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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=Erwinspiano@AOL.COM
href="mailto:Erwinspiano@AOL.COM">Erwinspiano@AOL.COM</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A =
title=pianotech@ptg.org
href="mailto:pianotech@ptg.org">pianotech@ptg.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> November 29, 2001 6:54 =
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> sanderson Bass
strings/scale</DIV>
<DIV><FONT color=#000080></FONT><FONT color=#000080></FONT><FONT
color=#000080></FONT><BR></DIV>
<DIV><FONT face=arial,helvetica><FONT size=2><FONT face="Lucida =
Sans"
color=#000080 size=3></FONT><FONT face="Lucida Sans" =
color=#000080
size=3></FONT><BR> Having too much tension in a bass =
scale will
choke the sustain in any piano. Having too much tension in the bass or =
treble cannot only change the tone color but choke it as well.
<BR> When I spoke at length with his shop foreman he said =
that the
wire size on noter 88 had gone from a no.13 to a 14 size wire. That's =
a huge
jump in tension. The 2 top trebles apparently received this same whole =
size
increase and was the most choked in both pianos. <BR> I =
explained
to them , as Del and Rons have stated many times, that a rib scale is =
designed
for a particular string scale. Yes, it is possible to make string =
scale
changes on an existing board. Many of us have done it but, if the =
tension
changes are too great the tone and sustain will be altered in a =
negative way
,ask me how I know. Scaling is a wonderful tool but some =
times
it's better not to mess with success and the stwy O doesn't , =
I.M.H.O.,need
drastic changes in the stringing
scale. </FONT></FONT></DIV></BLOCKQUOTE>
<DIV><FONT color=#000080>While it is true that the stringing scale and =
the
soundboard/rib scale should 'match,' within the parameters of an =
existing piano
like the Model O, the stringing scale requirements aren't going to =
change all
that much between a compression-crowned soundboard and a rib-crowned =
soundboard.
At least not if you're sticking to the original rib dispersion. In terms =
of
overall tension you're going to be limited more by the structural
characteristics of the plate. At least you should be. Depending on the
characteristics of the specific piano, the Model O will have about 5,700 =
to
5,900 kgf (approx. 12,500 to 13,000 lbs) of string tension through the =
tenor
section. Now, this ranges from a low of about 52.2 kgf (approx. 115 lbs) =
to a
high of about 77.2 kgf (approx. 170 lbs) and it can certainly stand to =
be evened
out. But, when you're all finished with your nice new scale, you =
shouldn't be
all that far from the overall stress level the plate had on it =
originally. You
can generally get by with increasing things a bit through the top two =
sections
since most plates are considerably over-designed (on purpose) up there
but It's best to be some cautious through the bass and tenor. =
</FONT></DIV>
<DIV><FONT color=#000080></FONT> </DIV>
<DIV><FONT color=#000080>I know nothing of Sanderson's scaling =
priorities, but I
have looked at one or two Steinway scales over the years. As you point =
out,
there is no single Model O scale. It varies with the piano. In general,
however, the Model O has a relatively low tension scale. This is =
especially
true in the top section. It is a scale that can, indeed, stand some =
improvement.
In my computer I have Model O scales with C-88 as short as 45 mm and as =
long as
50 mm. In my opinion, all of these are too short; hence, the tensions =
will be
lower than I would like.</FONT></DIV>
<DIV><FONT color=#000080></FONT> </DIV>
<DIV><FONT color=#000080>However, putting fat strings on an
excessively short scale is not the solution. I have tried scaling =
these
starting with #13 1/2 wire at C-88, but wasn't really satisfied with the =
results, especially on those pianos with shorter speaking lengths. No, =
it's not
just the tension and it's certainly not the inharmonicity. This wire is =
simply
too stiff for the lengths of these short strings. The pretty, straight =
line in
the graph does not necessarily translate into musicality. </FONT></DIV>
<DIV><FONT color=#000080></FONT> </DIV>
<DIV><FONT color=#000080>There are two possible solutions for these =
scales that
do work. The first, and easiest, is to simply remount the bridge back =
slightly,
giving a C-88 speaking length of 52 mm. This will also increase the =
length of
the rest of the tenor strings but, of course, this is also desirable =
through the
top two sections. (That whole top section is really quite short.) The =
additional
length won't have much effect through the tenor section. In some pianos =
this may
require a bit of grinding on the plate hitchpin panel up toward the top
longitudinal strut. </FONT></DIV>
<DIV><FONT color=#000080></FONT> </DIV>
<DIV><FONT color=#000080>The second, and more difficult, is to make a =
new treble
bridge, setting C-88 to 52 mm and laying out the rest to a log pattern =
through
the top two sections. (Since it is not possible to end up with a true
logarithmic scale in most of these pianos, I call this a =
<EM>SemiLog</EM>[tm],
or <EM>S/Log</EM>[tm], scale.) This will lengthen all of the strings =
through
these sections and will greatly improve the tonal performance through =
the killer
octave region as well as through the upper treble section. Even with a =
softer
hammer both sustain and power will be improved. This will definitely =
require
some grinding on the plate, though not enough to effect its strength in =
any way.
