Delwin D Fandrich wrote: > > > The structural arch works by virtue of being made of a non-compressible > material such as stone, concrete, etc. It is buttressed by an immovable > support on either end. When loaded, it supports the load because of the > non-compressible nature of the arch. Hmm... this doesnt ring entirely true. Its more like a compressible arch can get de'arched to be sure... but only if there is enough pressure or pressure over time to do the job. Its not like we have absolutes this and that. Its a question of degrees... and as somebody (I wont get into who... grin) pointed out a couple years back in another soundboard discussion, with something about a mosquito colliding with a Concord.... relative to what deflects what.... every little bit counts... > The soundboard panel is made of wood > which is far from non-compressible. Even longitudinally. M&H makes much of > their little demo showing how their spider is supposed to support crown. > What they don't mention is that it takes only light finger pressure to > flatten the piece out. Nor do they mention that if they leave the piece in > place for any period of time, say a month or two, the crown disappears. > Wood, at least given the crown radii typical to the piano, is not rigid > enough to function as a structural arch. > Yet the question remains... would the finger pressure needed to flatten the board be less without the web... or would the time required to loose the crown be shorter ? If these answer in the affirmative... then the spider does offer some limited "assistance" in supporting crown. SWAT... there went another bug...:) > Not specifically. You might check the Five Lectures. Richard Brekne has > given the web site addresse several times on the list. A general (though > somewhat elementary) text is the "Fundamentals of Musical Acoustics by > Arthur H Benade, Oxford University Press, 1976. This is available from > Amazon.com. As is "The Physics of Musical Instruments" by Neville H > Fletcher & Thomas D Rossing, Springer-Verlog, 1991. > > Del > One more time Folks..... and the Benade book is a good one to start with as its a bit easier reading. Sarah, ... get the Fletcher :) http://www.speech.kth.se/music/5_lectures/ Brought to you online by the Swedish PTA and in particular Østen Hæggmark -- 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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