Bridge Seating / food for thought

[Ric Brekne]

Hi folks

I just thought I might throw some numbers around to look closer 
math-wise at this idea that the wobbly pin can change the speaking 
length enough to account for false beats.  Take the following wire.

0.9 mm diameter and 150 mm speaking length at a starting tension of 
150.95  lbs This yields a frequency of  1218.93 Hz.

To get a  rougly 4 beat per second false beat this string needs to 
change in length by  around 0.003 mm.   That would require the pin to 
deflect  nearly 1 mm !!

It would take a 0.15 mm pin deflection to enable a 1 bps false beat.

Realistically a pin might be able to wobble say 0.02 mm. That would 
yield only a 0.15 Hz change.  Not hearable really. On shorter strings 
the change would be slightly (and I mean slightly) greater.  On longer 
strings, less.

Seems to me that  it is obvious that  the pin can not wobble enough to 
change the length and tension of the string enough to cause any false 
beats at all. 

There are other problems with this whole idea of wobbly pins causing 
false beats.. such as the frequency of the supposed wobble itself... why 
the significant side bearing hasn't already pushed the pin as far 
sideways as is possible.... etc etc.. but the above in itself should be 
enough to discard the idea.

Cheers
RicB