circle of sound

Richard Brekne Richard.Brekne@grieg.uib.no
Sun, 23 Jan 2005 22:59:27 +0100


Erwinspiano@aol.com wrote:

>  
>
>     Ron O. write
>
>  Possibly, the ribs on the bigger pianos are also
> quite heavy relative to their strength. The
> Imperial ribs are nominally 30mm wide by 23 mm
> high.
>    Hi Ron .O
>   If the Bozy had ribs 30 high by 23 wide ,which, is reverse of the 
> above, then perhaps a different tonal result at the higher dyanmic 
> levels would be more likely. Whadda ya think ?
>   My goodness this is a very flimsy rib for a massive piano but then 
> this to me  would indicate a purely compression crowned board

You touch on a point I've been scratchin my head about for 4 years 
now... relates to a disscussion between myself, Delwin, and Andre back 
then.  How (if possible at all)  a compression board... with smaller 
dimmensioned ribs and more reliance on the compression of the panel for 
stiffness can be made to yield the same... or nearly same acoustical 
results as a rib crowned board which uses larger dimensioned ribs to 
achieve the same stiffness.  At best it would seem to me that their 
might be some RH level where the two might be somewhat similiar... but 
the requirement for greater rib mass in rib crowned assemblies alters 
the stiffness to mass ratio, and if its compensated in any sence of the  
word by less panel mass then at the very least the distribution of mass 
is quite different. Still looking for a good explanation here.

>    Dale


Cheers
RicB

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