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The Inevitability of Scalloped Bracing: Resistance is Futile


strayGoat
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Howdy fellers!

 

This has vexed me a bit for years- trying to understand why several prominent acoustic makers are still resistant to scalloping their braces. Particularly, lookin' at you, Yamaha and Larrivee. Several years ago, I owned a Larri D-60. Nearly perfect for me - at the time - in every single respect. Except for the frickin' non-scalloped bracing, which naggingly muted the guitar and ultimately led to me selling it off. So why didn't I just get an HD-28? Probably because I'm an idiot.

 

Still, what accounts for the reluctance of JL to scallop? To forward-shift? Is it merely a desire to be different from Martin and other existing brands? Or is it more- as I tend to suspect - about overbuilding out of fear that a bunch of customers will start demanding warranty-covered neck resets?

 

Yamaha has actually begun scalloping the braces on their FG line, which I think is absolutely brilliant. I have a Yammo FG730S (the non-scalloped predecessor to the FG830), and I love it. Will never let it go. Not that it's the best guitar ever made, but it was made with excellent attention to detail, plays very comfortably, stays in tune, sounds like a guitar and has never let me down even when busking in the busking-hostile streets of Philly. But I have fantasized once or twice about replacing it with the new scalloped version...

 

Annoyingly, Yamaha has not carried this practice over to their LL series. I also own a LL-16. Like my bygone D-60, the LL checks all the boxes for me... except for the damn bracing. Somewhat less annoying in the case of the LL compared with the Larrivee, because the former is of course significantly less expensive. I like it too much to get rid of it, so I've decided I'm going to try to do a Bryan Kimsey bracing surgery in it. Wish me luck.

 

Larrivee, also, has introduced a "hybrid" scallop/parabolic bracing system in their 40 series. Again, though, rather frustrating that they are not bringing that concept to their higher-end guitars. Or ALL of them, for that matter.

 

Ultimately, I just do not see what is to be gained by not scalloping. Does anyone here see a particular advantage- tonally, that is? It just seems to me that Yammo & Larri's respective, tentative forays into scalloping, finally, reveal a grudging admission of the obvious voicing benefits. It seems inevitable to me that both brands will adopt the practice on a broader scale. I just wish they'd quit taking so frickin' long.

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Stray, old buddy, why do you assume that the only way to brace a guitar is to scallop them? Martin makes many guitars with non scalloped braces (including some dreadnoughts)

 

https://www.martinguitar.com/features-materials/bracing-patterns/

 

Here is a wonderful (if somewhat dated) gallery of bracing patterns

 

http://www.frets.com/FretsPages/Musician/Guitar/XGallery/xgallery1.html

 

Taylor just launched a whole new bracing concept (the jury is still out) to replace their scalloped braces

 

https://www.taylorguitars.com/guitars/acoustic/v-class-bracing/story

 

Last time I looked Larrivee was tapering his braces and, interesting to me, using symetrical tone bars. Paul Reed Smith did just the opposite and put fan braces inside his X instead of tone bars. And of course there is the whole world of lattice bracing and other "modern" patterns.

 

Some of the best guitars that I have made have not been scalloped, some of them have. I won't bore you.

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I also presume that you understand why a brace might be scalloped or tapered. That the stiffness of a beam (which is what a brace actually is) is directly proportional to its width, but proportional to the cube of its height. If you make a brace twice as wide it will be twice as stiff, if you make it twice as tall it becomes eight times as stiff (or conversely, if you make it half as tall it becomes one eight as stiff).

 

And a "brace" serves as least two competing functions - first it must give strength and stiffness to the top, particularly rotational stiffness around the axis of the bridge and cross grain strength. It must transmit the movement of the bridge to the top - one of the reasons the bridge wings sit directly over the X, It must allow the top to vibrate in a fairly complex fashion - this is what all the work with "modes" and "glitter patterns" is all about.

 

A good luthier uses the material properties of the wood that she has selected to make all of that happen. I have sat in seminars by John Greven, Dana Bourgeois and Roger Siminoff, as well as a couple of classical guitar builders (where braces are almost never scalloped) and each has explained his approach to voicing the guitar. I can promise you that its a whole lot more complex than just scalloping the braces.

