Ric, the soundboard does not have a sustain like the string, it must be driven by the string permanently. The out-of-plane connetcion of the string to the soundboard and the driving of the board by the string does not result in a serious longitudinal compression/decompression vibration in the plane of the soundboard in my opinion, (what could be called a real longitudinal vibration), just a transversal wave travelling radial away from the excitation point in the plane of the board, what makes it "appear" a longitudinal movement because of its wavespeed. So in my opinion there is no remarkable longitudinal vibration present in the board that could affect anything. regards, Bernhard ----- Original Message ----- From: "Ric Brekne" <ricbrek@broadpark.no> To: <pianotech@ptg.org> Sent: Friday, February 17, 2006 11:13 AM Subject: Soundboard Animations > Hi Bernhard. > > That was exactly the end consensus of the discussion here on Pianotech a > couple years back. The debate was reallllly heated at times... grin... > for the usual reasons. In the end I even contacted piano friend and > physics/acoustics Dr Askenfelt who agreed... > > Personaly I still cant quite get past the idea that despite the fact > that longitundinal waves do not couple with the air.... their developement > is (should be in my mind) intregrally a part of the overall wave > development of the panel... ie... that what affects the longitudinal must > also affect the rest. > > Never could get a good answer to that, mostly because there was so much > heat that it was difficult to keep the discussion even close to topical. > > I'd love to take that up again however... as there strikes me as much that > is misunderstood.... but ..... well the last one got pretty ugly.... > > Put up more animations tho... please !! > > Cheers > RicB > > Hi Ric, > > Will do my best to set up more animations. > > I think the travelling transversal waves are often misinterpreted as > longitudinal movements > because of their travelling direction in the longitudinal direction with a > wavespeed usually denoted as "c". > The real longitudinal waves in the wood play the same minor or even > negligible role in the soundboard > as the rotational vibrations in the strings in my opinion, because they > have > no coupling to the air. > (not in the strings,.where they can cause serious ringing). > > regards, > > Bernhard > > _______________________________________________ > Pianotech list info: https://www.moypiano.com/resources/#archives
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