Sound waves(The behavior of soundboards)

[Ron Nossaman]

> From this immobile centre of inertia will radiate periodic 
>compressions of the particles.  If the shank of the fork is held 
>loose, a small amount of this energy will be transmitted into the 
>fluid of the fingers but most of it will be reflected internally. 
>Particles all round the surface of the shank will be "dancing" in and 
>out with minuscule amplitude of oscillation but with great force, so 
>that unless the fork is held firmly in contact with the resonant 
>system (e.g. the table) the momentum of these molecules will be 
>sufficient to push the whole fork away.  This is not because the fork 
>is moving up and down (or sideways) but because the particles at the 
>surface are oscillating.  It makes very little difference to the 
>amplitude of the transmitted sound whether you press the fork 
>vertically against the table or flank-wise parallel to the table.
>
>JD

John,
I explained my reasoning. Do the tines vibrate without bending? I have a
fork here with about 100mm length tines. The tine tip excursion looks to be
around 2mm. I can see it. How is this possible without the tines bending?
If the tines bend, the overall length changes... etc. As I explained. I say
the tines have to bend for the fork to work. Of course the center of mass
between the tines will remain very close to stationary if the fork is
balanced. I mentioned that talking to Richard B, explaining the difference
between the handle movement at the tip, and that on the side. I've already
addressed this with conventional physics. In the context of Rayleigh's
description, that side to side motion is what he is addressing. He doesn't
mention anything at all about either movement or vibration in the handle,
much less stress induced pressure waves. Nothing Rayleigh said here even
remotely hints at, let alone supports your claim. Nor does it negate mine,
that I can see. It looks, in fact, to have nothing to do with either
viewpoint of what moves the tuning fork handle. Again, can either you or
Robin produce an actual straightforward verifiable principal of physics
that will account for your stress transduced pressure waves? Also, If you
try the test you mention above, you will find that it does indeed make a
considerable difference in sound whether you press the handle tip, or the
side, against a tabletop. Saying it isn't so doesn't make it not happen -
even saying it isn't so repeatedly.

Ron N