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<DIV><FONT face=Arial>So what about the high treble? Often the top =
octave or
more is quite lively, loud and brilliant.</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>Terry Farrell</FONT></DIV>
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style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
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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=mcpiano@globetrotter.net
href="mailto:mcpiano@globetrotter.net">Marcel Carey</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> Sunday, October 05, 2003 =
5:49
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> RE: RC vs CC =
again</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=171174021-05102003>Terry Farrell said:</SPAN></FONT></DIV>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px =
solid">
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial><SPAN class=171174021-05102003><FONT =
color=#0000ff
size=2> " </FONT></SPAN>When flat ribs are glued to a =
very dry
flat panel, no force vectors exist in the system. As the panel takes =
on
moisture and the ribs bend, the ribs will <EM>always</EM> be trying =
to pull
the panel flat. Period. If that assembly has crown, the ribs will
<EM>always</EM> try to go straight by pulling down on the panel. The =
compression forces in the panel are the only thing that has provided =
the
force necessary to bend the rib into a crown. Whether or not you =
ever load
that soundboard on top, the ribs will always be fighting the panel
compression to go flat. When you do apply a load to the top of the
soundboard, the compression on the panel will increase, but the ribs =
will do
nothing other than still try to go flat. As the crown lessens under
increasing load, the ribs will pull downward a bit less, but only =
because
they are being bent upwards less by the panel.<SPAN
class=171174021-05102003><FONT color=#0000ff
size=2> " </FONT></SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=171174021-05102003></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=171174021-05102003>The way I see it, the reason why we have =
the killer
octave problem with mostly CC boards, is that the crown produced =
with the
panel's growth will be kind of proportional to the lenght of the =
ribs. So,
with this method the treble that always have shorter ribs than the =
tenor
will have less crown in the beginning. Since compression will affect =
the
board's with aging, we end up with a dead killer octave and a no =
crown zone
exactly where the ribs get shorter...in the killer
octave.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=171174021-05102003></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN =
class=171174021-05102003>So
I guess there is no way to have a decent board assembly that will =
have a
predictable lifespan with the Compression Crowned method. It's
physics.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=171174021-05102003></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=171174021-05102003>Again, I might be wrong, but I think I've =
seen the
light.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=171174021-05102003></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=171174021-05102003>Marcel Carey, RPT</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=171174021-05102003>Sherbrooke, QC</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=171174021-05102003></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
=
class=171174021-05102003></SPAN></FONT> </DIV></BLOCKQUOTE></BLOCK=
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