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I had an exchange with a high profile builder today on another forum. He asserted that the normal thin "grafts" used inside the soundhole by another builder in the thread were insufficient to withstand the force of the tongue and that replacing them with braces would reduce or eliminate the need for ever resetting the neck. I responded that I use a soundhole reinforcement that covers the entire area under the rosette. He responded that "he hoped" I wasn't using that alone unless it was "massive."

I replied that when I attended Bryan Galloup's school we were all taught to use the thin braces under the soundhole, and that Bryan's high end guitars use the same exact soundhole reinforcement that I use. I also noted that guitars I made years ago haven't moved more than 1/64". I received a rather stuffy "fine then, good luck to you."

How do you approach the soundhole reinforcement issue? I am hesitant to give serious consideration to changing something that seems to be working just fine... not to mention that several pro builders I know and respect are using the same bracing pattern.

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It will probably be alright.

I make 5/8 wide by about 3/16 tall.

Like you I use a reinforcement patch under the rosette area. It butts up against the "X" brace and the upper transverse brace. I've always used this and like you have seen little to no movement on the tops of my older guitar (some 10+ years). A few years ago I also started using an "L" shaped neck block with an extension that goes under the fingerboard and also butts up against the UTB. And this may be over kill, but I now have added 2 small ¼" braces (about ½" high) that are on the left and right sides of the sound hole. These ¼" braces are fitted into the X and UTB. The result is an extremely stiff upper bout.

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Josh House

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Before I had to quit, I was using a full doubler with the usual braces too with no ill effects.



Nothing is more important in ladder bracing than to not have the sound hole "potato chip" so the doubler works there too, especially on 12 strings.



I remember many years ago a classical builder telling me that absolutely eliminating any vibrations from the sound hole was essential too.
Of course I always used a CF "A frame" tube affair from front block to buttresses at the rear of the instrument to keep the neck block from rotating.

If your necks are easy to reset, then it's really not that big an issue. But for integral neck builders like me, then it is. And I do use braces, about 3/8" tall, and notched into the upper transverse brace and X at 1/8" or so tall. My guess is that the added stiffness has a small tonal penalty, but does help structurally.

The upper bout structure has to be viewed as a whole, and yours, being based on a builder with many years of experience, should be pretty well proven good. Though that doesn't guarantee that it can't be better. Here are some of my theories from experience and pondering...

The upper legs of the X should reach significantly above the widest point of the soundhole. That's what really carries the stress in the standard X brace design. My third guitar caved in due to an excessively splayed X, resulting in the upper legs ending equal or slightly below the soundhole center. It had 1/4"x1/4" soundhole braces, which didn't help much.

There are two distinct forces being dealt with. First is the torque of the neck, and second is the compressive force in-line with the neck. A popsicle brace is actually tall and thin if you're looking down the length of the neck, so it's half way decent for that, but no good for dealing with the torque. And if you use a tall and thin upper transverse brace, then it's actually short and wide from the longitudinal perspective. Good for torque, but not compression. Though the plate itself is good for compression, so a tall/thin UTB preventing it from buckling may be all that's really needed.

The A-frame design, where you have braces notched into the headblock, passing under the UTB, and ending at the X, deals with both forces. Functioning as pillars to carry the compressive force past the soundhole, and as beams to resist the torque bending.

I like to use a big beefy headblock extension to prevent any bending whatsoever above the upper transverse brace. But if you do that, then you need a big beefy upper transverse brace as well, because none of the stress is being dispersed before reaching it. Mine is 3/4" tall and 1/2" wide, sort of wedge shaped cross section. Tall from both the torque and compression perspectives. But that still doesn't disperse the force, so then the area below the upper transverse brace needs to be stiffer, hence the soundhole braces. The end result is that the upper area retains its shape, and the whole box below the upper transverse brace pulls up over time. But that takes a lot more movement to raise the action compared to a small angular change of the headblock.

Everything changes if you use other structures like Haans' CF tubes to take a lot of the force.

Greg:
A guitar built with a good UTB and attachment points is not the weak point causing neck resets. The main reason for resets in my mind is a straightening of the longitudinal arch on the back. It requires very little movement there to cause a problem. As to the original question I use two angled braces 1/4" by 3/8" vertical. When I started buildingI used David Russell Young's book and he used this type of brace. Don't see any need to change. These along with the close lying X brace and UTB completely surround the soundhole. To me it's as strong as if there was not a hole in the top. Just my opinion of course.
Tom

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A person who has never made a mistake has never made anything!!!

