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I’m building a guitar that I’ve built about 15 or more times, a small jumbo cutaway. I’ve always used what is basically a belly bridge. Has anyone done the same (built the same model with a belly bridge) and tried a smaller bridge to test the difference. I see all styles of guitars with small bridges - pyramid bridges or bellyless briges. Not sure what you call them, about an inch high by 6 long. I’m wandering what to expect tone wise. I should mention that my builds of the model all sound fairly similar. Thanks advance

I think I’d try messing with the weight of the bridge first. You aren’t specific about bridge material - if you have always used an ebony bridge, give rosewood a try and see what that does. The bridge in the pic is Royal Blackwood (torrefied Purple Heart) which weighs about the same as rosewood.

Cheers!

+1 as Michael suggested, try a different material first to see the changes. I just did this recently. I have built all guitars with ebony bridges and rosewood bridge plates. The last two dreds are maple bridge plates, one with ebony and one with rosewood bridges.

I’m 100% positive the changes in sound between the two are bridge related.

But they did sound different.


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I’m still a rosewood bridge plate guy. I was a cabinet maker for too many years and experienced the seasonal dimensional change in maple cabinet doors. The rosewood is more stable - I doubt I’d be able to hear the difference, kinda like me being able to hear the difference between nickel and SS frets…

If you really want to drop some weight in the bridge you can adopt Trevor Gore’s method of using a carbon fiber sandwich and a lighter species of timber than the traditional ebony or rosewood. We want the bridge to be really stiff, which is why ebony has been the traditional choice. It is very stiff, but also heavy. You can make a lighter piece of wood just as stiff as ebony if you make a wood-CF-wood sandwich. Trevor uses woods like Australian Blackwood, paduak, walnut and they can be half the weight of an ebony bridge. Some info on his website, and copious information in the Gore/Gilet design and build books.
https://goreguitars.com.au/innovation/

Anyone else focusing on bridge weight and material? A heavy bridge is a sure way to limit top mobility, and vice-versa.

Re-visiting the bridge mass and stiffness, I just read Trevor Gore's paper* that has a mention of bridge woods, relating to mass and stiffness. Trevor identified three woods that balanced stiffness, density and hardness: padauk (Pterocarpus sp.), walnut (Juglans nigra) and Tasmanian blackwood (Acacia melanoxylon). These are not particularly easy to find in a bridge blank sized chunk.

I may end up cutting my own bridge blanks from Black Walnut I harvested 15 years ago, and cut into boards.
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*161st Meeting Acoustical Society of America Seattle, Washington 23 - 27 May 2011 Session 3aMU: Musical Acoustics 3aMU4. Wood for Guitars


https://aipp.silverchair-cdn.com/aipp/c ... online.pdf

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Karl Borum

He lists the same three in his book.

Black Walnut is fairly easy to get here in California. 15 $/BF.

Other North American species with similar Janka hardness (so the strings don't cut through), density, and sound radiation coefficient are: Red Maple, Black Cherry.

The Ebonies and Rosewoods are all heavier and lower sound radiation.

Greg