Bridge as a 2nd class lever

[Ric Brekne]

Hi Cy, I wasnt aware that Reyburns graphs touched directly on this 
particular perspective, but perhaps it does.  It might be interesting to 
see if his measurements show any correspondance to this bridge leverage 
idea.

As far as soundboard deflection having an measurable impact on pitch, I 
would have rather assumed that was a given in itself. Only stands to 
reason if the soundboard deflects one direction or the other even a 
little, then its pressure on the string will change yeilding a change in 
string tension.  The only question is how much deflection results in how 
much pitch change.  But it does strike me that if a change in downwards 
pressure anywhere on the bridge can/does effect change in downwards 
pressure at or around the killer octave region... then one should be 
able to directly measure this and that string tensions is a likely 
approach.  One doesnt necessarily need a <<major factor>> type pitch 
change... only one that is significant enough to observe by measurement. 

Course there are probably other ways of directly measuring the effect of 
changes in bearing on the bridge at other places on the bridge.  This 
was just the first that came to mind.

Cheers
RicB



 > Dean Reyburn has extensive graphs of the interactions of tension on the
 > bridge, that he used to put the pitch raise feature into RCT.  I assume
 > Robert Scott has similar data.  It may be proprietary to them, of course.
 >  
 >
 >> I'd like a much closer gander at the printouts and the assumptions
 >> made. As far as I understand there has been no attempt (outside of
 >> mine today) to actually measure in any way whether the model holds
 >> true ??  If someone knows otherwise please send along whatever info
 >> you have.
 >>
 >> Thanks for any and all comments
 >> Cheers
 >> RicB


All of which assumes that soundboard deflection is a major
factor in pitch change, evidence to the contrary. If you can
make that unsupported presumption work plausibly by either
demonstration or by math and logic, then you have a potential
case. Otherwise, you're just making random noise.
Ron N