<!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 6.00.6000.16414" name=GENERATOR></HEAD> <BODY text=#000000 bgColor=#ffffff> <DIV><SPAN class=875293502-20082007><FONT face=Arial color=#0000ff size=2>So setting the back duplex is more or less a process of massaging that so-called non-speaking length of the string until you like where it is, correct? With the amount of friction across the bridge pins I understand that once it is set it's pretty much going to stay there. </FONT></SPAN></DIV> <DIV><SPAN class=875293502-20082007><FONT face=Arial color=#0000ff size=2></FONT></SPAN> </DIV> <DIV><SPAN class=875293502-20082007><FONT face=Arial color=#0000ff size=2>Since the front duplex does change whenever you tune the piano, are we pretty much stuck with wherever it decides it's going to be once we have stabilized the string with some firm key whacks? I frequently find these much more objectionable, than the rear ones. And louder, too.</FONT></SPAN></DIV> <DIV><SPAN class=875293502-20082007><FONT face=Arial color=#0000ff size=2></FONT></SPAN> </DIV> <DIV><SPAN class=875293502-20082007><FONT face=Arial color=#0000ff size=2>-- Geoff Sykes</FONT></SPAN></DIV> <DIV><SPAN class=875293502-20082007><FONT face=Arial color=#0000ff size=2>-- Los Angeles</FONT></SPAN></DIV> <DIV><SPAN class=875293502-20082007><FONT face=Arial color=#0000ff size=2></FONT></SPAN> </DIV> <DIV><SPAN class=875293502-20082007><FONT face=Arial color=#0000ff size=2></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>Richard Brekne<BR><B>Sent:</B> Sunday, August 19, 2007 7:48 PM<BR><B>To:</B> pianotech@ptg.org<BR><B>Subject:</B> Problems With Duplex Scaling Of Pearl River Grands?<BR><BR></FONT></DIV>Tuning the back duplex (and any so called non speaking length for that matter) can and does involve both the placement of the termination devices and adjusting the tensions on those segments.<BR><BR>For example... if the back length of a given string is exactly one half of its speaking length... then this string can be tuned to exactly an octave... or slightly above an octave, or slightly below. Slightly meaning a pretty significant deviation.  Friction from the bridge pins is great enough that there is a window for variation here that will remain stable no matter how hard you play.  In other words... you can purposely put more tension or less tension on the back scale relative to the front scale and expect it to stay there over long periods of time. Or you can if you choose equalize the tension to the speaking length if you want and expect the same.<BR><BR>If your regular tuning method (for the speaking length) does not include very large movements of the string... this will not change the tension on the back length either.<BR><BR>There are a lot of ways of regulating the tension on the back scale. I use a string stretcher and apply pressure to the string as nearly horizontal and in a direction away from the bridge pin to do this.  To increase back scale tension (and hence frequency) I push on the speaking length, to decrease on the back length.  I find this allows me to actually decide the pitch of the segment as long as it is within the window of what can remain stable mentioned above.<BR><BR>Cheers<BR>RicB<BR> <BLOCKQUOTE><BR>Many of the messages on this thread are talking about a tuned front and/or<BR>rear duplex. What that duplex should be tuned to aside, how does one<BR>actually go about tuning either the front or the rear duplex?<BR><BR>-- Geoff Sykes<BR>-- Los Angeles</BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>