Hey, Alan & Ric, I believe Ric is asking about the inharmonicity constant. I don¹t know if that is the name used by engineers, but that¹s what I have heard it called. It relates length, diameter, and tension to predict the inharmonicity of a particular string/note. PScale used it to generate an inharmonicity number for each note, and ETDs use it to build their stretch curves. I have only seen one value referring to music wire in general, and I have wondered whether it might be different for Mapes vs Roslau. I would certainly expect Pure Sound to be different. I can¹t lay my hands on a precise value, though. Ron? Del? I¹m getting in over my head here! Bail me out! Regards, Ken Z. On 1/8/07 3:06 PM, "RicB" <ricb at pianostemmer.no> wrote: > Thanks Alan... I was beginning to think I wasnt going to get any response on > this at all. No, its not the Young modulus I'm after. I just need to know > how to find this constant <<K>> which keeps coming up in formulas about > inharmonicity and string stiffness. I also need to know if it changes along > with the type of string material used. > > Specifically... in both Nossamans and Overs spreadsheets for scaling there is > a formula for figuring out string stiffness in which a constant is used... and > I have no idea where this constant comes from or what its actual meaning is... > and hence have no idea if it remains the same for Pure Sound wire as compared > to Rosslau for example. > > On the side.... I also am working on using the scale tensions that result from > any given design to determine a basic downbearing picture for given string > offsets and building that into the spreadsheet. I already have that math in > place.... so the addition of one more specs column (for string offsets) and a > couple calculation columns will yield downbearing in Kg for each unison... and > a graph that shows how the scales downbearing looks over the entire > soundboard.... Thought that might be handy :) > > Cheers, and thanks for reminding me of the Roberts source... I dont have his > book... but There are those articles in the journal. > > RicB >> >> Hey Ric, >> >> Are you referring to Young's Modulus (Y)? Have you checked out The >> Calculating Technician by Dave Roberts? I think there is info in his book >> that might be useful. >> >> Alan >> >> >> -- Alan McCoy, RPT >> Eastern Washington University >> amccoy at mail.ewu.edu >> 509-359-4627 > -- Ken Zahringer, RPT Piano Technician MU School of Music 297 Fine Arts 882-1202 cell 489-7529 -------------- next part -------------- An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/caut.php/attachments/20070108/46db4822/attachment.html
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