I think I took my Z formula from Roberts. It's all calculated from the string data, not from the board. There are a couple of formulas for this particular factor and nobody seems 100% satisfied with how the data output relates to the actual sound produced. Others may be able to contribute more to the formulaic issues. I input the data so long ago now that I've conveniently forgotten the headache I got trying to translate the formula into spread sheet language. David Love www.davidlovepianos.com -----Original Message----- From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of Gene Nelson Sent: Thursday, May 28, 2009 9:14 AM To: pianotech at ptg.org Subject: Re: [pianotech] Modified L Scale with 5 note transition I have read how Del Fandrich describes Z = the square root of springiness multiply by inertia. Inertia should be a simple Newtonian mass measure - do you weigh the board? How do measure springiness - it could only come from the ribs - am I on the right track? How do you get this onto spreadsheet? Gene ----- Original Message ----- From: "Ron Nossaman" <rnossaman at cox.net> To: <pianotech at ptg.org> Sent: Thursday, May 28, 2009 8:57 AM Subject: Re: [pianotech] Modified L Scale with 5 note transition David Love wrote: > Speaking of modifying scales. Don't know how much of this will come > through but here's an example of a modified L scale with a 5 note > transition bridge that I'm playing with. You can see the shape of the > bridge by the purple line showing the speaking lengths, the five note > transition is seen where the drop in inharmonicity is. The goal is > balancing tension (red), impedance (grey) and inharmonicity. The blue > line at the bottom indicates break point %. Here's what my last one looked like. Ron N
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