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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=Richard.Brekne@grieg.uib.no
href="mailto:Richard.Brekne@grieg.uib.no">Richard Brekne</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A =
title=pianotech@ptg.org
href="mailto:pianotech@ptg.org">pianotech@ptg.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> December 03, 2001 12:04 =
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Negative bearing
(long)</DIV>
<DIV><FONT color=#000080 size=2></FONT><FONT color=#000080
size=2></FONT><BR></DIV>
<P>Been reading and weeding through and find much that is interesting, =
but
this comment caught my eye and I must admit is confusing. I wrote =
about modal
analysis a year and a half back and you came out and said it was =
basically
useless in designing soundboards, since the conditions for measurement =
are
different then the conditions for full strung, and if done full strung =
well
the deed is already done so to speak... further you pointed out then =
that you
meant that there was no reliable way of forcasting said =
changes.
</P></BLOCKQUOTE>
<P dir=ltr><FONT color=#000080 size=2>OK. My previous answer was =
incomplete. But
you're taking what I said out of context. What I said was, "</FONT><FONT =
color=#000080 size=2>One of the problems I have with most of the =
testing I have
seen on the piano soundboard is that it was done on an unloaded board =
and is,
therefore, largely meaningless." This is some different than you are =
implying
above. It is my opinion that tests of this type are basically =
meaningless unless
they are done on soundboards installed in a real world piano, strung and =
loaded.
Remember, we're not just trying to figure out the specific =
characteristics of
the soundboard alone, but the entire, interactive system. No where do I =
preclude
the possibility of obtain useable results from pianos that are strung =
and at
pitch.</FONT></P>
<P dir=ltr><FONT color=#000080 size=2>The reason they are not =
generally done
this way is simple. It's very difficult to do. You need full access to =
the
soundboard and the plate is in the way on the top while the belly =
bracing is in
the way on the bottom. Therefore to conduct a meaningful test something =
is going
to have to go. Since it won't be the plate it will have to be the belly =
bracing.
Before everyone panics, most pianos won't fly into a million pieces if =
the belly
braces are removed. But it will be difficult and expensive. Hence, it's =
not
done.</FONT></P>
<P dir=ltr><FONT color=#000080 size=2></FONT> </P>
<BLOCKQUOTE dir=ltr
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<P>> Hmmm.. In the section of the Wogram article entitled =
"Influence of
<BR>> string tension" He seems to be saying that the condition =
of an
uloaded > soundboard is not a problem. He says that the basic
impedance curve > and sound radiation curves remain basically =
the same
and that only the > lowest resonances are effected and that =
the effect
is predictable <BR>> enough to take into consideration. <BR>> Is =
this
outdated ?? </P></BLOCKQUOTE>
<P dir=ltr><FONT color=#000080 size=2>I don't know if it is =
outdated or not. I
disagreed with Mr Wogram's position on this when I first read that =
article and I
still do. My experience is different than his. I don't know enough of =
the
details of his work to have even the vaguest notion of what all might be =
different.</FONT>
<P dir=ltr><FONT color=#000080 size=2></FONT>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000080 2px solid; MARGIN-RIGHT: 0px">
<P>I consider modal analysis of the working soundboard to be a good =
first
step. <BR>You know, like, "one small step for man...."
<P>Del</P></BLOCKQUOTE>
<P dir=ltr><FONT color=#000080 size=2>I still believe this. It's =
not going to be
the final word, but it can certainly help us along the way.</FONT>
<P dir=ltr><FONT color=#000080 size=2></FONT>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000080 2px solid; MARGIN-RIGHT: 0px">
<P>Stephen Birkett wrote: > <BR>> I have my opinions about =
modal
analysis (mentioned here once a <BR>> while back)...that, at best, =
it can
tell you that the soundboard is <BR>> working as you already know =
that it
is supposed to work. As a practical <BR>> tool for design I have my =
doubts
it will ever give anything, primarily <BR>> because it treats the =
sb
unloaded and in isolation from the interactions <BR>> with the rest =
of the
piano.</P></BLOCKQUOTE>
<P dir=ltr><FONT color=#000080 size=2>Well, as I said. In my =
opinion the
soundboard must be loaded with real world strings. None of the published =
tests I
have seen so far have been done this way.</FONT>
<P dir=ltr><FONT color=#000080 size=2>Del</FONT></P></BODY></HTML>