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I've got 4 different body styles, small 'O' to 'OOOO' and have bracing set up for each but I neglected to increase the 'X' brace angle for the largest of the guitars. The bracing is installed, bridge plate in and I was beginning to carve and wanted to know the effect the angle had and that's when I discovered the 'X' angle is about 92 degrees for the largest OOOO guitar.

I've since learned that Martin uses 98 - 100 degrees (or there about) for their larger guitars and can get down to 90ish for the smaller guitars.

I've also learned that the 'X' angle can have quite a dramatic effect on the tone. Shallow more focused, perhaps more balanced, wider/deeper, more base.

My question is, I'm pretty much stuck with the bracing 'X' angle at the current 92 degrees so I was wondering what would you do differently when carving the braces? Deeper scallop? Lower 'X' joint? Less bracing all round? Top is medium stiff and currently at around .110.

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I've heard that it is as much about how the ends of the bridge intersect with the braces as it is with the angle of the "X". The braces crossing under the wings of the bridge help stabilize the top and keep the bridge from rotating. Depending on where they pass under the bridge can make that area more or less stiff.

Most probably accurate Clay but wouldn't you agree that 92 degrees is a bit shallow for that size guitar? No matter where that bridge crosses? Or is it more complex as you suggest? Anyone build a large body guitar with that shallow an 'X' brace angle?

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As you shift the "X" forward or back it will cross the bridge at different points. Where it crosses the bridge and the distance the junction of the "X" brace is in front of the bridge (the size of the "triangle" made by the braces and bridge) probably has a greater impact than the actual angle of the "X".

OK...but let's say the location of the 'X' doesn't change forward or back. What effect does the angle have then? Does a wider angle produce more bass like I've read? And is 92 degrees too tight? And if it is, is there any other bracing steps that might be taken to get it 'loosened' up?

There's really nothing I want to do to change the angle at this point so just wondering about some bracing philosophies re: the 'X' angle.

..and thanks very much for the reply - I appreciate it.

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I guess a tighter angle would produce a stiffer top lengthwise. You could accommodate that by lowering your x height a fraction. But really, since the whole thing is acting as a system, the small change in angle is not likely to be too terribly significant in itself alone. I would say follow your normal procedures and judge the result. It may be the bestest thing ever...

If you notice where the "X" braces are scalloped, it is very often in the area of the bridge plate. This may be one way you could loosen up the top if you find it is too stiff.
As long as you have enough space between the legs of the "X" for your bridge pins I wouldn't worry too much about it.

Thanks very much for the input. I'll carry on and see what appears. The top is indeed very stiff with bracing so I'll take a little off the 'X' and proceed.

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Larrivee has used a 90 degree X on about a half million guitars ... of all sizes

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

VERY much appreciate the info Tony.

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