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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>
<A title=mfarrel2@tampabay.rr.com
href="mailto:mfarrel2@tampabay.rr.com">Farrell</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A =
title=pianotech@ptg.org
href="mailto:pianotech@ptg.org">Pianotech</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Wednesday, January 28, =
2004 12:39
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Permanent =
Soundboard
Crown!</DIV>
<DIV><BR></DIV>
<DIV class=block>
<P><FONT face=Arial size=2><EM>Studies made by Bluthner research =
and
development department have proven that tensions and compressions =
develop on
the edges that are inhomogeneous and not controllable. In contrast, =
the
soundboard that Bluthner has developed has a cylindrical curvature so =
that the
tension of the soundboard can be exactly defined. The ribs are planed =
to fit
the curvature needed and therefore the tension of the soundboard =
remains
intact over the decades. In fact, even under difficult climatic =
conditions the
curvature will remain in a constant form since not only the rib =
structure will
hold it in place but also the red beech inner rim is preformed to the =
correct
angle to receive and retain the soundboard's curve tension. Because =
the
soundboard is pre-stressed in this fashion it can be fitted exactly =
and
<U>remain under curve tension permanently.</U> The bridge, of course, =
is
adapted to the tension and curvature of the soundboard in its optimum
position. This ensures that string vibrations in their full spectrum =
are
transferred to the soundboard. By utilizing the resonating surface, =
the
special design of the Bluthner soundboard generates tone significantly =
better.
</EM></FONT></P></DIV></BLOCKQUOTE>
<P dir=ltr><FONT face=Arial size=2>The way I understand the =
above text,
Bluethner uses crowned ribs and doesn't rely (at least not much) on =
panel
compression to achieve crown. </FONT></P>
<P dir=ltr><FONT face=Arial size=2>They want a cylindrical crown, =
as opposed to
the spherical crown advocated by piano designers such as Klaus Fenner, =
who wants
the board to be curved not only along the ribs, but also (roughly) along =
the
bridge, with a high point at a certain location. Fenner favours
compression-crowning and has some theories about stresses that need to =
exist not
only in the soundboard, but also in the rim etc. to get a good =
sound.</FONT></P>
<P dir=ltr><FONT face=Arial size=2>I've read both Klaus Fenner's =
and Ingbert
Bluethner-Haessler's books on piano construction, that's how I learned =
about the
differences. </FONT></P>
<P dir=ltr><FONT face=Arial size=2>The text posted by Terry F. is =
pretty
confusing when taken alone - probably because it is translated from =
German
;-)</FONT></P>
<P dir=ltr><FONT face=Arial size=2> Calin
Tantareanu<BR>----------------------------------------------------<BR>&nb=
sp;<A
href="http://calintantareanu.tripod.com">http://calintantareanu.tripod.=
com</A><BR>----------------------------------------------------</FONT></P=
>
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