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Scalloping the braces can make a great sounding guitar when everything else lines up....but it makes shaping the sound of the guitar more unpredictable and can sometimes lead to tops that are so soft and pliable that they don't last and a neck reset is required after a few years. The practice seems to bring out bass in smaller guitars but probably isn't as beneficial to drednaughts and jumbo guitars....which is why Martin originally abandoned it in the 1940's. The guitars had got so big that scalloping wasn't as necessary and demanded more warranty work. Personally I prefer tall thinner braces on my guitar builds because they have the highest strength to weight ratio. The trick is to taper them as much as possible in the periphery of the soundboard.

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Good questions demand good answers, or so I've heard. Therefore, I have none to give. Thinking about it, though, if the two (major) manufacturers have succeeded to produce popular demand (respectable market share) for their products, and have taken into consideration all the technical nuances of making guitars, one might think they've assessed the returns of scalloping braces by now.

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Remember that there is a whole lot of difference between making a big pile of (scalloped) braces and gluing them to a top in a big production line and hand removing material one at a time until some sort of affect is achieved

 

And, therein lies the quandary.

 

 

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Huh?

 

 

Hey FK!

 

Is what I'm trying to get at here really so mysterious? What I meant was that I get the sense that certain builders - Larri in particular - have long resisted scalloping less out of a conviction that their own bracing system yields a more desirable tone and more out of concern that reducing the mass of their bracing will make their tops explode.

 

I cannot recall who said it (CFM? Richard Hoover?), nor the precise phrasing, but it was along the lines of, "If you want a good-sounding guitar, you have to tweak the bracing to the point where the top is in danger of exploding." Again, that is a ROUGH paraphrase. But I tend to agree with the basic sentiment.

 

To your point about there being many non-scalloped bracing systems out there, yes. I don't mean to suggest that I think there's only one way to make a "good" guitar. I've owned a couple of non-scalloped Martin models (an old D-1, a D-15M). Past tense. Reason being, I just don't think they hold up very well against comparable lighter-braced dreads. Didn't Bryan Kimsey work on a D-18 of yours? But also to your point, perhaps I should really be referring to bracing with reduced mass rather than specifically "scalloped" bracing. Because ultimately what I mean is that I think virtually every acoustic guitar made by Larrivee and Yamaha would benefit from lighter bracing. Evidently, Larri and Yamaha agree (at least up to a point), or they wouldn't be adding the practice to some of their models. OTOH, maybe they are simply reacting to market demand rather than a sense that their systems *need* upgrading- I have no idea.

 

I will say that I think the post-2012 D-18, with its scalloped & forward-shifted bracing, is an infinitely more appealing animal [to me] than its non-scalloped predecessor. Kind of a side note: I find myself more or less constantly wanting a D-18 because I love the current iteration so much. But my love affair with my M-36 has me wanting to experiment, so I'm planning to try building something along the lines of a D-18 with an approx. 4" depth.

 

I used to spend a lot of time staring at Frank Ford's pics of various braces. Thanks for posting that! It's interesting as hell. And where my own builds are concerned, tbh where I generally lean is toward narrower, taller braces as opposed to actually much in the way of "scalloping." So again, a bit of a misnomer on my part in the OP.

 

I ran across a pic of Taylor's new "V Class" bracing only very recently, and it looks REALLY interesting in that it seems to leave a pretty large bit of top surface unencumbered. I would really love to try out one of their guitars with this bracing.

 

I'm currently repairing an old ladder-braced dread for a friend. Hondo. All lam. I think he bought it at Sam Goody many years ago for 150 or so. Funny thing is, it's really not a bad-sounding instrument.

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My "huh" was that the need for a neck reset has very little to do with the type of bracing a builder chooses. Both my "over build" non scalloped '74 D-18 and '80 D12-28 required resets. Its the nature of old guitars. My 1969 Yamaha (very lightly braced but not scalloped) also required a reset.

 

And yes, you are correct, I did have some work done to the D18 to lighten it - smaller bridgeplate and some shaving of the braces. Mostly to reduce their height, not necessarily give them the suspension bridge shape that we call scalloped. They were just too damn big, thats how Martin was building at that time.

