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I was just wondering what type of bracing all of you guys use, and why. Have you built guitars using both styles of bracing, if so what differences did you notice between the two. This is a very interesting subject to me as great guitars are built with both types, but des one style dictate a different tonal range/character than the other?

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Gwaltney Guitars

Greg try a search in the archives we have discussed this a number of times, some of us are very keen on 'parabolic' bracing.

Try this link:

Parabolic bracing

There ar other discussions also.

ColinColin S38727.2357291667

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

Like me
I am definitely keen on parabolic bracing. I think it keeps the trebles sharp and allows the bass to boom out loud. All depending on how you shape those parabolas of course.

Colin, your description is enlightening. I'd be curious to see what others who
have switched from "scallopped" to "parabolic" have noticed in terms of
sound, stiffness and so on.
Do you guys feel the bracing material makes a big difference, say between
sitka and red spruce? I don't think a lot of people would use cedar or
engelmann for braces on a steel string, but who knows?

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

It all depends on what you want. If you are looking for plenty of 'whomp' in the bass then scalloped bracing, low in the middle, will get it, possibly at the cost of some mid-range tone. For 'clear' trebles and sustain in the bass, 'tapered' bracing that's higher in the middle than at the ends will most likely fill the bill. There are variations on the contiuum between these two, and folks who are prepared to swear by, and at, each little difference. If everybody wanted the same guitar, there would be one, 'perfect', brace system. As it is, there are lots of things that work well for somebody, and that other poeple think are for the birds. It keeps life interesting trying to understand how all of this stuff works and when you might want to use one system rather than another.

Does anyone have photos of Parabolic bracing?

-j.

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“If God dwells inside us like some people say, I sure hope He likes enchiladas, because that's what He's getting”
-jack handy

[QUOTE=j.Brown] Does anyone have photos of Parabolic bracing?

-j.[/QUOTE]
Take a look here:

Scott Van Linge

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

I'm thinking about trying the parabolic bracing system on my new Martin Jumbo kit guitar. I'm checking Scott's page and the pic of the 'parabolic' bracing but the only place I'm seeing a parabola is in the cross section. Everything else just kinda sorta looks like some nice gentle curves on all the braces. Is that the idea or are there strict parabolas and shapes that I'm missing and which should be adhered to in this type of design?

Larry

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Thank You and Best To All

Larry,

I think this is why Howard K object to the use of the term "parabolic".

Parabolic strictly - it isn't. Nice gentle curves is what it is. Generally there is a high point and fallings away from this rather than "ups and downs" or "humps and bumps" that you get with scalloping. Mathematical functions with only one turning point - of which parabolas are one.

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

The cross section is closer to parabolic than the profile, but in truth neither are parabolic. My description would be eliptical or arched.

[QUOTE=Hesh1956]
1) Is the high point always in the middle between the ends except of course for the X-brace?
2) Are X-braces also shaped parabolically (is that a word...)?
3) Do you do this to the back braces also?
[/quote]

Based on what I've seen:
1) Not necessarily.
2) Yes.
3) Yes.

[quote]
Now for voicing since the braces are no longer segmented as in scalloped when removing material does this not change the symmetry, does it matter?

One observation that I have is that the parabolic shaped brace seems to lend itself to provide it's greatest rigidity in the middle and least at the ends. With the discussion on thinning tops out at the edges recently this seems like what one wants to do.
[/QUOTE]

They're not really segmented to begin with, even when scalloped. Asymmetry doesn't seem to matter overmuch; Dana Bourgeois, f'r instance, scallops one of the lower X-brace legs, but not the other.

All sorts of systems work, at the end of the day.

This is one of those quizzes where there really are no 'right' or 'wrong' answers. Some stuff works better than other stuff most of the time, and there are some things, like no bracing at all, that don't work very well or for very long, but other than that....

Every choice you make influences the sound and playability and longevity and stability of the instrument you make in some way, but if you stay pretty broadly within the range of the 'normal' you won't build an absolute disaster. A lot of the stuff that Dana does, or any other experienced builder does, is the result of a lot of experimenting and tweaking and too much coffee and pizza right before bed time. It works for them, and they can justify it bacause of something the apparition of their Grandmother said when she appeared in nine colors after the pizza episode, but there might not be a lot of logic involved.