</FONT></DIV>
<DIV><FONT color=#000080></FONT> </DIV>
<DIV><FONT color=#000080>Obviously, in both cases it will be necessary =
to either
relocate or replace the back aliquot bearing bars. I don't consider this =
to be a
problem, others might. I am happy enough with the improvement in =
performance to
not worry about the loss of a questionable feature. </FONT></DIV>
<DIV><FONT color=#000080></FONT> </DIV>
<DIV><FONT color=#000080></FONT> </DIV>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000080 2px solid; MARGIN-RIGHT: 0px">
<DIV><FONT face=arial,helvetica><FONT size=2> I have been =
routinely
rotating the top of the bridge back when installing a new board to =
accommodate
a speaking length of 2". This small change makes a modest increase in =
tension
using the original scale and improves power and projection in the top =
octave
or so. </FONT></FONT></DIV></BLOCKQUOTE>
<DIV><FONT color=#000080>As per option 1, above. This certainly helps, =
but I
found that the real problem was the first octave in that top =
section. Hence
the switch to a new <EM>S/Log</EM> bridge.</FONT></DIV>
<DIV><FONT face=arial,helvetica><FONT size=2><FONT face="Lucida =
Sans"
color=#000080 size=3></FONT></FONT></FONT> </DIV>
<DIV><FONT face=arial,helvetica><FONT size=2><FONT face="Lucida =
Sans"
color=#000080 size=3></FONT> </DIV>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000080 2px solid; MARGIN-RIGHT: 0px">
<DIV> All that to say that changing to higher scale =
tension in
this case had a compounding negative consequence because of the =
excessive
tension of the new Sanderson scale. </DIV></BLOCKQUOTE>
<DIV><FONT face="Lucida Sans" color=#000080 size=3>As I said =
above, I don't know
anything about Sanderson's scaling philosophy, but I suspect there is =
more to
this than higher scale tensions. Folks dabbling in piano rescaling often =
tend to
focus on one or two parameters and sometimes overlook the big picture. =
For many
years I refused to give classes on 'rescaling' because the principles =
were so
often mis-used. In this case, even though the numbers in the spreadsheet =
looked
good, length/diameter ratio is going to pretty low.</FONT></DIV>
<DIV><FONT face="Lucida Sans" color=#000080 =
size=3></FONT> </DIV>
<DIV><FONT face="Lucida Sans" color=#000080 =
size=3></FONT> </DIV>
<DIV><FONT face="Lucida Sans" color=#000080 =
size=3></FONT> </DIV><FONT
face="Lucida Sans" color=#000080 size=3></FONT>
<DIV
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000080 2px solid; MARGIN-RIGHT: 0px">
Anyway a cut to the chase. The client restrung both "o"s with mapes Bass =
strings
and original scales. The sustain , power and sonority returned . =
>From what
I understand the client had a discussion with Dave S. who was =
Quote rude
and unprofessional. He did however agree to refund his money for =
strings. But
wow the loss of time and labor cost. My client said that this was =
obviously Not
the first time that Mr. S. has received these complaints =
<BR> Is this
anybody else's experience? </DIV>
<DIV
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000080 2px solid; MARGIN-RIGHT: 0px"><FONT
face="Lucida Sans" color=#000080 size=3></FONT> </DIV>
<DIV><FONT face="Lucida Sans" color=#000080 =
size=3></FONT> </DIV>
<DIV><FONT face="Lucida Sans" color=#000080 size=3>Scaling by =
remote control can
be a tricky thing. While I do some rescaling work and redesign work =
for
other rebuilders, I really do prefer to know the person I'm working =
with. While
most of my experiences have been good, there is always the odd =
exception. It is
very easy to mis-judge technical capabilities and expectations. =
</FONT></DIV>
<DIV><FONT face="Lucida Sans" color=#000080 =
size=3></FONT> </DIV>
<DIV><FONT face="Lucida Sans" color=#000080 size=3>The scale I'd =
recommend for
an O with an original soundboard and bridge is not the same one I'd =
recommend
for an O with a new board and a relocated bridge. </FONT></DIV>
<DIV><FONT face="Lucida Sans" color=#000080 =
size=3></FONT> </DIV>
<DIV><FONT face="Lucida Sans" color=#000080
size=3>Del</FONT></DIV></FONT></FONT></BODY></HTML>