[pianotech] CA pinblock with tight bushings?

[David Love]

At some risk of a less than precise explanation it's not an amplifier because no energy is added. The energy from the string is not boosted, it is converted to soundboard energy and the sound that is produced is not an amplification of the sound made by the string, it is new sound and unique sound produced by the soundboard Itself using the energy from the string. The sound is louder than the sound produced by the string (still present btw while the soundboard is doing its thing) not because it is amplified but because the nature of the soundboard having more surface area and more mass moves more air than the string is able to on its own. In conversions like this there is always net energy loss.  While the conversion of string energy to soundboard energy results in a more audible sound that's because the soundboard requires less energy to make a louder sound owing to its physical characteristics when compared to the string. And it's a good thing since the amount of energy that the soundboard ends up with will always be less than the string started out with. That the energy from the string gets converted to soundboard energy should not, however, be confused with amplification. 

There may be a more scientific and precise way to describe it but I'm still working on my degree in kindergarten physics.


David Love
www.davidlovepianos.com
(sent from bb)

-----Original Message-----
From: Bruce Browning <justpianos at gmail.com>
Sender: pianotech-bounces at ptg.org
Date: Thu, 17 Feb 2011 13:22:48 
To: <pianotech at ptg.org>
Reply-To: pianotech at ptg.org
Subject: Re: [pianotech] CA pinblock with tight bushings?

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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