So, yes, 'parabolic' bracing works in it's way, and has particular effects on the tone. These are hard to characterize, in the same way that all tonal effects are. You'll just have to find a guitar done that way and listen to it. Remember, too, that a system that works well on one particular design, or specific piece of wood, might not work on another design or on the same design with different wood. Just as there are no 'right' or 'wrong' answers there is also no single answer that is best in every case. That's what makes this so much fun?

Sometimes I'm so helpful it's scary..... :)

Allen your last line is trurer than you know........ We depend on you to keep us on the stright and not so narrrow path this craft has laid out for us.

Yes Alan...I, for one, am usually mesmerized by your answers and actively seek out your posts. (On the other hand, I don't always understand what I read, and my wife says I can be rather dense.)

Either way, carry on.

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Eagles may soar, but weasels don't get sucked into jet engines.

I too, am confused by what is meant by parabolic braces. In the following picture, all of the shape could be called parabolic provided that the curve is a section of a parabola. The top picture is a cross section.

[QUOTE=Mike Mahar] I too, am confused by what is meant by parabolic braces. In the following picture, all of the shape could be called parabolic provided that the curve is a section of a parabola. The top picture is a cross section.
[/QUOTE]

Mike - true you can probably make any curve shape out of sub-sections of parabolas!

My interpretation (and I stress this is just my take on the philosophy) is that it is the top of the brace shape that matters so in your example the top two pictures are "parabaloid" but not the third as the curve is inverted and the brace has a dip and curves back up again.

Interestingly, with arched/domed/ tops and backs the bottom of the brace is also "parabolicish" shaped too.

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

Mike I'm a keen user of 'parabolic' braces but always use the term with reservation. What I really mean is braces not scalloped but uniformly curved. The 'parabolic' braces I use would have the cross section you give and would then be at their highest towards the middle of the plate and curve down towards the edges of the plate much like the end section of your middle drawing. My X braces only have a very short scalloped section at the end, where they are tucked. The main principle for me is no 'pointy bits', just nice progressive curves.

Yes Hesh, I parabolic on the back braces as well, often using an X brace in the lower bout.

Colin

Colin

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

[QUOTE=Dave White]

My interpretation (and I stress this is just my take on the philosophy) is that it is the top of the brace shape that matters so in your example the top two pictures are "parabaloid" but not the third as the curve is inverted and the brace has a dip and curves back up again.
[/QUOTE]

David, please excuse my crude drawing. The third picture wasn't supposed to curve back up; it was supposed to represent a section of a parabola. Also, the second picture probably should have started curving down sooner. Once again, this is because I'm using a primitive paint program to the drawings.

You are right in that in the third drawing it isn't the brace that is parabolic but the cutout it. ie the brace lies outside the parabola. In the second, the brace lies inside the parabola.

I'm inclinded to think that, if you are going to use a precise mathematical term to describe something, you should try to it. I'd be more likely to just say curved braces as opposed to scalloped or straight.
Mike Mahar38730.4216550926

Here's a personal flash - I was re-shaping my Martin Jumbo Kit back braces last night to try and get these cool curves that were 'parabolic' or some other interpretation of the term and I finally got it - for me.

I simply started re-shaping and by the time I was done, I got down to 400 grit sandpaper and they were smooth as glass and they just LOOKED SO COOL!! At that point I was done worrying about the parabola police coming to check the mathematical functions and was just excited about the new shapes and can't wait to hear what the guitar will sound like.

Can't wait to play with the top braces.

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Thank You and Best To All

[QUOTE=Mike Mahar] I'm inclinded to think that, if you are going to use a precise mathematical term to describe something, you should try to it. I'd be more likely to just say curved braces as opposed to scalloped or straight.
[/QUOTE]

Mike,

Language is a wonderful thing isn't it. Lots of evolution and interesting adaptation to "fit" different things - a bit like making a guitar. Whereas mathematics has a reassuring precision - although it's roots are based in philosophy and very abstract (proving things is a bit problematic, you always seem to arrive at some fundemental assumptions).

