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I have been thinking about what needs to be considered when selection the type of brace wood in relation to the top; besides the normal stuff like QS, no run etc.... Maybe its not an issue, but I wondered if some brace wood type is more desirable with certain tops say: WRC bracing on WRC or maybe its better to mix it up: WRC with sitka or Adi? Is it best to stay with the same wood or are dissimilar woods better? Is strength the only thing to shoot for or does the selection of these woods have an impact on tone? What about yellow cedar bracing and doug fir? What are things that you consider along these lines?

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Mark Ewing
Columbus Ohio
"Trees are an important and precious thing. We should build good things with them. Building good guitars with heart are the best use for them." K. Yairi.

I'm also looking forward to answers on this. Does the tonal character of different woods show through in bracing material similarly to how it does in the plates, or is the only appreciable difference the added mass to achieve the same stiffness? My instinct is that each would have its own character, and you could get different but good results with various combinations of plate and brace wood.

Along the same lines, what is the logic behind some guitars using mahogany or Spanish cedar for back bracing? Does the greater cross-grain stiffness compared to spruce benefit the back's stability, or is it related to expansion/contraction with moisture, or something else?

Has anyone ever braced a top with mahogany just to see what would happen?

Stiffness to weight ratio and ease of carving with planes and chisels along with all the normal things like runout,quarter sawn etc. I'm open to any differance created by using specific woods together but don't think it much of an issue and not a concern for myself.
Tom

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[quote="westca"]Stiffness to weight ratio and ease of carving with planes and chisels along with all the normal things like runout,quarter sawn etc. I'm open to any differance created by using specific woods together but don't think it much of an issue and not a concern for myself.
Tom[/quote

Top plate produce different tone quality. My thinking is the bracing would have a broader effect then simple structural. I suppose a builder would have to experiment with the different combination's of bracing/top mixtures considering the stiffness and weight factors. Light top plate with bracing at the high end of structural benefits. I guess my guy tells me that the brace material type, like top plate material, plays a part. I sure we all agree that layout and size are a factor but, are there other things to consider.
I have three rims built. All OM. Two walnut and one mahogany. I have a sitka, doug fir, and WRC, and engleman spruce boards to make tops out of. I have DF, WRC, sitka, and yellow cedar brace stock. What would you do? Mix and match? Match straight up? How would you approach the wood selection process. Feels like a crap shoot to me.

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Mark Ewing
Columbus Ohio
"Trees are an important and precious thing. We should build good things with them. Building good guitars with heart are the best use for them." K. Yairi.

If you weigh your top before and after bracing (with braces carved, tuned and cleaned up) you'll see that the weight of the braces/bridgeplate is virtually nothing compared to the weight of the top.
I suppose that any rational builder will look for bracing that has the best stiffness-to-weight ratio and the best resistance to splitting. WRC falls short on the latter, it doesn't mean it can't be used. But why?
I use red spruce 99% of the time, and have used sitka a few times. They both have similar advantages, except I find red spruce smells better and carves more readily.
I failed to distinguish a difference in tonal character between the two BTW. Like glue, it must theoretically have an effect on tone, however infinitesimal, but it seems easily dwarfed by any other minute detail of a build.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

From an old post, but I found Grumpy's comment especially helpful. http://www.luthiersforum.com/forum/viewtopic.php?f=10102&t=13786&hilit=mario

You guys are overthinking this. There are no magical synergies known to exist between top and brace woods.

But I would not use red cedar for bracing. It splits too easily. Spruce works nicely.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

I agree that in most cases spruce is the wood for the top. I have used red , Sitka , Engelman and even wood off an old 2 by 4 in my early days. I don't like mahogany , tried it once and won't bother ever again.
I would be more concerned that my joinery was perfect.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

The only magic, at least for me is somewhere between hard work, and dumb luck. It's a moving target It doesn't have alot to do with the actual species.

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I think it would really be helpful if people would try to make 'matched pairs' of guitars once in a while. Get two sets of the 'the same' wood, cut in flitch, and make everything as much alike as you can. Then see if they really sound the same when you get done. Until you can make 'identical' instruments reliably there's no way you can confidently attribute small differences to any such change.

Amen!
Three matched oak parlors coming up...

If I was going to make matched guitars, I certainly wouldn't 'waste' the variable on brace material

So now, according to you, Howard, I can no longer use "magical synergies" as a selling point?

Dang!

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I'm still curious on mahogany back braces.

And if softwood species don't make any appreciable difference on tone, what then would be the effect if you take it further and do a mahogany braced top? I'd guess a little dull and not as loud, but you never know, it might have a pleasing tone despite that.
Or how about ebony braces I just hate it, not even knowing what happens as you go toward extremes. But I guess spruce is probably close to ideal, and any experiments would just lead back to using it 90% of the time anyway.

alexanderlou3 wrote:
"If I was going to make matched guitars, I certainly wouldn't 'waste' the variable on brace material"

No, I mean _matched_, with no deliberate variables. I've found it surprisingly hard to make two of 'the same' guitars, and until you can do that, there's no sense in talking about the subtle differences you get from small changes. If you can't make a 'control' then where's the 'experiment'?

The only other way to go about it (and it's better in some ways) is to make one instrument that you can alter in some key way. That's what I did with my 'corker' to look at the variable of side ports. you can't really do that with bracing, though.

I use laminated spruce/RW braces on backs and some tops too. Sure it works. It' all a matter of figuring it out. You can't make one guitar with X or Y and quit.

I meant matched in that way as well, but to clarify further; I meant if I go to the trouble to build two nearly identical guitars then the one variable I'd change between the two probably wouldn't be on something as small as brace material. To me there's so many other things worth experimenting on that would have more effect towards tone.

edit: The corker was awesome!!! A great achievement Alan! Your post also reminds me that when I make an archtop type guitar I'm going to make a point to try out several styles of bridge shapes and sizes since they'll be easily interchangable. If only other things were too this art might not be such a mystery