Larrivee bracing

[SitkaSam]

Where can I find an illustration of Larrivee bracing? Can anyone explain the symmetrical bracing? On a traditional flat top, e.g. a Martin, the tone bars are assymmetric: closer to the end block on the bass side, closer to the bridge on the treble side. I assume the assymmetry enhances the frequency response of the top. Or not?? Am I over-thinking this?

[Zohn]

Hi SitkaSam, and  

The arrangement of the tone bars around the "X" of the bracing is symmetrical, meaning the configuration of the bracing is the same or "neutral" for left handed as right handed guitars.
As for "regular" braced guitars, the tone bars are asymmetric as you explained and oriented in a mirror image specific for left or right handers. The arrangement of the 2 legs of the X-brace is still symmetrical, although the shape sometimes differ in that the bass-side leg is sometimes more scalloped than the treble leg. The tone bars are arranged assymetrical between the legs of the X and behind the bridge plate.
Larrivee braces aren't scalloped but parabolic-ally shaped. (2nd pic)

The last pic is of a (scalloped) Martin OM's top






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[sgarnett]

Btw, the Larrivee SD's X braces ARE scalloped. However, the scalloping reduces the width of the brace, while Martin's scalloping reduces the height. Both approaches reduce mass, but they are very different structurally.

[GA-ME]

Btw, the Larrivee SD's X braces ARE scalloped. However, the scalloping reduces the width of the brace, while Martin's scalloping reduces the height. Both approaches reduce mass, but they are very different structurally.

I think you are confused about what "scalloped" brace means. Larrivee doesn't do scalloped braces.

[harley45jaap]

is the mixture of different metals including aluminum?

[sgarnett]

I think you are confused about what "scalloped" brace means. Larrivee doesn't do scalloped braces.

No, I am not confused at all. I agree that I've never seen it on any other Larrivee EXCEPT the SD-03 (which I purchased new). I also agree that it is different from Martin scalloping, but I think I already said that.

[GA-ME]

No, I am not confused at all. I agree that I've never seen it on any other Larrivee EXCEPT the SD-03 (which I purchased new). I also agree that it is different from Martin scalloping, but I think I already said that.

Could you explain what you mean by scalloped, in regards to the bracing on the SD 03?

[hadden]

Scallop means the scoop out of the lower half of the x brace and tone bars of the Martin pic above. I don't know any stock Larrivees with that. I assume there's a different word for thinning a brace from the sides.

[Denis]

Scallop means the scoop out of the lower half of the x brace and tone bars of the Martin pic above. I don't know any stock Larrivees with that. I assume there's a different word for thinning a brace from the sides.

Parabolic is the word used for the Larrivee bracing.  Is it not?  This means the braces are thinned out to a sharper point at the top?

[hadden]

Parabolic is the word used for the Larrivee bracing.  Is it not?  This means the braces are thinned out to a sharper point at the top?

That's what I think of as parabolic, when you look at the brace from the profile it has an arc. So yeah that sounds like the right term for side thinning. Larrivees don't have this though. I'm not sure what they mean by parabolic. If you sanded the edges off the x bracing they would be parabolic.

[jeremy3220]

Both 'scalloped' and 'parabolic' are buzz words in the guitar industry that don't exactly adhere to the strict definition of the actual word. Parabolic has been used to describe anything that is arched. I think Larrivee is referring to the lengthwise profile. It's really not a very useful term, it only gives you very general info about the bracing

[hadden]

Parabolic is the word used for the Larrivee bracing.  Is it not?  This means the braces are thinned out to a sharper point at the top?

from Jeremy's post you must have meant lengthwise. From upper bout to lower the length of the brace forms an arc. I wasn't sure what you were referring to by sharper point.

[rockstar_not]

Bracing, by whatever method, will affect the mode shapes of the top of the guitar.  These are the vibration patterns set up by imparting vibration into the top through the bridge.  Here's some pictures of the mode shapes of guitar tops:  http://www.guitarengineer.com/index_files/Page2109.htm

As with all things dealing with vibration, the stiffness and mass and damping characteristics of the materials, build construction and so forth affect these mode shape frequencies and strength - which in the end affect the radiated sound from the top of the guitar.

Now, if you think that it's easy to assemble all of that together to predict the tone a guitar will make - then you need to give it a go and try to compete with Mr. Larrivee and company.

Here's another discussion on this at AGF with some interesting videos of the mode shapes as well.

-Scott

[sgarnett]

Scalloping is making semi-circular cutouts in the edge of something. That is paraphrased from the 4th definition in my Oxford American English dictionary (they called it ornamental, but that doesn't apply in this context).

To make a scalloped Martin brace, you start with brace that has been shaped. Then use a sharp chisel with the edge parallel to the top to make semi-circular, concave cutouts. The result sort of looks like a suspension bridge.

To make the SD scalloped bracing, you start with the normal Larrivee parabolic bracing that has already been shaped. Then use a sharp chisel to make semi-circular concave cutouts   The difference is, the cutting edge is NOT held parallel to the top. It is rotated (let's say somewhere around 45 to 60 degrees).  The result looks sort of like the "coke bottle" fuselage of a fighter jet.

I have never seen the semi-circular cutouts in the braces of any other Larrivee. It is not Martin-style scalloping, but it is also not normal Larrivee parabolic bracing (though it begins as the parabolic bracing).

I bought my SD-03 new and unaltered except for a normal setup job.

[hadden]

To make the SD scalloped bracing, you start with the normal Larrivee parabolic bracing that has already been shaped. Then use a sharp chisel to make semi-circular concave cutouts   The difference is, the cutting edge is NOT held parallel to the top. It is rotated (let's say somewhere around 45 to 60 degrees).  The result looks sort of like the "coke bottle" fuselage of a fighter jet.

I have never seen the semi-circular cutouts in the braces of any other Larrivee. It is not Martin-style scalloping, but it is also not normal Larrivee parabolic bracing (though it begins as the parabolic bracing).

I bought my SD-03 new and unaltered except for a normal setup job.

My L-03 has what you describe in the upper half of the x brace.

[sgarnett]

My Forum I is sanded a little more in the middle of the upper legs. On the SD it's a lot deeper, and looks like it was carved.

[hadden]

My Forum I is sanded a little more in the middle of the upper legs. On the SD it's a lot deeper, and looks like it was carved.

On mine it's carved chisled like the SD, sounds like. The top of the brace almost comes to a point. I've forgotten who but someone recently posted a pic of their custum build Larrivee with the same cut.

[djacoustics]

Btw, the Larrivee SD's X braces ARE scalloped. However, the scalloping reduces the width of the brace, while Martin's scalloping reduces the height. Both approaches reduce mass, but they are very different structurally.

You got it rite except what larivee does is usually called "profiling" The end result is a brace with reduced mass but equal strength. A typical Martin type brace is both scalloped (material removed from the top of brace), & in some cases profiled (material removed from the sides of braces).

From the experimenting i've done scalloping reduced the stiffness of the brace, while profiling a brace causes little if any  change in stiffness, but does reduce mass. IMHO both techniques both shoud be employed in voicing the top & back plates.

[carruth]

Interesting thead.