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<DIV> </DIV>
<DIV>----- Original Message -----
<DIV>From: "Mary C. Smith" <<A =
href="mailto:MarySmith@mail.utexas.edu"><FONT
color=#000000>MarySmith@mail.utexas.edu</FONT></A>></DIV>
<DIV>To: <<A href="mailto:caut@ptg.org"><FONT
color=#000000>caut@ptg.org</FONT></A>></DIV>
<DIV>Sent: May 30, 2002 8:23 PM</DIV>
<DIV>Subject: Re: Accu-just HPs in Steinway D :</DIV></DIV>
<DIV><BR></DIV>
<DIV>> Weighing in with another idea of someone knowledgable to =
consult with
on<BR>> this...Del Fandrich has lots of experience designing scales =
and such.
He<BR>> might be able to shed some light on the waste length =
question. Del,
are you<BR>> reading this???<BR>> </DIV>
<DIV><FONT color=#000080></FONT> </DIV>
<DIV><FONT color=#000080></FONT> </DIV>
<DIV><FONT color=#000080>Hi Mary,</FONT></DIV>
<DIV><FONT color=#000080></FONT> </DIV>
<DIV><FONT color=#000080>Yes, I've been reading this. Most of it, at =
least.
</FONT></DIV>
<DIV><FONT color=#000080></FONT> </DIV>
<DIV><FONT color=#000080>And you should know better than to call that =
back
section of the string the 'waste length.' Or did I forget to make that
distinction? I might have. As may be, there is no 'waste length' between =
the
front string termination and the back termination. It all serves some =
function
with the possible exception of the length of string between the two =
bridge pins.
</FONT></DIV>
<DIV><FONT color=#000080></FONT> </DIV>
<DIV><FONT color=#000080><EM>The backscale -- that length of string =
between the
trailing bridge pin and whatever type of back string termination exists =
-- must
be long enough and free enough to allow the desired amount of bridge =
movement
without undo restriction. </EM></FONT></DIV>
<DIV><FONT color=#000080></FONT> </DIV>
<DIV><FONT color=#000080>Personally, I don't care whether this length =
is tuned
to some specific partial of the speaking length or not. I became =
disillusioned
with them back in the 1970s and have yet to hear a piano in which =
the
tuning of the backscale to some specific partial of the fundamental =
could
definitively be credited with improving the acoustical performance =
of the
piano. </FONT></DIV>
<DIV><FONT color=#000080></FONT> </DIV>
<DIV><FONT color=#000080>In the real world -- and by the nature of the =
piano --
it would be pretty hard to come up with any backscale string length =
scheme in
which at least some of the backscale lengths didn't end up being tuned =
closely
enough to some partials of some speaking strings to force sympathetic =
resonances
at some frequencies. In these discussions we often tend to forget that =
the
bridge does not move in individual segments, but as a unified whole. =
That is,
when the hammer at E-80 is played and it hits the strings associated =
with E-80
causing them to vibrate, the whole bridge -- or at least a good part of =
it -- is
set in motion as a result and that motion is felt for some distance =
on both
sides of the bridge pin set dedicated to E-80. That bridge motion is =
going to
force the movement of all of the other strings that are coupled to it in =
the
vicinity of E-80, both on the speaking side and on the backscale side. =
Somewhere
some of them -- probably quite a lot of them -- are going to be =
sympathetically
resonant no matter how clever we try to be with the =
backscale.</FONT></DIV>
<DIV><FONT color=#000080></FONT> </DIV>
<DIV><FONT color=#000080>Some of the so-called tuned duplex schemes in =
common
practice place a bearing bar so close behind the bridge as to =
demonstratably
impede the motion of the bridge. No amount of hammer hardening or =
fooling around
with hammer strikepoints or 'tuning' of the backscale lengths is going =
to help.
The backscale simply needs to be longer than provided for by the =
placement of
the bearing bar.</FONT></DIV>
<DIV><FONT color=#000080></FONT> </DIV>
<DIV><FONT color=#000080>I don't yet know if there is an 'optimum' =
length for
any given backscale. I do know that if the backscale lengths are too =
short both
power and sustain suffer. Personally, I'd prefer to err on the side of =
them
being too long rather than too short. (This is not an impedance issue -- =
that
is, a short backscale does not simply add stiffness to the system. It =
physically
restricts the motion of the bridge and that is quite another thing.) I =
have also
learned that -- assuming similar backscale lengths -- backscales =
terminating on
vertical hitchpins are less restrictive than are those terminating on =
the
conventional hitchpin/bearing bar arrangements.</FONT></DIV>
<DIV><FONT color=#000080></FONT> </DIV>
<DIV><FONT color=#000080>Del</FONT></DIV>
<DIV><FONT color=#000080></FONT> </DIV>
<DIV><FONT color=#000080>(PS A side note -- this is among the =
issues we
discuss in the Wednesday class given at the beginning of the Big =
Convention
which I have agreed to do at least one more time. The latest version of =
this
class will be presented this year in =
Chicago.)</FONT></DIV></BODY></HTML>