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<DIV><FONT face=Arial size=2>Allen,</FONT></DIV>
<DIV><FONT face=Arial size=2>Not a lot of hope, short of redesigning the
piano.</FONT></DIV>
<DIV><FONT face=Arial size=2>The longitudinal partial is being excited by the
combined energies of the 7th and 8th partials.</FONT></DIV>
<DIV><FONT face=Arial size=2>If you can get the hammer to strike at exactly
1/7th or 1/8th of the string length, it may reduce the energy enough to stop the
sound. This may be the reason for the old design rule to strike at 1/7th of the
string length.</FONT></DIV>
<DIV><FONT face=Arial size=2>On smaller pianos the longitudinal mode may be at
the 17th or 19th partials of plain wire strings.</FONT></DIV>
<DIV><FONT face=Arial size=2>Ed Sutton</FONT></DIV>
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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=akwright@btopenworld.com href="">Allen Wright</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=ed440@mindspring.com
href="">Ed Sutton</A> ; <A title=pianotech@ptg.org href="">Pianotech List</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Saturday, July 12, 2008 6:23
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: String noises
revisited</DIV>
<DIV><BR></DIV>Ed,
<DIV><BR></DIV>
<DIV>This sounds like an exact description of what I'm dealing with. Octave
three - 15th partial - disappears with pitch change; all yes.</DIV>
<DIV><BR></DIV>
<DIV>I want to read Jim's book now....does he suggest any fix for this, or is
it a scaling problem (or simply unavoidable) or what?</DIV>
<DIV><BR></DIV>
<DIV>Allen</DIV>
<DIV><BR></DIV>
<DIV><BR>
<DIV>
<DIV>On Jul 12, 2008, at 2:38 AM, Ed Sutton wrote:</DIV><BR
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<DIV><FONT face=Arial size=2>Allen-</FONT></DIV>
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<DIV><FONT face=Arial size=2>If I understand Jim Ellis' book, in a 7 foot
grand piano, longitudinal mode noises will tend to occur in octave 3, and
they will tend almost always to be at or near the frequency of the 15th
partial. There will probably be a slight delay after the attack and before
the sound develops. If you make slight changes in the pitch of the string,
the longitudinal mode sound will not change pitch, but will disappear when
the pitch has changed such that the modes that excite the longitudinal mode
are outside of its resonance band.</FONT></DIV>
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