Bridge caps

[Ron Nossaman]

>I couldn't disagree more. This, FWIW, is also an unsupported speculation. We 
>are talking about a complex termination here, with the string contact on both 
>the surface of the bridge at a tangent point to the diameter of the string 
>and on the pin at a position above the bridge plane depending on the gauge of 
>wire and angle of pin. To say that the pin depth has nothing to do with 
>energy transfer is totally counterintuitive. 

It may be counterintuitive to you, but it makes mechanical sense to me. Any
pin depth beyond what it takes to hold the pin solidly is superfluous as to
energy transfer. What's the difference between not being able to push a
single story building over and not being to push a twenty story building
over? Other than failing against a more impressive obstacle, that is. It's
like the mistaken idea that soundboards must perfectly mate to the outer
rim or their energy will leak out. It just doesn't work that way. The glue
joint is the impedance termination for the soundboard like the friction on
the sides is the impedance termination of the bridge pin. I do like the
long pins because I think (but don't know) that they'll be tight in the
bridge for a longer time (lower psi load because the embedded area is
greater). They're also pointed, so I can install them easier. There is,
however, Del's point about bridge surface damage during installation.
There's also the point that the bridge surface won't push a string up and
down a short pin as far with humidity swings as it will a long pin, which
might very well result in less damage to the cap by string grooving. These
things considered, It may very well be that shorter pins can outperform
long pins in the long run. We pays our money and we takes our chance. None
of this, of course, has anything to do with how much pin is left sticking
out of the bridge, but I still can't come up with any reason that should be
critical to anything but strut clearance.



>any analysis of the Wapin structure would lead to impedance concerns. What 
>exactly impedance concerns, I can't say for sure yet, nor can they, but 
>obviously the decoupling effect of changing the angle of the bridge pin and 
>having a higher contact point on the pin with the string is causing a sustain 
>change, read impedance effect. 

I can't say either, but taking the pin to vertical *lowers* the contact
point of the string to the bridge pin, rather than raising it. That much is
certain. The tangent to the string is above center with a tilted bridge
pin. The consensus to date is that, being vertical and more rigid than the
bridge cap, the vertical pin steers the string excursion to horizontal,
rather than the elliptical path the usual configuration induces, and slows
energy transfer to the soundboard assembly by virtue of the string moving
perpendicular to the movement of the soundboard - making energy transfer
less efficient, and thus increasing sustain. Someone straighten me out here
if I've got it wrong.  


>To clarify myself (like butter?) a bit more, I 
>don't think we're talking about huge energy concerns here; minute ones at 
>best, but still energy transfer. 

Exactly my point. How minute is below the threshold of detection?


>Aside from intuition, my real experience has 
>been that deeply driven, bottomed, and least expose pin top structures have 
>greater clarity of tone production than any with these and other variables 
>not in evidence. I can only go on what experience has been proving to me time 
>and time again as we try to get better at what we do. 

By all means. Let's make 'em as good as we can. I'm just trying to separate
the physics from the mythology. What can I say, I'm anal. I like real world
cause and effect relationships that don't require faith or intuition for
acceptance. When we can figure out how the last thing actually worked, we
greatly improve our chances with the next thing. That's what I want.

Looking for the real stuff.

Ron N