Delwin D Fandrich wrote: > > > Don't know what to say, Richard, except that sometimes you can't learn > everything there is to know about a subject off the Internet. And of course, one does not. One uses as many resources as one can. It seems a bit presumptuous to assume anything else. > > Hitting the thing with a hammer is not the best way to develop Chladni > patterns, but it is one way. And, as I said, a rather crude one at that. > Which is not to imply that might not be useful to the folks doing it. Well then... seems like I must have done my homework then, as this is basically what I have been saying all along, though perhaps a bit more exclusively... though to be sure... learn a bit every day as they say. But I still see nothing in this that goes to show that these edge patterns have anything to do Chladni patterns. If they are shown to be part of a resonant mode, then they are. If they are not part of any resonant mode, then they have nothing to do with Chladni patterns. > But, the soundboard is being excited mechanically at the frequency of the > desired mode, in this case the fundamental. > In fact it is being excited at > most of its vibrating modes, at least those consistent with an impact from > a relatively soft and probably fairly massive hammer. The fact that banging the sound board excites all the modes too some degree is not disputed, nor is the fact that judicious use of a hammer can lend more support to a given mode including the fundamental. It just doesn't seem particularly usual to display these (Chladnis) with sand in this fashion and perhaps that is because the resulting patterns are so poorly defined. It does seem usual to use this method of excitation for computer modal analysis as discussed by Wogram. It is not given by any of this that Steingręber is (consciously or otherwise) exciting, viewing, and manipulating the first, or any particular mode at all. If he is, then great. But since he himself says it has nothing to do with these, and since I've seen no reason to doubt him, I'll delay accepting any position to the contrary. > The soundboard, by its nature, will filter out energy at those frequencies it does not respond > resonantly to and will break up -- however briefly -- to those that are > resonant. The strongest of these will be found at the fundamental > resonating mode of the soundboard assembly. > That's not in dispute either. > Del > As far as I can see, the only real moment of contention is that which was from the beginning of this little round. That is, whether or not Steingrębers edge patterns have anything to do with Chladni patterns or not. If they conform to a resonant mode, then they do. If they do not conform to a resonant mode...they they have nothing to do with Chladni. Simple test to find out. Run the fundemental resonant frequency and find out. We're going around in circles here Del. And I am not going pursue any discussion that goes along your opening line here. So until something new comes up, I'll stand where I do now and leave it at that. Cheers RicB -- 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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