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

[David Love]

Well this is an important point.  Why doesn't compressing the panel make
it stiffer?  It seems like it must?  Even if compression and stiffness
are not synonymous in this discussion, then the question is does
compression itself change the physical and acoustical properties of the
panel?  

David Love
davidlovepianos@comcast.net 

-----Original Message-----
From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On
Behalf Of Ron Nossaman
Sent: Wednesday, February 16, 2005 4:53 AM
To: Pianotech
Subject: RE: More CC vs RC questions was RE: Killer Octave & Pitch Raise


>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.

Apparently not. Compressing the panel doesn't make it stiffer. it makes
it 
more compressed, which makes the assembly stiffer because of the
geometry 
of the assembly.


>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.

If the stiffness of the panel changed with compression, I would agree. 
Since it doesn't (how could it?), it's the assembly that is doing the
work. 
Since the RC&S board will almost certainly have different degrees of 
stiffness and different spring rates in different parts of the assembly
to 
a greater degree than does the CC board, they will likely not sound 
identical. Compression levels in the panel are not, however, the reason 
they sound different. Opinions will always vary on this point.

It was never the intent of makers of RC&S boards that they should sound 
exactly like CC boards. We want them to sound good, and the many CC
boards 
out there that don't sound good are what drives the desire to try and 
eliminate the down-side. Dale said it well. We're trying to keep the
best 
features of the CC board without their inherent problems and
inconsistencies.

Ron N

_______________________________________________
pianotech list info: https://www.moypiano.com/resources/#archives