<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; =
charset=us-ascii">
<TITLE>Message</TITLE>
<META content="MSHTML 6.00.2900.2604" name=GENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=#ffffff>
<DIV><SPAN class=203290123-11022005><FONT face=Arial color=#0000ff =
size=2>Structurally, it seems to me that the bridge would be least =
likely to
roll at the greatest point of curvature. Consider a piece of steel, 1" =
wide,
1/8" thick, 2 feet long, welded to a thin piece of sheet metal on edge. =
This is
our bridge on the soundboard, easy to rotate forward and backward. It =
has no
support behind or before it. </FONT></SPAN></DIV>
<DIV><SPAN class=203290123-11022005><FONT face=Arial color=#0000ff =
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=203290123-11022005><FONT face=Arial color=#0000ff =
size=2>Now
imagine the bar stock bent into an L shape welded on edge on the =
sheet
metal. Near the bend, the corner of the L, the bar stock will be very =
strong and
resistant to rolling. It has the leg behind it to support the direction =
of the
loading. But as force is applied closer to the ends of the legs it will =
loose
strength and rotate easier in that local area. </FONT></SPAN></DIV>
<DIV><SPAN class=203290123-11022005><FONT face=Arial color=#0000ff =
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=203290123-11022005><FONT face=Arial color=#0000ff =
size=2>Dean
May</FONT></SPAN></DIV>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
<DIV></DIV>
<DIV class=OutlookMessageHeader lang=en-us dir=ltr =
align=left><FONT
face=Tahoma size=2>-----Original Message-----<BR><B>From:</B>
pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] <B>On =
Behalf Of
</B>Terry<BR><B>Sent:</B> Friday, February 11, 2005 5:23 =
PM<BR><B>To:</B>
pianotech@ptg.org<BR><B>Subject:</B> Killer Octave & Pitch
Raise<BR><BR></FONT></DIV>
<DIV><FONT face=Arial size=2>When I raise the pitch of a piano, =
typically I
find that I need to pull an area of the treble, commonly around the =
sixth
octave or so, a bit extra so that area does not end up flat when the =
pitch
raise is completed. I use typical pitch raise overpulls - 20% in bass, =
25% in
tenor and 33% or so in treble - but that one octave or so in the =
treble needs
to go a little further - maybe 35 or 38%. I find this to be true on =
most
pianos.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>My understanding is that one factor =
that may
conspire to produce a killer octave (low volume and/or short sustain) =
in a
piano is the fact that the killer octave area is also
the area the long bridge is curved most - rather than having =
the
downbearing supported in part by a straight (or nearly so) bridge =
(like in the
tenor), the curved part of the long bridge in the killer octave area =
is more
prone to rolling - I know, not rolling - actually soundboard =
deformation - but
I'm trying to point out that it can rotate in this area more easily =
than other
areas.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>My question is - might these two =
phenomena
be related? Is the killer octave area more prone to going flat because =
the
bridge is rotating (I suppose in part due to soundboard not having =
enough
support in that area)?</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Thanks for any thoughts.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Terry
Farrell</FONT></DIV></BLOCKQUOTE></BODY></HTML>