false beats from ?? -...

[Ric Brekne]

Hi Don

Nice observations.  I remain increasingly skeptical to the idea that the 
pin somehow is moving around in the hole causing such a clean sounding 
false beat, for reasons I have already stated.  Too many inconsistencies 
with the idea.  The beast itself sounds more like a phasing problem and 
I suspect something more along the lines of an inconsistent transfer of 
energy from the string through the bridge assembly that has more to do 
with the wood in the bridge itself then any particular pin condition.

I think one of the roots of disagreements on this issue has to do with 
how various folks view the basic vibrational characteristics of the 
entire soundboard assembly. If one adheres to the idea that the 
soundboard and bridge assembly simply moves up and down and does 
absolutely nothing else of significance in response to the complex 
vibrations (both transverse and longitudinal) then perhaps it is easier 
to jump on the <<loose pin is moving>> idea.  That said one still has to 
adequately describe the mechanism this loose and moving pin causes such 
a clean sounding beat. And one has to describe how this beat can vary in 
speed. This might be just a tad difficult if the soundboard/bridge 
assembly effectively ignores any sideways or longitudinal string 
vibrations. I would just love to see some one try and actually measure 
any pin movement that could explain this.  The measurements should be 
doable for sure. Both from a methods and technological perspective.  But 
I'd be surprised at best if said would do anything else then confirm the 
loose pin hypothesis to be faulty.

Cheers
RicB

Don Rose writes:

If the cause of the false beat is the pin moving in the wood then CA serves
more than just one purpose. It tends to fill any gaps, it tends to fill and
voids, it tends to size the hole, AND it increases the density (hardness?)
of the wood.

If, on the other hand, it is a "wood problem" CA may help to reduce the
false beat--even if the pin appears to be "tight", because it may increase
the "firmness" in some manner.

This may also explain why Ric B. had no false beat results with "sloppy"
pins where he deliberately tried to "induce" a false beat. The wood was
"firm" and the side bearing was great enough to keep the pin "still"
against the "support" from the bridge, providing a "beat free" termination.

Why does the pin move? Because the support is insufficient.