[pianotech] CA pinblock with tight bushings?

[Bruce Browning]

Terry, I have heard this argument before, and still tend to disagree with
you on this.
I believe this to be a mechanical amplifier system, just like the old type
phonograph, moving something in a large action, when stimulated by a small
action.
Other mechanical amplifiers exist, eg. hydraulic systems, levers, and this
should not be excluded from the category of amplifier. In fact the
definition of a transducer is slightly incorrect, as, in the case of a
soundboard, the amplification is purely physical motion ie. small movement
of string to large movement of soundboard. The effect on the air movement
(giving your definition of a transducer) is a follow on. In a vacuum the
soundboard would still move, with no consequential sound.
Just thinking out loud here, but maybe we could see the soundboard in
isolation as a transducer between the mechanical motion and the air, but the
soundboard system, incorporating the bridge and strings is definitely an
amplifier.



On 17 February 2011 08:06, Terry Farrell <mfarrel2 at tampabay.rr.com> wrote:

> No, not pulling your leg here Doug. This has been the subject of a number
> of threads on this forum. The soundboard is a transducer. All the energy
> that (does indeed) move the soundboard comes from the vibrating strings.
> There is no energy added to the system beyond what the strings are able to
> provide. An amplifier is a device that uses an addition of power (most
> commonly electricity - such as with a powered speaker) to increase the
> motion of something and thus increase volume.
>
> The reason you don't hear the vibrating piano string very much without the
> soundboard is that the surface area of the string is very small and simply
> cannot move much air. When the string is coupled to the soundboard via the
> bridge, the string moves the soundboard which has quite a lot of area, and
> thus the volume is louder than the string by itself. However, it can only be
> as loud as the string has energy and the soundboard is efficient - no energy
> is added to the system. And thus the soundboard is a transducer.
>
> A transducer is a device that convert one form of energy into another. In
> the case of the piano, the soundboard/bridge assembly converts the motion
> energy of the metal strings into sound energy. Nothing is amplified.
>
>
regards
-- 
Bruce Browning
The Piano Tuner
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