 

It has been one of the really interesting parts of learning to build guitars to try to understand how all of this work. I have sat at the feet of some real masters and maybe learned a few percent of what they do automatically. I'm happy with each of my guitars, but I've got a long ways to go. In fact when I finished my last one (cedar over coco OM) I was a bit disappointed with it - grabbed my little palm plane and a hunk of 100 grip sand paper and reached inside the soundhole - did my best Kimsey number on it and its definitely better. I guess I'm learning where that "danger of exploding" line is and I need to keep pushing it.

 

The other thing I keep learning, or maybe not because I keep repeating the same mistakes, is how hard it is to improve on guitars built in the 1920's and 30's - when I follow the patterns that were laid down way back then I seem to make my best guitars.

 

 

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My "huh" was that the need for a neck reset has very little to do with the type of bracing a builder chooses. Both my "over build" non scalloped '74 D-18 and '80 D12-28 required resets. Its the nature of old guitars. My 1969 Yamaha (very lightly braced but not scalloped) also required a reset.

 

And yes, you are correct, I did have some work done to the D18 to lighten it - smaller bridgeplate and some shaving of the braces. Mostly to reduce their height, not necessarily give them the suspension bridge shape that we call scalloped. They were just too damn big, thats how Martin was building at that time.

 

It has been one of the really interesting parts of learning to build guitars to try to understand how all of this work. I have sat at the feet of some real masters and maybe learned a few percent of what they do automatically. I'm happy with each of my guitars, but I've got a long ways to go. In fact when I finished my last one (cedar over coco OM) I was a bit disappointed with it - grabbed my little palm plane and a hunk of 100 grip sand paper and reached inside the soundhole - did my best Kimsey number on it and its definitely better. I guess I'm learning where that "danger of exploding" line is and I need to keep pushing it.

 

The other thing I keep learning, or maybe not because I keep repeating the same mistakes, is how hard it is to improve on guitars built in the 1920's and 30's - when I follow the patterns that were laid down way back then I seem to make my best guitars.

 

 

Re. the bolded portion, I don't know that I'd agree. All other things being equal, surely significantly lighter bracing will contribute to accelerated bellying, etc., which will eventually necessitate a neck reset unless correctible via something like a JLD- a faster eventuality than with more overbuilt guitars. I consider Martins in general to be exceptionally well constructed, but have known a few to require resets within only a few years of purchase [new]. From memory, in Frank Ford's bracing photos there was one of a Breedlove's interior with some very aggressive scalloping, and the JLD-like device they used to use as a standard countermeasure (I'm not sure whether Breedlove still does this).

 

It's good to hear that you were able to improve your OM (cedar over cocobolo must be damn nice) by Kinsey-style tinkering. This is what I'm planning to do with my Yamaha LL-16. And I was planning pretty much the same tool approach - little green German palm plane from LMI (what an incredibly useful tool that little thing has been!). Hopefully I won't screw it up...

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Re. the bolded portion, I don't know that I'd agree. All other things being equal, surely significantly lighter bracing will contribute to accelerated bellying, etc., which will eventually necessitate a neck reset unless correctible via something like a JLD..

 

The paradox is that the same static torque that is rotating the top around the bridge axis is what allows the guitar to make sound. CFM's first use of the X brace was pure engineering genius - it puts the stiffest part of the brace (the crossing of the X) at the weakest part of the top (between the sound hole and bridge) and lets the builder futz around with top stiffness in the lower bout to get whatever sound he/she thinks is desirable. If you look at my picture below, that is very typical of a scalloped X braced guitar - notice that the brace above the X are pretty tall and not scalloped (the old cube formula). Also the big UTB and popsicle brace above the soundhole - trying to keep from driving the neck thru the top of the guitar.

 

[img2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i51.photobucket.com\/albums\/f387\/Freeman_Keller\/00-Mahogany\/IMG_1015_zpsc03c8142.jpg"}[/img2]

 

Here is kind of an interesting comparison, this is a small bodied guitar with non scalloped braces - they are thinned quite a bit but full height. Also notice no popsicle - smaller upper bout so I thought I would leave it out (some vintage Martins don't have it, even on big bodies)

 

[img2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i51.photobucket.com\/albums\/f387\/Freeman_Keller\/0-42\/IMG_2372_zpsiowxmevv.jpg"}[/img2]

 

A little anecdote about that last guitar - it was submitted to the Steel String Listening Session at the last GAL conference. During the Session 35 different acoustic guitars were played by the same player in the same venue - an incredible opportunity to hear all the subtle and not so subtle difference. After the session a guy came up to me and commented on the little parlor - he said it was amazing loud, where he was sitting it had some of the best projection of any of the guitars in the session. I asked where he was sitting, he said the very back row.

