is my understanding of what Udo was saying, > tho I beleive it is pretty accurate. Not being a soundboard engineer tho, > I'll leave it to more experienced to explain, interpret, or whathave you > the above. > One other thing tho... I've always heard that large changes in pitch, and > destringing / restringing proceedures should be carefull of this area.... > making carefull changes that are appliled very evenly, exactly because > this area can easily be damaged by sudden large changes in the stresses > applied to the panel as a whole. Seems to jive well if the basic view > above is correct to begin with. > > Cheers > RicB > > > > >
This PTG archive page provided courtesy of Moy Piano Service, LLC