Danny, The key is impedance, as you note. I'm not sure I've ever heard a console that didn't have room for tonal (or almost any other) improvement. One of the seminal studies on this kind of thing had nothing to do with pianos (surprise), but dealt with the vibration of steel plates in manufacturing applications. In that study, rather than add external mass, the thickness of the plates was varied... I'm not a physicist, either, but extrapolate that, if we consider the board/ribs/case/superstructure as a dynamic unit, then changes that we make in/to individual components will change (however miniscually) the entire structure. In view of the range and domain of variables in the structure of even a single, given piano, the improvements and/or degradations of performance probably have as much to do with the experience of the technician doing the work as to pure reductive analysis. More later, perhaps. Best. Horace Horace Greeley Systems Analyst/Engineer Controller's Office Stanford University email: hgreeley@leland.stanford.edu voice mail: 650.725.9062 fax: 650.725.8014
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