One of my favourite examples is the word "manufacture" which, I think, comes from the Latin manus factore - to make by hand. So strictly a "manufactured guitar" would be one that is made by hand, but this is not how many people would interpret the phrase today.

Don't get too hung up on the words - I bet one would be hard pressed to find a guitar that confirms "perfectly" to a mathematical spherical top or back shape even though they are often described as such and are assembled in spherical forms. Wood is wood and bracing isn't uniform across the whole of a guitar's surfaces.

Like Colin I try to avoid any abrupt cnanges in brace shape, and I don't scallop the ends of my X braces - they come down gently following the overall curve to fit into the X brace pocket, so for me it's nearer to the second of your drawings rather than the third. In terms of the cross-sectional shape, sometimes I do them like your first picture, but at other times I use a more triangular shape.

What's the mathematical formula for a scallop by the way? They sure do taste good pan-fried

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

Dave I love your Bishop Hat Bracing

Language both evolves and devolves. When a term with precise
meaning is rendered less meaningful by its use in place of a term with
less precise meaning, we have devolution.

Using "parabolic" in place of "convex" or "arched" is a case of devolution.
Combine it with guitarmakers' recent predeliction for calling the creation
of any convex curve "radiusing," and soon we will see someone talking
about radiusing their parabolic bracing. Analogously, I have already seen
a guitarmaker say he uses solid kerfing. Another says he is "kerfing the
sides" when he glues in the liners (at first I thought maybe he was
bending dry and cold the way drywall people sometimes bend wallboard
to a curve by scoring it). Yet another talks about gluing in the kerfs.

This abuse of language tends to confuse other builders, but it has the
advantage of utterly mystifying the consumer. If it results in higher
prices, it will of course be a good thing.Howard Klepper38730.5953819444

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Yay Howard!

I'm sure a lot of the terminology used is more for sales purposes and developing a position in the market than anything else.

One user of parabolic braces maintains that the shape is nearly as stiff as a brace of uniform height with much less weight. This is probably true as stated, and certainly stiffness/weight ratio on the top is important. However, the bracing itself weighs far less than the top plate; often the bracing is no more than about 1/5 of the weight of the whole assembly, and no more massive than the bridge by itself. Small savings in brace weight per se don't buy you much that way.

We use bracing because it adds a lot of stiffness for a small mass, thus allowing for reductions in the thickness of the top plate, and a lower overall weight. Some of the newer systems, like the Smallman lattice and the 'sandwich' or 'double' tops amount to continuous bracing integral with the top plate iteslf, or nearly so. These things can be complex to build and tricky to 'tune' once they're together. The 'standard' systems represent a compromise between build time, tonal flexibility, and light weight.

At any rate, the way you shape your braces will have more effect on the stiffness distribution of the top than anything else, and that, in turn, will determine the relationships between the resonant modes. In most cases the difference in the lower order modes, that produce most of the power, will be small, but the changes in the upper modes, that determine the timbre of the guitar can be considerable.

Scalloped bracing, low at the center with high spots nearer the edge, will tend to drop the pitch of the 'main top' resonance and raise that of the 'cross dipole' relative to what those would be on a guitar with 'straight' bracing. This tends to make the lowest two peaks in the spectrum, from the 'bass reflex' couple, tall and broad, and lend a 'full' and 'bassy' sound. Because the top is less stiff in the center it can move a lot at the bridge location, and that cuts down on sustain. The low-end tone will be 'punchy', or 'woofy' if you're not careful.

'Tapered' bracing; tall in the middle and lower as you near the edges, works the other way. The top is relatively stiff in the center, so it's harder for the string to drive it, particularly at low frequencies. The sustain and treble tend to be greater, and there's a tendancy to 'clarity'.

None of this is etched in stone for the ages.

There seems to be a misnomer about what parabolic bracing is. Some folks errantly (IMO) think it has to do with the shape of the brace end to end in profile, but that is incorrect. It has to do with the cross-section of the brace.
Scalloping is merely removing an arched notch(es) out of the profile.

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"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."