Ron Nossaman wrote: > > > > So given this action by the tuning fork, mounted as it I described, there is > > no piston like up and down motion exerted on the panel as far as I can see. > > Only only a piston like out and in motion exerted alternately on the > > north/south then east/west sides of the hole. > > You dismissed the fork pretty quickly here with one quoted article. Why do you > assume no piston like up and down motion and rule it out up front? What rules > it out? Ron,,, I took the up and down motion out of the picture by not letting it come in contact with the wood. I don't think I could possibly have "argued" anywhere that such up and down motion didn't exist because...well.. because I did exactly the opposite. So its not really a case of me "dismissing" the tuning fork, as it is a matter of deciding on purpose what part of it to allow to come in contact with the wood. What article did I quote ? I did refer you to an animated gif which shows the wave propagation of a tuning fork. > Strike a fork (preferably one with a long straight round or rectangular > handle) and press the tip of the handle against a tabletop perpendicular to the > top and about an inch from the edge. Note the sound produced. Now strike the > fork and press the handle it in the same spot with the fork horizontal to the > tabletop and the tines (over the edge) one above the other. Note the sound. > Strike the fork again and press the handle in the same spot with the tines side > by side. Note the sound. Repeat three or four times to get average sound > differences between these different positions. What did you observe? What does > this tell you, and how do your observations mesh with your conception of how > the fork works? My fork has this little ball on the end, so I had to use the edge of a shelve to get it to sit flat on the sides, though I suppose the results should be comparable. In my case the volume created by the butt end was louder then the results from the sides. Both ways of aligning on the side gave the same loudness but less the the butt end. This fits perfect with this description of the tuning forks function. The only thing new in this is the realization that the energy coming out the end apparently is stronger then the energy coming out the sides, which is neat to know..... Perhaps because there are two waves fronts coming out of the side for every one coming out the bottom ? > Again, I'm not looking for article quotes or doctorate driven canned > sesquipedalian soliloquies explaining little at vast syllabic expenditure, and > so obtuse and convoluted they are bound to be misinterpreted on some level. I > want your own personal mental processing of what you see, tempered against what > you know of very basic high school science level physics. Actually, I think its time we all made a concerted effort to leave High School physics behind as much and as quickly as possible. I purposely avoided quoting the four sources I spent 3 hours reading and re-reading in attempt to gain a good enough understanding of what was being said, so that I could give you exactly this personal mental processing you asked for. The descriptions represent my present understanding of what I have read and thought about. > Stuff most everyone was taught at some time and already knows about. What are > your thoughts, > observations, and explanations of what is physically happening in that fork? > What are the tines doing? What is happening in the body of the fork, including > the handle, that accounts for what the tabletop experiment told you. I described the action of the tines in my last. I suppose I could have gone on to say that the fork can be viewed as a bar which is clamped in the middle with the ends of the bar bent upwards. My table top experiment is incomplete. I have to verify that with an open air mic and a contact mic. And I don't think the forks action was really the point with that one as the significant difference I pointed to was that of the case of listening to the open air sound, vs isolating (as best I could) the sound internal to the wood. As I used the butt end of the fork in all cases in the table top experiment, the basic action and energy should be more or less constant. The difference in volume produced by the countertop seems obviously related to the wood orientation itself, though I will be a bit confused methinks if after putting a contact mic I find that there is very little difference in the amplitude when the fork is placed on the side of the counter vs the top. Why THAT should result in a different relationship then listening open air will require some explanation I don't have at the moment. But I have to verify those results first. > > > > Ok... thats my first shot at it... I await the now er.... acoustumed > > slaughter...hehe. > > > > Richard Brekne > > You're OK, you just skipped over the orientation part. Try the fork test, drink > plenty of fluids, ponder, don't read, and call back when the test results are > in. Grin... will do. But I gots to read... at least in between all that other stuff :) > > Ron N Thanks muchly for this response, and for the suggestion of that fork experiment. What did you mean by skipped over the "orientation part" ? Skål ! -- Richard Brekne RPT, N.P.T.F. Bergen, Norway mailto:rbrekne@broadpark.no http://home.broadpark.no/~rbrekne/ricmain.html
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