Steingræber and CC boards

[Overs Pianos]

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>At 12:13 AM +0200 20/10/03, Richard Brekne wrote:
>
>. . . I also asked [Mr Steingr=E6ber] about the=20
>criticisms of CC panels, and Rib crowning as
>an alternative. His response can be summed up by saying that CC panels
>are quite dependable and have outstanding longevity characteristics as
>long as they are contrived with the proper care and knowhow. And
>concerning the Rib crowned panel, his position was that these were
>acoustically inferiour.... tho I didnt get time to really nail him down
>on a more specific reasoning for that opinion.

This leads to a further question. Has Mr=20
Steingr=E6ber actually built an RC board to=20
establish the view that he holds, or is it that=20
since he doesn't use rib crowning, that it is=20
better for his production credibility to discount=20
the technique out of hand?

I find it highly unlikely that one construction=20
technique would have a propensity to produce a=20
superior tone over the other. The real advantages=20
that I see with RC&S construction are=20
repeatability and longevity. The spring rate of a=20
panel must surely influence its response. I=20
suspect that the spring rate of either type would=20
be a more critical factor that the construction=20
method used (in the short term at least). I=20
recall Ron Nossaman mentioning this some time=20
back, but no-one seemed to take it up at the time.

I believe it would be possible to build either a=20
CC, an RC or an RC&S panel with whatever spring=20
rate the maker desired (the 10 mm thick panels we=20
see in the KG series compression crowned Kawais,=20
must surely have been used to achieve a higher=20
spring rate - with hopefully longer sustain -=20
than those CC instruments with thinner panels. We=20
have a KG5 coming in for a rebuild next week -=20
the earlier type with the Oak belly rail and back=20
beams - the bridges will have to go since they're=20
not quarter cut, but the panel remains an unknown=20
until it is investigated further). Furthermore,=20
since the CC and RC approach are entirely=20
different in their method of supporting crown, I=20
failed to see the utility of the discussion which=20
ensued a few a weeks ago, when there was much=20
speculation about the relative stiffness of a=20
pair of identically dimensioned CC and RC&S=20
boards.

We have just completed the construction of a pure=20
RC&S laminated panel sound board (while our=20
previous instrument - no. 3 - had a board which=20
was very close to pure RC, this new sound board=20
features a completely new rib design - patent=20
pending). The strings should be going on by the=20
second week in November. I will report to the=20
list with my first impressions when I get it=20
together. We have been building piano no. 5=20
alongside no. 4. But I have held off on the=20
construction of the sound board for no. 5 until I=20
hear no. 4 'in song' - just in case I decide to=20
change the spring rate.

BTW Dale, your posts have been interesting. And=20
David L., I use a similar technique as the one=20
you described for replacing a bridge.

Ron O.
-- 
OVERS PIANOS - SYDNEY
    Grand Piano Manufacturers
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