Touch weight David Stanwoods comments in reply to my article "Touch weight & Lever Ratios" (see June 2003 Journal) contain a few points I believe should be clarified. First of all is Stanwoods claim that "Brekne's formula is just a different slant on the Equation of Balance". This <<formula>> is BW + FW = ((SW x HR x WR) + WW) x KR, and while I could perhaps be flattered by the thought this could be rightfully attributed to me, it is in reality a straightforward rendering of the simple product of the ratios of three levers and their corresponding weights. It could just as easily have been a textbook example. The method for adding levers thus goes back in time a couple thousand years, which of course means that such very basic methodology is prior knowledge. The Stanwood Balance equation is not more nor less then a simple yet very clever piano specific application of that method. It diverts from it enough to warrant patent protection in itself and that of course should be respected. It is simple in that its derivation is quite basic algebra (as described both by Stanwood in his letter to the editor, and by myself in somewhat more detail at the end of my article). Clever in that does not utilize the individual ratio values for both the whippen and shank at all and because it allows for an easy to understand metrology in addition to very convenient measurement methods and. Stanwood also states that the below quote from my article is "simply not true" "the overall ratio is the same regardless of whether its taken from distance measurements, weight measurements, or speed measurements" I can only say that in the given context this above quote is most certainly true. The fact that differing key dip / blow ratios can be found to exist for the same Strike weight Ratio simply shows that these two are measurements of different relationships. That does not detract from the fact that the Strike weight ratio can be expressed in terms of its corresponding distance ratio. Stanwood himself says as much in a separate article to the Dutch technical journal and indeed, this distinction was a fundamental point to my article. That is not to say that the standard distance ratio is the same as the Strike weight Ratio. These two are different ratios with different effective lever arms. It does say however, that whatever ratio relationship is measured yields consistent results for all three relevant leverage factors by definition. It is however, necessary to be consequent in the application of the appropriate force vectors valid in any given ratio relationship in calculating all corresponding factors. An interesting claim is made tho at the end of his letter, where he states his believe that the "best and most efficient geometry has the highest distance ratio vs. weight ratio" I assume the weight ratio is his own SWRatio, but I am curious to know exactly which distance ratio definition he is operating with here. Also it would be interesting to hear more of the justification for this position. Similiar thinking prompted me to pose a ratio question along these lines just before I went on vacation that David Love responded to in some detail. All this being said I would like to reiterate that for very much work involving reconfiguration of an existing grand piano action, the Stanwood ratio, method and metrology is by far the best set of tools we have so far. I encourage one and all to familiarize themselves with these, and to respect whatever patent restrictions apply whenever and wherever they are appropriate. Richard Brekne, RPT, NPTF -- Richard Brekne RPT, N.P.T.F. UiB, Bergen, Norway mailto:rbrekne@broadpark.no http://home.broadpark.no/~rbrekne/ricmain.html http://www.hf.uib.no/grieg/personer/cv_RB.html
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