Hi Joe The two variants I'm looking at were calculated by two different scalers, both taking into account for Pure Sound density.... but using unfamiliar formulas for scaling programs. The one is just a program that is no longer available (the one that uses the Harmonicity parameter), and the other by a fellow recommended by Pure Sound. I'm putting the numbers in the spreadsheet type that comes down from the Calculating Technician. Reading both the articles and the accompanying documentation, there is no explanation as to where this figure is to go into the formula, or how it is to be translated to whatever measuring units are to be used. Take the Tension formula for example... in the T= ( fLd / K)^2 * (1+ A(D^2/d^2)-1). A is the value for wrap (no explanation given anywhere I can find as to how this is ascertained or what exactly it represents in terms of measuring units.... its just a number given) K is even less clear... it is defined as just a constant with no reference at all to what it stands for, let alone how to ascertain it. One is tempted without further ado to conclude that K is the mass coeficient... but how does one make sure its in the right units ? Taking the other form for T Rhodes gives in his execution of Roberts formulas you have T = 2(m/6)^2 *(Ld / 7.69)^2 * (1+A(D^2/d^2) -1) Here K is necessarilly manipulated so as to facilitate a different way of dealing with the frequency parameter... and its corresponding number is 7.69 Again no explanation is given so I dont know whether or not this is average density of the wire. And if it is... well then Juan gives 7.85... not 7.69 So... if you know just where the average density parameter figures into this and the other formulas given by Roberts in the Calculating Technician... I'd realllllly like to know :) Cheers RicB This formula is based on modern piano wire, average density 7,85. These data are all hidden within the number: 2514. For Pure Sound wire this number is : 2530. (average density: 7,90) For Malcolm Rose's wire the number is : 2488. (average density: 7,769)" Ric, I read through all of that and finally got to the 2nd from the bottom line- - -Voila': it reads average density 7.90!! That's the mass coefficient and has to be plugged into the scaling formula to get a better picture of what that stuff is all about and how it will react in regards to tension and Inharmonicity and Impedance! If you didn't do that then whatever you are planning on this piano needs to be re-calced, IMO.<G> :-( Best Regards, Joe Garrett, R.P.T. Captain of the Tool Police Squares R I
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