It depends on your approach, obviously and what you are trying to accomplish.

For me flat, thin strips like you Greg and Bryan use and very minimalistic but only intended to reinforce the end grain that's of course exposed by cutting the sound hole. By the way that's exactly the functional purpose of a rosette too and all this time we thought it was just another pretty face and design... Because of the sound hole tops would split if there was not something glued cross grain such as the rosette and stiffeners/braces in the box. Some folks like braces, doublers, braces and doublers as Hans points out for ladder braced.

Lot's of bracing patterns make these "stiffeners" and make them braces or even buttress them against and inlet to the neck block. Should be pretty strong you would think, time will tell. So far many of the neck reset belaying ideas have not been around long enough to know if they work. I would consider the "absolute" nature of the original contention to have the jury still out.

I should mention that I never tried to rely on any sound hole structure to support my fret board extension and stiffen the top in that area. Instead my UTB (upper transverse brace) is laminated with .040 carbon fiber and won't flex at all as a result.

Different strokes....

Hesh, I bought a H165 off eBay. That's the mahogany topped harmony. Meant to copy the Martin015. It has gone through tough times. A flood that almost completely destroyed the top. The sound hole was sunken even after I re-glued all the braces. This guitar didn't have those braces. I was able to put some in and it raised the sound hole as well. I like those braces


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Hi Greg,
You are welcome to email me photos of your bracing and I can tell you if there is anything that might be problematic -- if you do, please include scale length. (info@fayguitars.com)

Here's something that I don't believe to my steel trap memory.... has ever been mentioned prior.

Regardless of how you brace inside the box around the sound hope if you sell your stuff and if gigging musicians are prospects for you be sure to understand the popular pick-ups out here, what people like and purchase.

Why? Because many of the pups will have some kind of control that mounts just inside the sound hole. LR Baggs and the Element, Anthem, and Lyric are prime examples. Your sound hole supports should factor in the control modules and where they are optimally located or your clients may end up with a pup choice and guitar that are incompatible.

Just a thought.

Was just looking at Han's work and let me tell you this is some of the neatest and likely best thought out work that I have seen!

There's an old expression - everything for a reason and that's where my mind goes looking at Han's work - beautiful, functional, superb craftsmanship and impressive as can be too! Makes me wanna build again....

Tom,-"The main reason for resets in my mind is a straightening of the longitudinal arch on the back. It requires very little movement there to cause a problem."
I really appreciate this notion. I had not thought about this. I used an elongated neckblock extending almost to the UTB and anchored the cutaway side to the block for 1.5 inches or so. Perhhaps a couple longitidunal back braces thru the center of the back would be helpful. I only used transverse back braces, thinking the sides would anchor the dome, but I suppose the dome must flatten for the block to rotate. Thanks

Thanks for all the feedback. Some good points made for sure.

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It will probably be alright.

I think the other builder has a point in that stabilizing the soundhole area will help to stabilize the guitar and reduce the need for neck resets. However, it is quite possible that your rosette doubling lamination is actually more effective at this than tall braces. It could be calculated. Perhaps one of the forum's engineer types has done some FEA modeling regarding this question.

Haans - I notice that the grain in the doublers is 90 degrees to the direction of the top grain. Would it provide more resistance to potato chipping if the grain was in the same direction as the top grain? Assuming the long grain stiffness is higher than the cross grain stiffness in the doubler.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

Hesh, thank you! You are a fine, long winded gentleman!
I hope you and your former? stones are doing better.
Jay, thanks for the question. It may be that aligning the grain the other way would help, or I have heard the 45 degrees to the original layer works too. However, I think (and believe me, I apply nothing but logic here) it is the glue joint that adds the stiffness between the layers here. I decided to try it on 12 strings and although my 12'a are very thick compared to the usual fare, they also use cables instead of strings. The doublers are pretty thin (about .040-50", and I rely on the glue to do it's part. At any rate, I figured if it works on 12's there is no reason it shouldn't work on sixes either. I have also used flamed maple on the UTB with no differences noted in a practical way.