Sound waves(The behavior of soundboards)

[Delwin D Fandrich]

----- Original Message -----
From: "Ron Nossaman" <RNossaman@KSCABLE.com>
To: <pianotech@ptg.org>
Sent: December 21, 2001 4:06 PM
Subject: Re: Sound waves(The behavior of soundboards)


>
> Oh, sorry. Since you only asked that once in passing, I mistook it for
just
> another diversion and didn't give it much weight. As far as I know, there
> isn't one. You see, the strings moving the bridge is my own theory,
dreamed
> up by me, based on sound mechanical and physics principles, so it isn't
> likely to be on a university web site anywhere. Oddly enough though, two
> piano designers, builders, and fellow rebuilders who have against all
> apparent odds actually given it some thought, seem to hold similar views.
> Imagine such a thing!

... At least one of whom came by it independently, having studied both the
real-world motions of a variety of soundboards and bridges (attached to both
soundboards and psuedo-soundboards) and the computer-modeled motions of
soundboards.

My conclusion, after all of this, is that vibrating strings--regardless of
what is happening at the molecular level--physically move the bridge they
are attached to. If the bridge is physically attached to a soundboard, then
that soundboard moves in concert with the motion of the bridge. If the
bridge is not attached to a soundboard, but to something like a set of force
transducers, there is still a transfer of vibrating energy due to the
physical movement of the bridge caused by vibrating strings attached to it.
(My reason for introducing the idea of Baldwin's Electo-SD-6--or whatever it
was called.)



(John wrote:)
>
> >No one is claiming that there is no disturbance or stress at the
> >meeting of the string with the bridge, otherwise no sound would be
> >transmitted, but to claim that this disturbance results in the bodily
> >movement of the bridge and drives the soundboard as a solenoid drives
> >a loudspeaker is nonsense.

Solenoids are cylindrical coils of wire surrounding a moveable iron core
that moves along the length of the coil when an electric current is passed
through it. Solenoids are used as switches and relays, for example, in a
motor vehicle to complete the circuit between the battery and starter motor.
Loudspeaker voice coils, while similar, are not the same thing at all.

But then, I gave the analogy of the loudspeaker, not as exact description of
soundboard function, but as an analogy.

Del