Hi Robin. I have run into the bridge configuration you mention below a few times a number of years ago, not that I gave it any thought at the time. I was then too busy learning the basics of tuning and regulation. As it relates to the moving bridge idea, I am not really sure you are going to get so far with your line of reasoning, though I certainly see where you are coming from. Those who view the sound board as primarily a diaphragm functioning similar to a loudspeaker probably see, to put a point on it, something akin to a woofer pumping back and forth at the air. For them it is not just the exact point under any given string that is pulling at the sound board. The string would be pulling / pushing at the bridge and the bridge then would want to move in relation to that input along the whole length of it they would reply methinks. >From my other post you probably have picked up on the point that I have concluded that the "ripple" thing has some merit. I think if you read that you will understand what I mean. Its not the ripples themselves that's a big problem between the two camps here, its more what causes them methinks. Also there is a good deal of talking past each other, using different terms to mean different things and a tendency to hold to tightly onto long held visualizations about how things function. Its hard to avoid all that I suppose. In any case I think I will avoid terming those holding to the diaphragm view as "Ripple Theorists" as it seems pretty clear that sound board ripples do indeed push the air and result in the sound that we hear. How those ripples get there in the first place is another thing. As I see it, the major point of argument is what kind of wave movement is going on at the point of energy transfer from the strings to the bridge / sound board assembly. Then how that energy can be dispersed through the assembly resulting in these sound producing surface ripples. But we are never going to resolve any of that satisfactorily until all parties are familiar enough with wave mechanics to avoid some of the misconceptions about things like these so called "ripples", how compression waves actually function, relying to heavily on 2 dimensional thinking... and misconceptions about how a sound board is supposed to move (physically) first and in turn move the bridge, which was an unfortunate illustration that I think JD made in attempt to describe wave movement. As I said in my last "Sound waves" post... it seems to me that the waves propagation through the board IS sound board movement and describes that movement perfectly. And we certainly are not going to get anywhere unless all are willing to accept present physics definitions as the basis for communication. That much at least we need to leave to real world physicists. In a way I think I see the point held in this respect by the diaphragm camp. Again... drop that stone into the pool, you see instant motion at the point of contact, and the surface ripple moving outwards. That fits nice (as far as it goes) with the clothesline analogy, and if you are stuck on this point I can certainly see the difficulty in letting go of it... especially with that woofer visualization in mind. But a few hours glancing at relevant physics texts shows quite clearly that there is more to it then that. Like for example this issue of longitudinal wave input driving a sound board resulting in said emanating sound. The whole discussion has caused me to look through and hunt down and read and try and grasp.... and what is primary to that process doing me any good is a concious gapping wide open admission to myself that I really don't know jack diddly to begin with....ergo the reason for reading, the reason for learning. If I was to just open up my books and look for evidence to simply support one view or the other I would be wasting my time as far as learning goes. Do you have any pictures of that Chickering ? Might be nice to take a look eh ? My best -- Richard Brekne RPT, N.P.T.F. Bergen, Norway mailto:rbrekne@broadpark.no
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