Sound waves(The behavior of soundboards)

[Robin Hufford]

Ron N, Del,  and others,

     Isn't it easy to see in the events described below that the process whereby
the glass, although acquiring sufficient energy to subsequently shatter, is
acquiring energy from the sound pressure incident upon it and that this  is
molecular and does not require "physical, substantial, motion" to occur?   How
difficult is this to see?   Were one holding the glass at the stem one would
feel nothing, no sense of motion as the glass, through resonance, acquired this
energy - it would simply burst in one's hand.  It is obvious that a
soundboard/bridge is markedly more flexible than a glass: but the comparison
still holds utility for analysis of the mechanism of energy transfer.  Sure,
there is some kind of motion but it is essentially molecular.
     Should you impose a coordinate frame to get a grasp on the glass's position
in space its coordinates would be unchanged until fracture, although I do
believe one is likely, at some point, to sense vibration in the glass.  The
point is that the accumulating energy in the glass is obviously the result of
energy transfer on a molecular level, or now are you going to argue that the
glass itself  moves in a manner similar to that  you assert occur at the
soundboard/string interface which, by the way, appears to progressively
decreasing in these discussions?
 If the answer is yes, that what would anyone you suppose to be the magnitude of
such motion?  Please don't offer observations  that there is mass hence
acceleration, or that the air is not a string, or that the glass is not a
bridge, or that a tuning fork is not a string.  It is an analysis of the process
of energy transfer itself that is the question at hand
Ron Nossaman wrote:

> >>When these compression waves supposedly travel down through the bridge to
> >>the soundboard, moving the board before the bridge moves, how does this
> >>manage to happen with the board attached to the bridge at exactly the spot
> >>that these waves are supposed to move the board? I'd love to know the
> >>mechanics behind this.
> >
> >For the same reason that the wine glass does not shatter the moment
> >the lady sings the top C but a moment afterwards.  The glass is
> >unaffected while the wave is travelling towards it.  Surely this is
> >obvious.
> >
> >JD
>
> Hardly the same thing, as is surely at least as obvious. This still leaves
> the perpetually unanswered question of how minute a bridge movement is no
> movement at all. I had presumed that your post immediately following this
> one would clear that up for me and put this increasingly tedious exercise
> to rest, but it hasn't happened. I would like an answer to this please,
> since it is the basis of your stand in this discussion.
>
> Ron N