Cases and rims, ash and such...

[gordon stelter]

> Most energy that gets into the rim is damped. Very
> little is radiated to the
> air as sound energy. All wood has internal
> resistance. It is this resistance
> that dampens the wave energy that is coupled to it
> from the soundboard. It's
> a loss, loss situation.

Dear Del,
    I do believe that another term for "damped" would
be absorbed. In either case, I believe that we may 
agree that the softer the material, the more this will
occur. On a molecular level, this means that
not-too-tighly compacted molecules are being jostled
by the vibrational energy which escapes into the
rim/case, and this jostling and rubbing together of
atomic elements creates friction, resulting in what we
call "heat".
    What I am saying is that manufacturers such as 
Wm. Knabe and Geo.P.Bent seemed to consider this
potential for energy loss in the case and rim wood as
a correctible negative, and in the highly competitive
atmosphere of piano building in the late 19th energy,
when "no stone was left unturned" in the pursuit of
"perfection", adressed it by using the most rock-hard,
yet machineable woods they could find for rims and
cases. 
   Personally, I do not believe that these efforts
were for nought, as I can easily hear a distinct
characteristic of tone in pianos which were
constructed in this fashion.
    And as I do not believe that dense, hard, woods
are terrific resonators, I assume that it is their
propensity for transmission and re-transmission of
vibrations back the board, including to portions not
energized by the initial shockwave, by certain
frequencies, which caused this. Echoes diminish in
intensity as they progress. But they do occur.
    In short:  I believe that I can tell when a  piano
is built this way, merely by hearing it. And I like
it.
     Thump



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