I first became interested of the inner structure of the acoustic guitar many years ago, when I found a beat up, no-name guitar, destined for the landfill. I was just beginning to learn how to play the guitar, and was curious about how they were made. So I decided to take this junker home and perform a necropsy on it. What I found, once I  removed the top, was both fascinating and perplexing. The kerfed linings and bracing were very crude and rough. There were gobs of glue everywhere, and the braces and other parts were as rough as kindling. The construction was very crude and slapdash looking.

   Later on, I learned that the bracing of this guitar’s top was a Martin-style X-brace pattern, with the primary X brace, the two finger braces on each side of the X, and the two transverse braces in the lower bout, below the bridge plate.

   Even then I recall being puzzled as to the logic of the placement of those two diagonal braces. The top of this old beater guitar was badly distorted, no doubt from years of string pull and general abuse; and it seemed odd to me that there wasn’t some interior structure back there behind the bridge to counteract all that stress and torsion. I also couldn’t see how those two braces would effect the tone of the guitar in a positive way.

   Thus began my long fascination with guitar design.

   On the flip side, however, countless numbers of mediocre and poor guitars have also been built, using the same general idea. So, what are the factors that cause one guitar to have outstanding tone and response, while another, similarly built instrument, sounds dull and uninspiring?

At the risk of sounding simplistic, I think it all boils down to the skill, judgement, and craft wisdom of the person who builds the guitar. There is no one, be-all, end-all recipe for assured success.

  I also believe that there must be other, better ways to brace a guitar top for maximum responsiveness, while also improving the long-term structural integrity. I’ve always been a bit of an iconoclast, and I rebel against ideas like, “Why fix what ain’t broke?”, or “This is just how it’s always been done, end of discussion!”. So, when I first began thinking about how I would do it, I had to think outside the box, so to speak.

  

  I had a major EUREKA moment some years ago, while reading a book by S. Azby Brown, titled, The Genius of Japanese Carpentry. The book is an in depth study of traditional Japanese temple construction. It was fascinating to learn that ancient timber-framed Japanese temples, built many centuries ago, still stood intact and strong, because the designers and builders had such a deep understanding of structural engineering that they could make a building stronger than the sum of its parts. That is, considering the vectors of force acting upon a building, the architecture of timber-framed structures could be devised in such a way that, as the weight of the building settled into itself over decades and centuries, the structural timbers would actually lock in more and more tightly, and become stronger and more stable, over vast expanses of time.

   I know, I know, acoustic guitars and ancient Japanese temples are not very similar in most respects. But the idea began to coalesce that the guitar soundboard should be designed as a fully integrated unit, as with the timber frame of a Japanese temple, rather than a collection of loosely connected parts. Further, the bracing structure should distribute all the force vectors working on the top more equally than the standard Martin pattern. This, in theory, would allow a lighter overall construction, but with fewer high-stress areas that would be prone to distortion over time.

   I began sketching out numerous patterns that I thought might accomplish these fundamental criteria. In the first place, the primary X brace made perfect sense to me. The X brace was essential, so I kept that in the design. 

    It seemed a natural extension of this idea that all the braces should be mechanically connected, using joinery rather than just butting the sticks together with dabs of glue. This way, there would be less entropic dissipation of vibrational energy. Everything should vibrate and move as an integrated unit.

Therefore, I decided that all the secondary braces should be pocket-joined to the primary X brace, as seen in the photo here.

   Then, there was the consideration of the pattern, or array, of the secondary braces. I took my main cue for this from observation of the fan bracing that has been used as the traditional way to brace the Spanish classical guitar. Structurally and acoustically, using three fan braces arrayed equidistantly between the lower legs of the X brace really appealed to my sense of architectural proportion. This made a lot more sense to me than those two Martin-style, transverse braces.

   These three fan braces could be made light and slim, continuously tapering thinner out toward the edges, and would provide structural strength behind the bridge, with very little mass, as well as a pathway for even, balanced vibrational excursion throughout the lower bout of the sound board. Further, by selectively carving the braces in tapered, parabolic arches, each one could be attenuated to shape the sound and response of the top.

  The key to this entire concept is that the top should be built to function like the cone of a speaker, so that the sound box would move air efficiently, creating a balanced, focused sound.

   You see the logic I was chasing here?

(Pause...)

   Most of this cogitation on guitar design began long before I ever had a chance to do some hands-on experimentation. In year 2000, when good fortune and circumstance finally brought the opportunity home to me to try my hand at guitar making, I had a chance to build my first guitar, and see if my theories had any real merit. I feel fortunate that I was able to follow my whimsey and do whatever I liked, rather than being in a formal educational situation where I would have to follow the standard, rote process. I decided to make the first guitar with my X/fan hybrid top bracing ideas, and hope for a good result.

