Official Luthiers Forum!

So I went into Guitar Center today and saw a Breedlove demo sitting on the wall that had pretty much been cut in half to expose the guts of it and demo how the bridge is connected to the end block via a wood block and rod.
I don't understand how this helps the sound. Everything I have read and intuitively think I know about the sound says that the more the top can float free of interference the better off the top will sound.
Any thoughts on this system?
-j.

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“If God dwells inside us like some people say, I sure hope He likes enchiladas, because that's what He's getting”
-jack handy

Is it like this:

http://www.stewmac.com/shop/Tools/Special_tools_for:_Bridges /JLD_Bridge_Doctor.html

The Bridge Doctor has been around a while, and it's primary purpose is to prevent the top from bellying at the bridge. My dad built a 12-string with one, and it is very effective.

As far as tone, the Stew Mac site says that "Better bridge contact and alignment can also enhance sound projection." I'm not sure what that means. "Better bridge contact?" I guess if the bridge was only loosely mounted to the soundboard before, and then you screw it down as part of the bridge doctor apparatus, I suppose that would improve contact and tone, but a properly attached bridge won't have "more contact" just because you screw it into a bridge doctor. Better "alignment" also sounds fishy. I suppose if you have a bellied bridge, that would arguably reduce the string break angle slightly, which I suppose could decrease tone, but not much. I have to believe that the minor sound advantages are outweighed by the disadvantage of connecting a weighty block of wood to the middle of the soundboard.

With that said, my dad's 12-string sounds good notwithstanding the weight of the bridge doctor, but probably not because of it. I would use it only to avoid bellying, not to enhance tone, though.

Of course, Breedlove probably has to sell it by talking about tone rather than structural advantages. It's not good advertising to say "We attach a clunky wooden apparatus to our guitars that no one else does because if we don't the top might belly at the bridge." Saying "it sounds better" will appeal to buyers more, even if it is a suspect claim.

This is a Bridge Doctor . I personally use them on a cheap guitar for a brige that rotates. They don't do a thing for the sound to help it. Added mass isn't a good thing on tops.
   

That's the JLD Bridge System, AKA "Bridge Doctor". They are sold as a remedy for 'bellied tops', where there is a hump in back of the bridge, and a sunken area in front of the bridge, and the bridge tilts foreward. The gizmo is a simple fulcrum designed to level the bridge & top. StewMac sells them for about $20. There is 'some discussion' that it also improves sound, and a few makers like Breedlove and Trinity build them into their new guitars. Google "JLD Bridge System", or "Bridge Doctor" for more details. I've got a 70's Martin/Sigma 12 string with a bellied top that I plan to 'Bridge Doctor'.

CrowDuck

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Chris Nielsen
Soquel, CA.

JLD Bridge on the Breedlove

I played a few at GC last weekend.. I wasn't impressed.

[QUOTE=j.Brown]
I don't understand how this helps the sound.[/QUOTE]
It generally, from what I've heard, doesn't. Actually, there are two models, each with differing attachment methods: The Bridge Doctor is designed to retrofit to existing guitars, and may, in fact, help the sound of a top that has begun to look like a potato chip; but I don't know for sure, 'cause I've never heard a before-and-after instrument. The other model is promoted as "original equipment," and is supposed to transfer some of the top stresses to the tailblock, thus preventing buckling as time passes. Breedlove claims that this allows them to "free" the top by removing mass from the braces, prompting better soundboard vibration. In my subjective opinion, it doesn't enhance the sound. In fact, the Breedloves I've played have all sounded pinched and restricted. But, you know, they're distinctive and well-constructed, and if they sound good to you, they are good!

Breedlove is not the only luthier who builds this way. David Hurd uses his own variation of the idea in certain models of his ukuleles.

Actually there's a huge amount of material on his site that ought to be of interest to those who wonder how these wooden things with strings work.

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D..

    The Bridge Doctor can signifigantly improve sound when used during the original construction of a guitar. If installed aftermerket as a solution to a problem, it is very effective, but sound is usually not affected in a noticeable way. most problems arise as the result of poor or incorrect installation or adjustment.

   If the intention of using a Bridge Doctor is present while designing a guitar and building it, the top can be braced much more lithely or lightly to work in conjunction with the added stability and benefits of the the unit being installed. With its ability to resist the torque of the bridge under string tension and its tendency to pull the top into the bellying distortion that is so common on some guitars, the braces don't have to be as heavy or able to bear the entire load themselves. The bridge plate can also be lighter and thinner when the Bridge Doctor is a consideration during the construction process.

   Breedlove guitars are very nice sounding and very responsive with the Bridge Doctor installed from the factory so you can't argue with success. Those who have only used guitars that have had them added to alleviate top distortion aren't in a position to make a call on the unit's effectiveness on the Breedlove models that employ it since they're pulling apples and oranges comparisons from two completely different scenarios. You don't want to go by what you've heard or read or seen from aftermarket installs, but go by the great results that are being achieved by the guys at Breedlove as they design and build guitars with theuse if a Bridge Doctor in mind from the drawing table.

   As far as added mass to the top goes, the unit is made from quartersawn Spruce and is very light in weight and the contact made with the top is minimal and very solid so it becomes almost integral with the top itself if installed properly and set up correctly.

Regards,
Kevin Gallagher

I would imagine that the Bridge Doctor would act similarly to the way a sound post in a violin, bass, or cello does. Sound posts are used to tranfer the vibration of the string through the bridge into the post and into the body creating a more resonate sound.

-Bill<><wbock38806.546875