Bridge feet contact area

[Bill James]

Different bridges have varying amounts of contact area depending on the size of the feet. I'm wondering about the effects this has on the movement of the top. Has anyone studied this and come to any findings?

I'm also curious about the effects the width of the bridge has.

[Marty Jacobson]

It sure has been studied, and pretty thoroughly. Poke around on the Internet for the research done by Kasha and Schneider, for starters. If memory fails me not, there's also a bit in annals of the Catgut Acoustical Society, among other places, on this subject.

Dr. Cohen does some pretty elegant things with the bridges on his mandolins, and from what I've heard, with both excellent theoretical and empirical credentials to back up his implementations. I believe he's rightly the foremost expert in this field with respect to mandolins at the moment. He should be able to point you to a preponderance of literature in a heartbeat.

The now-famous Red Henry Bridge thread in the Co-Mando archives deals with related issues, no doubt you're already familiar with the findings reached by the myriads of contributors to it.

Good luck with your experimentation, and by all means, if you find the Bridge from Elysium in your researches, pray enlighten our state of collective cluelessness.

[Michael Lewis]

Bill, there are too many variables to allow reaching a definitive conclusion other than that there are too many variables to allow reaching a definitive concluion. That being said, there are 'envelopes of function' for each variable. The ultimate bridge would be more efficient than what we have now, however, we seem to make do with what we have now. Some of the most effective variables are the width of the string contact area of the top of the saddle, the density of the effected parts, degree of damping in the material of the saddle, the stiffness (beam strength) of the saddle, the stiffness of the foot of the bridge, the stiffness of the top plate in the bridge area, string break angle, etc. Since the entire structure is involved in producing the sound, all the parts are interacting and interdependent. There just ain't no easy answer since each case is somewhat different.

[Bill James]

Thanks guys.

I would like to do some experimenting since I have a couple of theories on this. I'll look for the existing studies first so as not to re-invent the wheel, or bridge as it were.

Bill James