   Finally, the moment of truth, when it was all done and ready to string up for the first time. The first note from the first string was thrilling beyond words!

   After the guitar had a little time to settle in, and I got the setup worked out, I did some in-depth exploration. Right out of the starting gate, that guitar sounded huge, and colorful, and three-dimensional, with mind-boggling sustain. I was overjoyed by the result; after all this work and all this time, I had actually built a guitar that sounded like a million bucks! Maybe it happened accidentally; but it was accident-by-design!

   Oh, I was so full of myself! I imagined meeting the ghost of C.F. Martin the first, looking him square in the eye, and smugly saying, “So, C.F., what’s up with those two tone bars in the lower bout...?”

   Since that first guitar, fourteen years ago, I have used the same bracing pattern in all my steel-string guitars, with only minor modifications to the design. Time after time, the Edwinson X/fan hybrid top bracing proves out as a success.

  My guitars do not sound like Martins, but I never intended them to. I figure that Martin, and many other great builders who make guitars in the Martin style, have already staked out that territory, and they have my profound, eternal admiration and respect. But I do not wish to encroach upon their domain.

Many of these players used Ervin Somogyi’s brilliant guitars in their pristine, unembellished, state-of-the-art analog recordings, and THAT was the sound that became my holy grail. I later came to find out that Somogyi has continually experimented with, and refined his soundboard bracing methods for his entire 40-plus years in lutherie.

   The guitars I have most admired for the longest time have been the ones built by Stefan Sobell, Ervin Somogyi, George Lowden, and others in that league. More recently, I have found a deep admiration for modern builders like Tim McKnight, Jason Kostal, and Ray Kraut. (Jason and Ray, by the way, refined their lutherie skills through apprenticeships with the Grand Master, Ervin Somogyi.)

   Jump on over to my Favorites page for links to some of my other most admired luminaries of the Craft.

  I do not have an interest in keeping my bracing and engineering ideas proprietary. If any other builders find an affinity with the ideas presented here, feel free to use them, in whole or part. As I previously mentioned, the success or failure of any theory of construction will depend on the skill and judgement of each individual builder. If you think the “Edwinson style” has merit, and you’d like to try some version of it, I’d be honored. All I ask is that you provide appropriate attribution to the Edwinson, if anybody asks.

   So, in the interest of full disclosure, here are some of the finer details of the Edwinson plan:

   The primary X brace, and the upper cross brace (right above the sound hole) are the primary braces.

   There are three fan braces, equidistantly placed in the lower bout, and pocket-joined to the X brace. These are the secondary braces.  My aim is to make all of the braces function as an integrated unit.

   On either side of the X bace, I place another brace, which I call the “Lucky 7” brace. On a guitar designed for heavy-duty rhythm or flatpicking, I may put two Lucky 7’s there for extra support.

   I do not generally scallop-carve any braces. I believe the vibrational excursion will be most efficiently served by using a gradual taper, thinner out toward the edges of the soundboard, and shaping the braces parabolically.

 

   I have found that this bracing pattern is very controllable and predictable, and can be modified and optimized in various ways, to achieve the desired tone and structural integrity for different playing styles.

  At left is a top for a guitar I made for my friend Brent,  who is a high-octane country rock frontman and rhythm player. Brent needed his guitar to hold up to the rigors of aggressive playing and a life onstage. I’ve added some extra sound hole reinforcement, and two Lucky 7 braces per side. The fan braces are brought closer together to give the top more of a focused long dipole motion for heavy-duty rhythm playing.

   I had to think long and hard about how to brace this top, and this is what I came up with. The guitar turned out to be a resounding success,  sounds like a seven-string grand piano, one of the best sounding instruments I’ve made to date.

   And here (left) is a new pattern, the Ellipse/fan, the pattern for the new Consort Crossover Nylon string guitar, built in 2013. 

Same principles apply to all these patterns. Everything is evenly spaced, and the whole pattern is linked up. All the braces are tapered and parabolically shaped. 

 

 

One thing is true: There are a lot of effective ways to brace a guitar top. Some work better than others. I’ve found one that completes the equation for me.

When it comes to philosophies of guitar design, I see no reason to differentiate between evolution and intelligent design. These are NOT divergent concepts. Intelligent design is what makes evolution happen.

   umm...We ARE talking about guitars here...   Politics and religion can be found elsewhere.

   Now, in closing (because I’ve droned on long past closing time-- again!), I want to point out that the top bracing ideas elucidated here are only a part of a larger system of design. I have tried to make all the engineering in my guitars into a synergistic system.

Thanks for looking!