<!doctype html public "-//w3c//dtd html 4.0 transitional//en"> <html>   Ron Nossaman wrote: <blockquote TYPE=CITE>  >>>Wrong. As we've discussed specifically and often, the RC board can be made >>much stiffer, both unstrung and strung, though the CC board will often have >>a steeper spring rate progression under deflection, at least while the >>crown lasts. >> >Well.. you'll excuse me if I find this directly above in direct conflict >with >"the one with the higher panel compression level will have the steeper >spring rate gradient, and will be stiffer." What do you find that's conflicting, and how can you possibly interpret this to mean that I said compression crowned boards are categorically stiffer than rib crowned? How about the real stuff instead of the game?</blockquote> First off.. I said nothing about categorically.. nowhere.. not even closely or remotely or anything else..In fact I quite obviously placed several conditions and qualifiers to get at what I thought was a simple little point I had a question about.  Second... since you asked, I find it conflicting to say in one sentence that "the one with the higher panel compression level will have the steeper spring rate gradient, and will be stiffer." and then say "the RC board can be made much stiffer, both unstrung and strung, though the CC board will often have a steeper spring rate progression under deflection,..." Jimmenees there Ron.. I'm not attacking you or anything... Just trying to sort out on my own what some of the justification for using a CC board must be in the minds of its advocates. There is no game here... no competition... nothing except a simple question. <blockquote TYPE=CITE>>and please remember the qualifiers for this example so as to keep it in >context.... it was  equal crown at same RH, and further we were to leave >all other compression damage issues aside for a moment. Yes, do remember the qualifiers. Or better yet, go back up and read it again and you will see that the rib crowned board I proposed was assembled without drying the panel at all. While you're at it, re-acquaint yourself with the fact that this is one specific example, put forth to John Hartman indicating that there is more to what determines assembly stiffness than merely cross section and mass of the components, and that identical looking assemblies aren't necessarily equally stiff. That's what I meant to say, that's what I said as far as I'm concerned, and if you think there's anything there (in context) indicating that I said compression crowned boards are categorically stiffer than rib crowned, make your case. Again, the real stuff please.</blockquote> Again... the real stuff is that I said nothing about catagorically.. I went out of my way to isolate a bunch of factors out of the picture.... which you for some reason just ignore. There is no catagorically thingy here. And the qualifiers were not origionally your own.. they were Johns...  he said on thursday last...   <blockquote>"O.K. I will say it again. If two or more soundboards have the same dimensioned ribs and the same panel thickness and THE SAME CROWN at the same EMC. Then the two Soundbaords assemblies will have the same stiffness even if the method of crowning is not the same."</blockquote> This quote followed your example experiement that specifically mentioned the same EMC ... and while we are on that post  you state <blockquote>"Of the three, the rib crowned assembly  with the non-compressed panel will be the least stiff, the compression  crowned with straight rib will be stiffer, and the combination  compression and rib crowned assembly will be stiffest."</blockquote> Again... you seem to say one thing here and the other there.... And YES... I know better then to think this in anything else then something that just needs clarifying... at least to me... which is why I asked.... for christs sake. <blockquote TYPE=CITE>  >Real science Ron... means also answering a question in the context it was >given with qualifiers intact... and do me a favour... dispence with the >scolding routine.  And FWIW the term "so-called" isnt a derogatory. We're still putting the qualifiers back in my original statement before we go anywhere with yours. Derogatory or not, compression set still exists, and is still real science.</blockquote> Nobody said or hinted at anything else. <blockquote TYPE=CITE>  >>Yes, if you design the ribs to support the crown without needing panel >>compression to do so, and don't dry the panel to extremes, panel >>compression is no longer a problem. This should start sounding familiar >>about any time now. >Again.. thats not the question I asked.... Or perhaps you are saying that >under no circumstances can the constraint placed by the ribs on the panel >cause problems regardless of climatic conditions ? Of course not. Nothing can survive any conceivable climate condition. If you need that kind of absolute, I'll leave you to it. I sure don't know how to build anything that's utterly indestructible.</blockquote> Thats a cop out. <blockquote TYPE=CITE>  >I asked if there was a way of contriving a rib such that it was a bit less >constraining to the panel ... as in either compression or tension. And that's the question I answered.</blockquote> No it isnt... but no bother...Del already took care of most of this, in an appreciated fashion as well. <blockquote TYPE=CITE>  Ron N  </blockquote> -- Richard Brekne RPT, N.P.T.F. UiB, Bergen, Norway <A HREF="mailto:rbrekne@broadpark.no">mailto:rbrekne@broadpark.no</A> <A HREF="http://home.broadpark.no/~rbrekne/ricmain.html">http://home.broadpark.no/~rbrekne/ricmain.html</A> <A HREF="http://www.hf.uib.no/grieg/personer/cv_RB.html">http://www.hf.uib.no/grieg/personer/cv_RB.html</A>  </html>