Sound waves(The behavior of soundboards)

[Delwin D Fandrich]

----- Original Message -----
From: "John Delacour" <JD@Pianomaker.co.uk>
To: <pianotech@ptg.org>
Sent: December 17, 2001 4:05 PM
Subject: Re: Sound waves(The behavior of soundboards)


> At 12:59 PM -0800 12/17/01, Delwin D Fandrich wrote:
>
> >The bridge is physically moving predominately in the
> >vertical direction with some fore and aft motion and even a little side
to
> >side motion thrown in for good measure. Whatever else might be taking
place
> >inside the bridge might be open to some speculation, but the bridge is
> >definately and physically moving.
>
> Del, do I have to repeat for the sixth or seventh time that I have
> never suggested that the bridge does not move?  Please do read my
> messages if you want to contribute anything useful. I simply can't be
> bothered to go back and gather quotes, but only yesterday
>
> At 8:01 PM +0000 12/16/01, John Delacour wrote:
> >Did I ever say the soundboard does not move?  That would indeed be
> >an odd statement. Did I ever say the bridge does not move?  Since
> >the bridge is glued and screwed to a flexing soundboard, that would
> >also have been a pretty tricky position to maintain.  I said neither.
>
>    Neither you nor Ron seem to have any agenda but to keep your minds
> closed and vaunt your own preconceptions, parrying any attempt at
> useful discussion with ridicule or ignorant know-all comments.  I'm
> sick of the pair of you.
>
> JD
>

Sorry, John. When you wrote the following it seemed to me you were trying to
get the bridge to not move:

"Under the bridge,
say the bass bridge, I arrange a massive trestle with thick metal
blocks pressing up against the underside of the bridge line, and on
top of the bridge I place a long lead weight as heavy as I can lift.
And if this isn't enough I borrow hydraulic equipment to make sure
that bridge really can't move.  I haven't tried it, but you suggest
the effect will be to kill the bass of the piano as though the
soundboard and bridge were not there, since the loudspeaker effect of
the soundboard depends on the solenoid effect of the bridge."

I'm not sure what you mean by the 'solenoid effect of the bridge,' but, yes,
I'd say without bridge movement you wouldn't have much piano tone.

Del