bridge pin placement

[Ron Nossaman]

>We all know that bridge pins should bisect the bridge top-bridge notch 
>edge. I am finding myself a bit tongue-tied in trying to explain the exact 
>problems (and aural symptoms) that occur when this ideal is not met. I'm 
>not talking about a pin being way, way out on the notch, rather just 
>barely touching the edge (or vice versa). Anyone have a nice clear 
>explanation that will help me be more eloquent when trying to explain this 
>to a customer who has asked me to evaluate a new upright for his purchase?
>Thanks,
>Patrick Draine

Problem is, I'm not so sure there is a clear reason that this is 
undesirable. I know, we were all told it was because it established two 
different speaking lengths and caused beats. But does it? There are new 
pianos notched this way that have no hint of false beats. It was explained 
to us that the pin established the speaking length for the horizontal 
excursion, and the notch for the vertical. That's fine except for the small 
detail that the string doesn't slither up and down the string as it 
vibrates, at least not to the degree that produces false beats. It's 
clamped down by bearing and pin angle. The beat comes from a loose pin 
flagpoling horizontally, as indicated by stopping it's movement with a 
screwdriver or some other tool on the side of the pin opposite the string. 
If it was the notch making noise, anchoring the pin wouldn't change a 
thing, but it does. Too shallow a notch is a problem, but too deep 
typically is a problem only when the pin is loose.

Ron N