Sound waves(The behavior of soundboards)

[John Delacour]

At 10:51 PM -0800 1/13/02, Delwin D Fandrich wrote:

From: "Phillip L Ford" <fordpiano@lycos.com>
>>... - make the agraffe and plate system very stiff here so that 
>>they move as little as possible so that string energy is dissipated 
>>as little as possible at this point.  This would certainly be easy 
>>enough to prove or disprove. Simply put an accelerometer on an 
>>agraffe and strike the string.  If you are correct then the 
>>accelerometer would register zero.  In my opinion, if this were to 
>>happen,it would be in your words 'fantastic'.
>
>Phil, this is precisely what does happen and, yes, it is proven by the
>accelerometer tests you've described. The agraffe does move in response to
>the motion of the string. As does the capo tastro bar. Hence the various
>schemes to couple the capo tastro bar to the pinblock flange.


>Plate flanges also move in response to the vibrating energy in the strings.
>It also is proven by the various accelerometer tests that have been
>conducted over the years. This motion is the basis for the Steinway bell and
>coupling bolt along with the various nosebolt schemes that have been
>developed over the years.

At 12:59 PM -0800 12/17/01, Delwin D Fandrich wrote:
>The accelerometer doesn't care at all about the molecules inside the bridge,
>the bridge pin or the glue line. It measures only the physical acceleration
>and motion of the object it is fastened to.


At 9:31 AM -0800 12/19/01, Delwin D Fandrich wrote:
>Yes. And they are not 'some kind of ripples,' they are the standard wave
>motions of a vibrating edge-supported diaphragm.

At 1:47 AM -0800 12/19/01, Robin Hufford wrote:
>In the interests of  amicable discussion I would have to say however that
>as the members of this list are at least able to operate computers and are,
>evidently, literate, it is not likely  they misconstrue what an 
>accelerometer is
>or what it can do although in point of fact the  motion itself is not what is
>measured but rather the time rate of change of velocity...


I'm afraid, Robin, that likelihood is very real indeed!  It really 
does appear that they think it is measuring bodily movement, 
fantastic though you and I find that.

JD