 

Edit to add, my one experience with the JLD was not good. The fact the Breedlove made them work was a result of engineering it into the overall brace design. I don't know if they still use them on their domestic guitars, I know the PacRim imports have standard bracing.

Edited by Freeman Keller
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It just depends on the sound you're after. As I understand it, scalloping boosts the lows. If you're already getting enough lows, the last thing you'll want to do is have someone scallop your braces.

 

Never had trouble getting good sounds out of guitars whose bracing wasn't scalloped - a D-28, a D-35, a few Gibsons, a couple of Guilds. And if you like plugging into a preamp or acoustic amp, more lows can boom you out of the room.

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The acoustic guitar is such a guesswork collage of joined pieces assembled without a science in its underpinnings that discussion about best practices brings the chuckles. Empirically we can say something works, create an assembly from that experience, and then sound like we're babbling bull rather than baffling with brilliance when asked why it works. But, at least it costs a lot, takes a lot of effort and a long time to make one. Those three things have always been the hallmark of an artisan so, even if the build sounds crappy, we still have that and the guitar itself can be said to have been designed for Da Blues. Gibson has been getting by with that forever.

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. . . Edit to add' date=' my one experience with the JLD was not good. The fact the Breedlove made them work was a result of engineering it into the overall brace design. I don't know if they still use them on their domestic guitars, I know the PacRim imports have standard bracing.[/quote']

As with a lot of things, it varies. According to Breedlove's web site, the entry level Discovery models don't have it, while the Pursuit, Solo, and Stage models do. All those are PacRim made. From what I can tell, some US made models have it and some don't.

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The science and the artisan are mutually opposed. The former denudes the latter and the latter is duly offended by it. In any case, the sciences have been visited by at least a few of the artisans whose curiosities got the better of them.

 

 

http://www.barbarossa-guitars.com/misc/AL-100_Artricle/Struct.htm

 

How Stiff/Strong Should I Make the Brace?

In his article entitled “On the Selection and Treatment of Bracewoods”, American Lutherie #60, Ervin Somogyi wrote, “… I’d been careful only to use vertical-grained material [for guitar braces]. That was, after all, what everyone had told me to do, since the very beginning. But I’d not done anything to determine whether any selections of vertically-grained woods really were the stiffest. I did know, from previous experience of overbuilding, that you could make things too stiff. And, likewise, too loose. So, where to draw the line?” Exactly; there’s the eternal question: How stiff? After hearing the information presented here, luthiers always ask, “so what brace size/shape/height/width/material should I use?” I always answer with a question, “What do you want the brace to do?” The braces at the neck end of the top are there for strength. Upper bout transverse bars, usually the heaviest braces in the guitar, keep the upper bout area from collapsing under the string forces. The braces around the sound hole reinforce this big weakness in the top, which is right in the line of the force of the strings. (You would have a hard time picking a worse place to put that hole, from a strength standpoint.) The other braces, in my opinion, are there to control the vibrations of the top and, to a much lesser extent, to react the twist of the bridge (for strength.) You could make a guitar with no top braces. It would have to have a very thick top to not collapse. It probably wouldn’t sound very good. Clearly, some sharing of the load by the braces is needed in order to free other parts of the top to move more. The top (and back) is a stiffened-shell type structure, like most structures that we use (airplane fuselage, airplane wing, house walls, floors and roofs, car bodies, boat hulls, etc.), for a very good reason. A stiffened shell is the most weight-efficient way to make these structures.

I have no formula for a good sounding top/guitar. I use my ears and tap parts all through the stages of construction so I can hear how they are reacting to vibration. I think my guitars succeed quite well: I am pleased with the volume, tone, and overall effect. But I have no formulas. I flex and tap, flex and tap – and listen.

 

 

[ATTACH=JSON]{"data-align":"none","data-size":"full","title":"Struct3.gif","data-attachmentid":32286530}[/ATTACH]

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