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<DIV><SPAN class=031142411-22082004><FONT face=Verdana =
color=#0000ff size=2>Hi
Sarah,</FONT></SPAN></DIV>
<DIV><SPAN class=031142411-22082004><FONT face=Verdana =
color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=031142411-22082004><FONT face=Verdana =
color=#0000ff size=2>As
usual, another thought provoking letter. </FONT></SPAN></DIV>
<DIV><SPAN class=031142411-22082004><FONT face=Verdana =
color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=031142411-22082004><FONT face=Verdana =
color=#0000ff size=2>It
is Sunday morning, not the best time for thinking, and I majored in =
phys.
ed.(dumb jock), not math, but I will give it a shot.</FONT></SPAN></DIV>
<DIV><SPAN class=031142411-22082004><FONT face=Verdana =
color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=031142411-22082004><FONT face=Verdana =
color=#0000ff
size=2>Hammer felt density increases from bass to treble. In a perfect =
world,
the density of the wood will be the same from hammer to hammer. However, =
since
moldings are made from strips of wood glued together, probably from =
different
trees, this is not the case. This would account for weight differences =
from one
molding(tree A) to the next(tree B). Different types of wood are =
used to
make hammer moldings. We use silver maple, sapele, or hard maple. Other =
types of
woods are used by other manufacturers. Hard maple is denser than hammer =
felt,
while silver maple is not. Hammer felt gets thinner from bass to treble, =
as do
hammer moldings, so that, ideally, as you go up the scale, each hammer =
will be
lighter than the previous hammer. Since it is not a perfect world, we =
have you
guys to save the day. Hope I gave you some useful information. Probably =
should
have waited until my brain if functioning better, but that won't be till =
...</FONT></SPAN></DIV>
<DIV><SPAN class=031142411-22082004><FONT face=Verdana =
color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=031142411-22082004><FONT face=Verdana =
color=#0000ff size=2>Ray
Negron</FONT></SPAN></DIV>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
<DIV class=OutlookMessageHeader 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>Sarah
Fox<BR><B>Sent:</B> Sunday, August 22, 2004 12:31 AM<BR><B>To:</B>
Pianotech<BR><B>Subject:</B> SW heresy?<BR><BR></FONT></DIV>
<DIV><FONT face=Arial size=2>Hi all,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Thanks for the advice about =
techniques to even
out the SW curve! That should give me a variety of techniques to =
use/combine in order to even out the jags.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>But the question is one of what my =
target curve
should *really* be. Hmmmm.... My thoughts:</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The unmodified SW curve is =
obviously
very linear. (Yes, I know what linear means. I =
"minored" in
mathematics, sort of -- except that my U. didn't officially recognize
minors). Stanwood's curves, OTOH, are all concave
downwards.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I was advised off list that I =
shouldn't force the
hammers to artificially conform to a standardized Stanwood curve but =
to simply
even out the jags to make the action smooth from bottom to top. =
There's
something to be said for this idea.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>But as I got to thinking about the SW =
curves, I
was wondering, where do they REALLY come from? That is, where =
does the
shape come from? I suspect the hammer manufacturing people might =
be able
to enlighten me as to this. (Ray???) I'm *guessing* that =
the felt
is denser than the molding, and when the hammer becomes skinnier, it =
loses
more felt than molding, resulting in a more precipitous dropoff =
in weight
at the higher end. This would occur with a constant hammer =
length and a
linear variation in hammer and molding (and felt) width. Am I =
anywhere
close on this idea???</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Contrast this function with other =
functions that
might actually relate to optimal hammer mass: String length and =
mass
both decrease with the note number, with a function that is concave
upwards. Note frequency increases with a function that is =
concave
upwards. Note period (inverse of frequency) increases with a =
function
that is concave upwards. The Stanwood curve seems rather =
meaningless
with regard to any of these functions. For instance, it might be =
good to
match hammer mass to string mass by some proportion. =
Right? As the
scale goes up, string length and mass approach an asymptote of =
zero.
Therefore, shouldn't hammer mass approach an asymptote of zero? =
Instead,
the curve starts taking a dive in the treble. If the scale went =
up well
past 88, hammer mass would eventually crash to zero. Because =
these
curves do not have the same form, the relationship between hammer and =
string
mass is anything but constant. That doesn't make =
sense.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>So is this something that is the way =
it is just
because of tradition -- because the cauls are built that way, and =
that's what
ya' get? </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Now that I look at my linear SW curve =
(with
jags), I'm wondering if this isn't REALLY a closer match to something
meaningful (like string mass) than the idealized Stanwood =
curves. Any
thoughts, y'all?</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Peace,</FONT></DIV>
<DIV><FONT face=Arial size=2>Sarah</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial =
size=2></FONT> </DIV></BLOCKQUOTE></BODY></HTML>