More CC vs RC questions was RE: Killer Octave & Pitch Raise

[Ron Nossaman]

>Another very basic question about these design elements:  Is there a 
>difference between tension in the panel and stiffness of the panel?

Absolutely, and I assume you mean stress, or compression rather than tension.


>I mean that in terms of the physical properties of the 
>panel.  Intuitively, it seems that the CC board would be under greater 
>tension owing to the crowing process.

Intellectually, scientifically, logically, and rather obviously, the CC 
panel will be under considerably more compression. The ribs of an RC board 
under string bearing load will be under more stress than those of a CC 
board. This is the intent of RC&S construction method - to take stress out 
of the panel and put it in the ribs where it will do less damage, making 
crown, stiffness, and resulting tonal qualities more dependably long lived.


>While the same amount of stiffness might be achieved by how the board is 
>loaded and the amount of bearing, does tension (whatever that is) play a 
>role in tonal output?

I seriously doubt it. The resulting stiffness increase, however, definitely 
does. How do you separate the two to find out? By building a RC&S board 
that doesn't have destructive levels of compression in the panel, but is 
still as stiff or stiffer than the CC board and listening to the result.


>Another question is this:  A CC board, as we've discussed, runs a greater 
>risk of compression set and cellular wood damage due to the fact that it 
>bears some of the load that is born by the ribs to a greater degree in a 
>RC board.  Do I have that right?

No. The CC board panel bears not only ALL of the load, it must bend the 
ribs as well to crown. The RC board panel will bear some of the load and 
the ribs will bear some, and the RC&S board panel will bear nearly none of 
the load while the ribs bear nearly all.


>If that's the case, how do we know that it isn't the fact that the panel 
>bears more of the load that contributes to the tonal output.

By building RC&S boards and listening to the result.


>While the ribs may bear the load and spare the panel to some degree, is 
>there not a tonal price to be paid for that.

What price? I can't tell by listening whether the board is CC, RC, or RC&S. 
Can you?


>Which isn't to say that an RC board can't be made to sound acceptable or 
>good, they obviously can, but will it sound different by virtue of the 
>type of crowning and what is that difference, if any?  I think that's an 
>important question.

Different? Can any two CC boards sound identical? Can any two boards of any 
construction sound identical, and if so, what is the ideal sound to shoot 
for? It's an impossible question. Again, can you tell by listening what 
crowning method was used? That's the important question to my mind.

Ron N