NEWS FLASH! "Conover clobbers Steinway !"

[Ric Brekne]

This is a multi-part message in MIME format.

---------------------- multipart/alternative attachment
Mike and Terry

Mike stated...

    "Wogram states clearly in the excerpts you provided, that the ribs
    are there to equalize the stiffness of the board across and parallel
    to the grain, to optimise the diaphragmatic response."

Actually Wogram  did not mention anything about optimising the 
diaphragmatic response. He said

    "If this anisotropism is not compensated for by the addition of ribs
    running across the grain, the effective vibrating area is reduced
    and the radiation efficiency is decreased over a broad frequency band."

And why would that be ?  I think we can agree that if anisotropism is 
fully compensated for, then the speed of sound through both directions 
is going to be quite equalized. And that if there is a significant 
difference in the speed with which sound propagates through the two 
directions in the panel then anisotropism is not compensated for.  This 
follows from the basic formula for the velocity of sound through a 
solid.  /v/ = root (Youngs Moduli */* density).  Density being equal in 
both cases, if Y is the same... (ie bending stiffness is equal) then /v/ 
is the same.  And if /v /is different then Y must also be different 
(since density remains the same in both cases).

Now you can choose to simply relegate the speed of sound through wood as 
a by-product of all this if you want I suppose.  But I submit that it is 
precisely this speed of sound which is the objective of equalizing 
bending stiffness to begin with.  And that by doing so you in effect 
exploit the vibrational area of the board in both directions in as equal 
a fashion as possible.  Which to me at any rate put Wograms actual quote 
into a very senseable light.  

I am more then willing to hear why this reasoning is flawed mind you :)

Cheers
RicB

---------------------- multipart/alternative attachment
An HTML attachment was scrubbed...
URL: https://www.moypiano.com/ptg/pianotech.php/attachments/2f/ad/f2/2c/attachment.htm

---------------------- multipart/alternative attachment--