Official Luthiers Forum!

I have a question about the purpose of soundhole braces. Are they just to reinforce the area around the soundhole, and to keep it from deforming? If so, it would seem that some 1/8" material, laid flat, would suffice. But if they are supposed to lend some other type of structural support (helping counteract the string tension, for example), then I suppose that they should stand up vertically, and be maybe 1/4" or so tall. It would seem to me to be the former, and that you could go pretty lightweight.

Instead of the 'what they should look like', I guess that I'm most curious about the 'why'. If I know how they are supposed to function, then I can feel more free to experiment and create.

Thanks for info and opinions,
Ken

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Ken Mitchell
Durham, NC

this is the type of question where a definitive answer may be elusive, all I can say is I have seen it both ways .jody

Jody,
Yeah, I've seen pics of both also.

Oh well, alea jacta est... I'm gluing some flat pieces in the L-00 I'm working on. If it explodes when I string it up, I'll come back and reconsider these little pieces!

Ken

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Ken Mitchell
Durham, NC

Ken it depends entirely on what you are trying to accomplish with your bracing.

If you look at Wes's very cool guitar in the current thread where he is asking for critique you will see that he uses A-frame bracing. In this case the idea is to distribute the load from the neck block through the upper transverse brace and eventually to the X-brace. This is intended to belay or prevent upper bout deformation.

The style that you see on many guitars where the sound hole supports are approx 1/4" wide and 1/8" high is intended to stiffen the sound hole area. You will also see iterations of this scheme where the sound hole supports are taller and shaped like braces.

The guys who use the flat sound hole supports are only trying to stiffen this area. Those using taller sound hole supports are again trying to stiffen but perhaps they see some tone potential here too.

Then there is Lowden where he doubles the material around the sound hole to stiffen this area and uses an A-frame too.

So IMHO it all depends on if the builder is addressing structural concerns and seeking to milk tone out of the sound hole area or if the builder sees these braces as stiffeners only. You will find many in both camps. And as with all things in guitar building there are probably more then two camps here too.

I used flats pieces/stiffeners on my 2 L-OOs and no explosions yet..... If memory serves me correctly this is what Gibson did too.

Hesh, thanks for all of that. With you and Gibson doing it this way, I'm thinking I'm in pretty good company

Ken

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Ken Mitchell
Durham, NC

I have used 1/4 wide or so by 1/8 high soundhole reinforcements on almost 100 guitars .... larrivee has done it on tens of thousands .... no explosions yet.

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

My approach to those braces is to treat them as if they have no acoustic purpose. Their function is simply to prevent cracking caused by trauma (such as whacking your bottle of scotch against the soundhole on the way down). I think the best defense against cracking is a cross grain circle all the way around the soundhole, the same thickness as the top.

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David White, Toronto

"All my favourite singers can't sing."

I agree and will throw this out there too - I feel the same way about side supports, this is why I use tapes.

Hesh,
Speaking of side reinforcement tape, Iv'e seen it on guitars, but I've never read anything about it, or heard what people use. What do you use (brand, type, etc.). I've been using thinner and thinner strips of wood, which look nice, but take quite awhile to make / install.

TIA,
Ken

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Ken Mitchell
Durham, NC

Hi:

There is the other issue where the interior of the soundhole (with a full circle support) is shaped rather than rounded off. I have forgotten where I read this but the recommendation for acoustic reasons is to not round off the soundhole edge but rather angle it back from the top edge about 45 degrees.

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GEO
perpetual beginner

Ken my friend here is a link to a toot that I put together about using side tapes and Titebond.

http://luthiersforum.3element.com/forum/forum_posts.asp?TID=8545&%20amp;KW=%28pics%29#forumTop

Todd did a toot too for using hot hide glue with side tapes.

I use Wright's "bias tape" which can be found at any girly fabric store after disguising yourself and wearing dark glasses so as to be sure that no one recognizes you......

Thanks, Hesh. Very informative tutorial, and thread!

Ken

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Ken Mitchell
Durham, NC