Killer Octave Question

[Ron Nossaman]

>Building and installing crown compressed soundboards have been told me as 
>being far way more difficult than rib crowned ones, and I see no 
>advertising about the method nowhere (and indeed most pianist should not 
>understand the difference).

There's nothing inherently more difficult about building  and installing 
compression crowned boards that I'm aware of. Who told you there is, and 
what is so difficult, according to who told you? You're right about 
pianists not understanding the difference, but then neither do techs and 
manufacturers, to a large degree.


>I have the impression too that everyone there is focusing on crown and 
>durability, while not many are comparing  the response characteristics of 
>the methods.

The only difference in response characteristics I'm aware of is that the 
compression crowned board characteristically loses crown faster, and has 
more tone production and sustain problems in the treble. What response 
characteristic differences did you have in mind?


>While building soundboard that are supposed to travel and be installed in 
>a repaired instrument far from the soundboard building place it is 
>understandable that crown compression (and not only  if I understand well) 
>is used, but how can you attain an internal assembly tension as high and 
>then a delay in springiness response with the ribs as the most active 
>elements ?

It shouldn't matter whether the board is built here or there, except that 
when someone else builds it for you, you give up control of the building 
process and take what they send you.


>Are not we using this process to build the internal spring rate of the 
>soundboard ?

Yes we are, but the internal tensions in an uninstalled soundboard aren't 
the necessary sole determinants of that spring rate except in compression 
crowned boards. What matters is the spring rate (rates, actually, since 
panel compression in a rib crowned system does have some influence) of the 
assembly after it's installed in the piano and under string bearing load. A 
rib crowned board doesn't have nearly as much built in stress, but will 
respond as well as and most likely for a longer time than a compression 
crowned board.


>Everybody agrees we could build pianos without any crown if necessary, so 
>the presence of crown is not the only proof of the taste of the pudding 
>I'd say !

I wouldn't, by a long shot. Sure, you could build a piano without crown 
(that would sound good), but not by conventional methods, with conventional 
materials, in conventional configurations changing nothing but the crown.

Ron N