Soundboard Animations

[b98tu@t-online.de]

Ric,
the soundboard does not have a sustain like the string, it must be driven by 
the string permanently.
The out-of-plane connetcion of the string to the soundboard and the driving 
of the board by the string does not result in a serious longitudinal 
compression/decompression vibration in the plane of the soundboard in my 
opinion, (what could be called a real longitudinal vibration), just a 
transversal wave travelling radial away from the excitation point in the 
plane of the board, what makes it "appear" a longitudinal movement because 
of its wavespeed. So in my opinion there is no remarkable longitudinal 
vibration present in the board that could affect anything.
regards,

Bernhard


----- Original Message ----- 
From: "Ric Brekne" <ricbrek@broadpark.no>
To: <pianotech@ptg.org>
Sent: Friday, February 17, 2006 11:13 AM
Subject: Soundboard Animations


> Hi Bernhard.
>
> That was exactly the end consensus of the discussion here on Pianotech a 
> couple years back.  The debate was reallllly heated at times... grin... 
> for the usual reasons.  In the end I even contacted piano friend and 
> physics/acoustics Dr Askenfelt who agreed...
>
> Personaly I still cant  quite get past the idea that  despite the fact 
> that longitundinal waves do not couple with the air.... their developement 
> is  (should be in my mind) intregrally a part of the overall wave 
> development of the panel... ie... that what affects the longitudinal must 
> also affect the rest.
>
> Never could get a good answer to that, mostly because there was so much 
> heat that it was difficult to keep the discussion even close to topical.
>
> I'd love to take that up again however... as there strikes me as much that 
> is misunderstood.... but  ..... well the last one got pretty ugly....
>
> Put up more animations tho... please !!
>
> Cheers
> RicB
>
> Hi Ric,
>
> Will do my best to set up more animations.
>
> I think the travelling transversal waves are often misinterpreted as
> longitudinal movements
> because of their travelling direction in the longitudinal direction with a
> wavespeed usually denoted as "c".
> The real longitudinal waves in the wood play the same minor or even
> negligible role in the soundboard
> as the rotational vibrations in the strings in my opinion, because they 
> have
> no coupling to the air.
> (not in the strings,.where they can cause serious ringing).
>
> regards,
>
> Bernhard
>
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