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

[Erwinspiano@aol.com]

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Dave & all
  I was going to stay out of it but...I've been skimming  & following this 
thread. Been busy. First David I think you're asking all  the right questions 
About panel stiffness etc. Much of this is tonal difference  is unquantifiable 
but apparently there are observable subjective tonal  differences between 
compressed & more compressed panel assemblies. You have  some experience with both 
,So I ask you, it sounds like your not quite happy  with the sound of the 
competely RC&S board as compared to a the best  C.C. board or R.C.  boards.
 If that's true then understand why your asking the  questions. There's 
something missing that you like.
   Just a couple points. there has been some recent  discussion as to the 
absorptive nature of spruce panels. Though it's the overall  stiffness of the 
entire C.C. board system. Although sound travels fastest along  the grain  .i.e. 
approximate. 5000 ft per second it still travels plenty  fast cross grains 
well.(3000 ish) not sure.
   I suspect (can't prove it.) but compressing  the wood fibers at least some 
cross grain also makes the panel more  reactive. Any time something is put 
under tension compression it gets more  reactive to movement .ie.drum heads, 
strings of all kinds, beams under load  & people under stress(grin). This one 
argument is why I believe that some  compression is benificial to the sound of a 
system. The other is that all the  best sounding C.C. board I heard had lots 
of compression & hence cracks.  Even after compression set & some loss od crown 
they still sounded better  than the one that escaped the factory without 
being suffiecently dry for the  C.C. system to belly up. These had little crown or 
vitality & also no cracks  but hey not much sound either. No it's not the 
whole equation but some of this  makes intuitive & kinesthetic sense to me.
  The other reason I like very tight grain spruce is that  I get the most 
lively sound with it & it isn't because I'm compressing it to  death but that its 
denser material & has excellent impedance qualities in  & of itself. JMHO. 
But I've done it enough times now to have a strong  opinion about it.
  It's true as Ron O said , I may change my mind &  you all have changed my 
mind plenty but I also have to go with what works in my  evolutionary journey 
in the sound board biz. IN the long run only one broad  & wide tonal results 
are going to make my ears  & the clients  happy & that's a piano that sings like 
a soprano with the biggest lungs you  ever heard a color range any 
kindergartner could make a Picasso  with.
  I think you hit the nail on the head. How stiff is  stiff enough. That's is 
the question Nick Gravagne & I ask each other  periodically & one were all 
asking right now. Some of us like the answers  we've come up with even though 
they may vary some or a lot. 
  We can't make sound boards last forever but we can make  them sing way 
beyond our lifetimes & any technique moving away from a purely  C.C. board will 
give a longer life with more predictability. At the end of the  day we have to 
decide what were willing to live with and go with it. We should  be able to to 
stick our heads in the piano & smile or go back to the  drawing board. I 
prefer to smile.
  Good discussion.
    Dale
 Ps Dave Porritt, good thoughts
   
 

I didn't  want this discussion to dry up too quickly as I still have a
few--at  least--unanswered questions.

So let's amplify this point a bit for my  own clarification (forgive me,
I'm a bit slow sometimes).  It stands  to reason that the uncompressed
panel is less stiff than the compressed  panel, I think we agree on that.
The overall stiffness of the entire  assembly (CC vs RC&S), however, is
relatively the same because the ribs  in the RC&S board are stiffer than
in the CC board and the way the  panel and ribs combine produce an
overall stiffness measured in terms of  the whole assembly.  But if the
panel in the RC&S board is  somewhat less stiff than the compressed panel
in the CC board how would you  not expect that to have some effect on the
tone?  While the assemblies  may both move up and down at the same rate,
might the overall stiffness of  the panel, as opposed to the overall
assembly, have an effect, say, on  which partials are damped and which
are not and the balance of those?   So if the slightly less stiff panel
has a greater damping effect, then the  perception would be a somewhat
less lively or expressive, for lack of  better words, tone.  I guess that
was a question.

David  Love
davidlovepianos@comcast.net 





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