Downbearing / crown support question.

[Stéphane Collin]

Hi Ric.

Same reaction here :  why consider ribs if their role in supporting 
downbearing force is neant ?  The only accepted theory for now is that 
(apart from sustaining the downbearing forces) the ribs help the sound wave 
travelling across the grain of the pannel.  Now, who said that this is 
important ?  I believe that the pannel (soundboard) must be under some 
compression to sound well.  Same for strings : they must have some tension 
to sound well.  I tink this has to deal with some internal frictions in both 
cases.  Do you think a board where the ribs sustain all of the downbearing 
forces, and a pannel freely posed on these ribs, without bearing any force, 
would sound good ?  My answer is not, but I never tried this at home.

Best regards.

Stéphane Collin.


----- Original Message ----- 
From: "Ric Brekne" <ricbrek at broadpark.no>
To: "pianotech" <pianotech at ptg.org>
Sent: Friday, June 16, 2006 9:04 PM
Subject: Downbearing / crown support question.


>I suppose most of the rebuilders are already on the road to Rochester... 
>but I thought I'd ask anyways....
>
> Assuming for the moment that one could provide adequate and total support 
> for crown and downbearing completely independant of ribs in a standard 
> single ply panel.... what would the primary design considerations for ribs 
> be ?
>
> Cheers
> RicB
>
>