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<dl><br>
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</dl>Hi Kevin and Johnathan,<br>
I think what you are referring to, is a phenomena known as string
coupling.<br>
Typically it is in the .1 to .2 cent range. ( Just audible to me. 1 or 2
cents would be clearly audible) For a long time I thought it appeared
random and more noticeable in the treble.<br>
Since I have been observing the effect with respect to rib
location. I am stating to conclude that the effect, is greater at
the mid point between the ribs.<br>
Stiffness of the board is critical in the treble, and I think that is why
it is most noticeable in this register.<br>
I suspect that the effect is proportional to the fundamental frequency,
and the stiffness of the board in any particular area. This is why
I think it is less noticeable in the lower registers. Just a rambling
theory.<br>
I have not measured enough pianos to really have a firm opinion on the
subject.<br>
Regards Roger<br><br>
<br><br>
<br>
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<dl>
<dd>Somewhat off topic (or is it) ... I remember Virgil Smith doing
a study<br>
<dd>here once where he showed that tuning unisons caused the pitch level
of<br>
<dd>the note to drop. I believe it was something like 1-2
cents. (anyone<br>
<dd>know what I'm talking about, or have I gone mad?)<br>
<dd> <br>
<dd><font face="arial" size=2> I saw that demonstration
too. In our class, it could be demonstrated by hearing the beat rate of
the third tenth octave check, but they had trouble measuring it with a
machine.</i></b></font><br>
<dd><font face="arial" size=2> Kevin E.
Ramsey</font><br><br>
</i></b><br>
<dd>Jonathan Finger RPT.<br>
<dd>Boulder Chapter, PTG<br>
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