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Sorry if this seems like a simple question.

Why do classical guitars use the bridge that is glued to the top? Why don't they use something similiar to a violin? I mean the tail piece attached to the back and then the seperate bridge piece.billb38593.8209490741

The "why" part of your question is very difficult to answer directly but I'll give it a shot.

The classical guitar's lineage comes from plucked instruments (such as the Vihuela de Mano) rather than bowed instruments (such as the Violin or Cello). The predecessors to the traditional Torres design had this sort of bridge (though often without the removable saddle), and it interacts with the soundboard in an entirely different way than a violin bridge. If there was ever a definite reasoning for this type of bridge early on - I am unaware of it, but certainly the design of the soundboard has been adapted to work at its best with a glued on bridge.

With a violin style bridge the soundboard mainly has to deal with the string tension pushing down on the arch. With a glued bridge the soundboard has to deal with the twisting effect - the area behind the bridge gets pulled up while the area in front of the bridge pushes in, because of where the strings are attached and their bearing on the saddle.jfrench38593.8383564815

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Bilb,

Just to add a bit more --

This is indeed a complex subject. If you look at some plucked instruments -- most notably the mandolin and banjo -- you'll see that a violin-style bridge arrangement is capable of producing great output, rivaling that of a violin. But guitars are much larger and are asked to produce much greater bass response than mandos and banjos.

I've played quite a few archtop guitars. And as you know, they all have bridges that are similar to violin bridges in construction. Seems to me that they all share one more characteristic -- they really need to be amplified. So, why are guitars that use violin style bridges so quiet? Simple answer, I believe, is because they're not bowed. Hey if you pluck a violin or a cello, it isn't very loud, either. But set a bow to the strings, and the difference is profound. That's because a bow continually excites the strings, unlike the way a pick or fingers operate. They need this continuous excitement to make up for the fact that the force of the strings is being applied in only one direction -- the downward force across the bridge.

By gluing the bridge directly to the soundboard, a guitar's soundboard has two forces being applied to it instead of just one. A violin/cello/archtop has basically a single force being applied to its top -- a downward force caused by the angle of the strings as they travel over the bridge to the tailpiece. The shallower the angle, the less the tension. A classical (and steel string, for that matter) has the downward force caused by the break angle over the saddle, but because the strings terminate at the soundboard, the bridge gets into the act too. It contributes a front-to-back rocking motion when a string is plucked, which adds to the volume. In at least one test I've read on soundboard acoustics (Siminoff: _The Luthier's Handbook_), the claim is made that most of a guitar's volume comes from this rocking motion of the bridge.

I suspect that, way back in the dark and dim early days of the guitar -- back in the Renaissance era, even -- builders were figuring out that they would get better volume by gluing the bridge to the soundboard and anchoring the strings there. Just a guess, but hey, that's the way they've been built for four hundred years or so.

Best,

Michael

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Wow great. Thanks for clearing this question up guys.

Micheal. I had a feeling it had something to do with the fact that the violin is bowed. I know that banjos uses a similiar bridge, but I don't much about banjos.


Micheal Mcbroom quote:

It contributes a front-to-back rocking motion when a string is plucked, which adds to the volume. In at least one test I've read on soundboard acoustics (Siminoff: _The Luthier's Handbook_), the claim is made that most of a guitar's volume comes from this rocking motion of the bridge.

Reply:

Very interesting