Cases and rims, ash and such...

[gordon stelter]

> > And SOME energy escapes the
> > soundboard via the rim-to-board glue joint,
> 
> Is much lost to a good glue joint? Maybe if it were
> falling apart.

Au contraire, mon frere! The better the joint, the
more is lost due to transmission through the glue.
BUT, I do suspect that a board which is flexed near
the rim due to crown and a  proper rast-to-board
contour relationship will reflect more energy back to
the board, as a slight node is created in the stressed
"kink" at this juncture.
> 
> > then
> > travels around the rim wood to re-enter the
> soundboard
> > at another point than its preferred point of
> entry,
> > the bridge.
> 
> Now this is sounding like a marketing brochure with
> 8X10 color glossy photos with circles and arrows and
> a paragraph on the back of each one.

So what? Perhaps it is so!  Put a  tuning fork on a 
piano leg and you will hear the board resonate. Play a
note and you can feel the case vibrate with your
fingers. Granted, recycling truant vibrations is not
the primary means of sound production, but it is
better that these vibrations get another chance to be
transformed into sound than that they get dissipated
by heat in a cheap, soft rim or case. Ever tuned one
of those Yamaha uprights with  a particle board case?
They sound awfully "thuddy" to me! 
     Now, compare that with one of our admired Knabes
from the late 19th century. These pianos have a  very
"hard", distinct tone. Why? In my opinion, it is
because the ash/rosewood/ebony rims and cases do not
dampen the higher harmonics of vibrational energy as
it escapes the soundboard into the rim and case, and
then transfers it, partially, back into the board.
> 
> > be absorbed by it and transmuted into heat. So the
> > cases were of hardwoods. And I am sure that you
> will
> > agree that these pianos have a vital, "stirring"
> > quality to their sound, 
> > lacking in other pianos.
> 
> 
> Yeah, so they had massive hard-hardwood rims that
> effectively terminated the soundboard and tended to
> not dampen the soundboard. 

In my opinion they either deflected or accepted and
transmitted the vibrations, but they did not absorb
them. Deflection is best. Transmission is next best.
Absorption is no good ( see particle board case,
above. )

Do little vibrations
> really travel 'round and 'round and re-enter a
> soundboard?

Some, yes. I am certain of this.
> 
> >     You said that you liked pianos with ash beams.
> So
> > do I. And the beams were built of ash
> because.......
> > ???
> 
> I think I said I have a couple pianos with massive
> ash rims. Haven't seen too many ash beams/braces,
> although I can't imagine why ash would not make for
> a good beam. I think ash makes for a good rim
> because it is hard and massive, much like hard
> maple.
> 
> >      Thump
> > 
> > 


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