Sound waves(The behavior of soundboards)

[Richard Brekne]

John Delacour wrote:

> AAt 7:09 PM -0800 12/3/01, Delwin D Fandrich wrote:
> >Is this a serious question?....There was still some sound there, but
> >it was muted
> >and thin.
> >
> >...The bridge movement moves the soundboard causing it to vibrate
> >much like the
> >diaphragm vibrates in the loudspeaker.
>
> At 7:25 PM -0600 12/3/01, Ron Nossaman wrote:
> >  > 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.
> >
> >That should be the case. Just like clamping the driving coil of a speaker
> >cone to the magnet. The transducer can't transduce if it can't move.
>
> So way back then you said it "should be the case", according to your
> theories that immobilizing the bridge should prevent any vibrations
> reaching the soundboard, and Del states categorically that the bridge
> moves and acts as a speaker solenoid BUT that there was a muted and
> thin sound.  I have never suggested that the immobilizing of the
> bridge will have NO effect on the sound.  My point has always been
> that a good deal more sound will be audible when the bridge is
> immobilized than would be heard from the string and bridge alone,
> that this sound is emitted from the soundboard and has reached it NOT
> as a result of the "solenoid effect".  If the solenoid of a speaker
> is jammed, no sound at all will be emitted from the cone.  The two
> cases are completely different.
>

Touche'. In otherwords.... the diaphram analogy is far from adequate to fully
describe all of the sound producing elements of the soundboard ??.






--
Richard Brekne
RPT, N.P.T.F.
Bergen, Norway
mailto:rbrekne@broadpark.no