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<DIV><SPAN class=114315606-07072006><FONT face=Arial size=4> I
do many many many pitch raises -- almost every piano I tune, for the last 27
years. (Almost everybody lets them go too long.)</FONT></SPAN></DIV>
<DIV><SPAN class=114315606-07072006><FONT face=Arial size=4>
I've found that the ideal average overpull is halfway between 1/3 to 1/2 the
amount sharp as it was flat. In other words, a 41% overpull of the amount
it was</FONT></SPAN><FONT face=Arial><FONT size=4><SPAN
class=114315606-07072006><FONT> flat. For an easy-figuring example, say
the piano is 18 cents flat. Half of that is 9 cents and a third of that is
6 cents. Half-way between 6 and 9 is 7.5, so I pull it 7.5 cents sharp,
and almost invariably A4 ends up right on 440 Hz, or very close.
</FONT></SPAN></FONT></FONT></DIV>
<DIV><SPAN class=114315606-07072006> <FONT face=Arial
size=4>However, if the piano is a half-step flat, I don't pull it 41 cents
sharp. That would be too much. There's some degree of flatness where
the usually-id</FONT></SPAN><SPAN class=114315606-07072006><FONT face=Arial
size=4>eal 41% overpull has to taper off. For a half-step pitch raise, I
usually overpull so that A4 is beating about 5 beats sharp. That's
approximately 20 cents, I believe. Sometimes more is required, sometimes
less. It varies. That's here in Denver -- probably different
elsewhere. </FONT></SPAN></DIV>
<DIV><SPAN class=114315606-07072006><FONT face=Arial
size=4> But what I often experience is: even though
after the pitch raise, A</FONT></SPAN><SPAN class=114315606-07072006><FONT
face=Arial size=4>4 is at 440; after I've gone through the
fine tuning and </FONT></SPAN><SPAN
class=114315606-07072006><FONT face=Arial size=4> pulled in unisons, when I go
back to do the final check and touch up anything that has slipped, I find
that the whole middle section is sharp! Why?</FONT></SPAN></DIV>
<DIV><SPAN class=114315606-07072006><FONT face=Arial
size=4> --David Nereson, RPT</FONT></SPAN></DIV>
<DIV><SPAN class=114315606-07072006> </SPAN></DIV>
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