Soundbox Geometry and Architecture

Thu, 3 Dec 2009 01:19:54 -0800

Fundamentally, the acoustic guitar soundbox is an air pump, which is activated by the energy of vibrating strings, played under tension. To produce sound, the air volume inside the soundbox must be excited by a focused, percussive force , a pick, a strum, the energy of strings in play.
Further, the geometry and architecture of the soundbox should be designed in such a way as to to shepherd the air movement within this acoustic chamber into pleasing and articulate projections of musical sound. That’s the distillation of all the reasons for the guitar’s form and function. All of Music devolves to the movement of air. Music is the reason to move the air. This is what we hear. We are marked by this experience.
This is the place where the science and magic of the acoustic guitar live, in grudging acceptance of each other.

There are myriad variables that go into play with every iteration of soundbox design. Our job as luthiers is to combine science, intellect, educated judgement, and intuition into the search for the golden mean, as we strive to build the most efficient, fluent, and articulate air pumps that our skills and instincts will allow.

This concept is elucidated brilliantly by Dr. Ervin Somogyi in his new book, The Responsive Guitar, which is absolutely essential reading for anyone who is interested in the finer points of acoustic guitar design philosophy, and its practice and trade wisdom, in the hands of a master.
The photo at left is Ervin, explaining these mysterious arcana in his lecture at the 2009 Healdsburg Guitar Festival. See also, the Contacts and Links and the Favorites pages, for more on Ervin Somogyi.

When I first set out to become a guitar maker, I did not wish to make copies or personal interpretations of any of the classic twentieth century Martins, Gibsons, or other popular brands. Nor did I wish to reinvent the guitar from scratch. But I felt certain that many of the staid traditions of acoustic guitar architecture were ready to take an evolutionary leap, and I intended to try to facilitate that with my own original designs.

Close scrutiny of the Edwinson guitar will reveal a number of departures from traditional flattop architecture. First, there are no actually flat surfaces anywhere on the soundbox, except where the neck joins the body. The top and back are both domed; The back is built to a fifteen foot radius, and the top to a twenty five foot radius.
There’s nothing particularly innovative about that. The radiused back has been commonplace in most acoustics for generations, and a good number of modern builders are using the radiused top now, as well.
It’s a commonsense idea, simple and elegant.
A slightly domed, or radiused, top is stronger and more stable against distortion from string pull than a standard flattop. When you think of the vectors of force being imposed on the top plate from approximately 150 to 180 pounds of constant string pull, over the working life of the instrument, it’s amazing that flattop guitars last as long as they do. In a good old flattop that has provided years of faithful service, you often see a pronounced concavity in the area between the soundhole and bridge, and a bellying up behind the bridge, as bridge torsion from string pull has deformed the flat plane into a wavy warp. This condition will often necessitate some expensive and difficult restoration work, often involving a neck reset and bridge modification. Sometimes, braces inside will pop loose, and have to be cleaned up and carefully reset.
The intrinsic strength of a slightly domed top will largely negate this type of distortion, particularly if the bracing underneath is also designed to provide stability where it is most needed (more on that later).
I also believe that coupling a radiused top with a radiused back will promote a more “lively” excursion of sound waves between the plates, than if the top was a flat plane. I’m not an acoustic engineer, but my gut tells me that curved surfaces facing each other will reflect sound waves more omnidirectionally, preventing standing waves, which just bounce back and forth and don’t really go anywhere. Standing waves inside the soundbox are what causes a boomy, woofy, or generally unfocused tone. At least, that’s my experience.

A primary design point that distinguishes an Edwinson guitar from most other acoustics is that the lower bout is actually the shallowest part of the soundbox. The deepest part is in the waist area, and then it tapers shallower again into the upper bout. You can see this unusual body shape in the photo at left.

Nearly every other acoustic guitar I’ve ever seen has a deeper lower bout, tapering shallower toward the upper bout. The common thinking is, the deeper the lower bout, the more bass response and volume you’re going to get. That may be true, to a point--but will that big fat bass also be articulate and clear? Will the mids and trebles hold their own in the mix? Many times yes, oftentimes not.

Every guitar I’ve ever made has the configuration seen here, and not one of them has ever had a thin, wimpy bass response or lack of volume. Quite the contrary, in fact. Based on my experience, you do not need to have a deep lower bout to get a lot of low end or volume out of a guitar. The most important thing is to set those sound waves free. How?
Well, you have to think as if you are sound waves, vibrating this structure.
Again, I’m not an acoustic engineer, so I can’t prove anything to you with graphs and equations, or specialized testing equipment. The proof is in the guitars, and the people who play them.

The reason I thought that a shallower lower bout would contribute positively to the guitar’s sound dynamics is that it makes sense to me that this shape would naturally project more toward the center, or deepest part of the guitar. Then those sound waves won’t be trapped down there in the dark depths of the lower bout. It’s all about the lively, unfettered movement of sound waves toward the area where the sound hole resides. When this happens, much less of that string energy is lost or cancelled, and the entire soundbox becomes a more efficient speaker.
I’ve built thirty-plus guitars this way, and every one has added proof to this theory.

An added bonus to this soundbox shape is that with a shallower lower bout, the guitar is very comfortable to hold and play. My Edwinson guitars are between 3 1/2 to 3 7/8 inches deep in the lower bout. So you don’t have to drape your arm over a really deep lower bout. It’s much less fatiguing on the shoulder, elbow, and wrist.
Last year, I had a torn rotator cuff in my right shoulder. I could still play my Edwinson without too much discomfort. I also have an old Alvarez Yairi dreadnaught that used to be my favorite guitar, which is 4 7/8 inches deep in the lower bout. I couldn’t even get my arm around it. I’ll always love that old guitar, but it just feels so cumbersome to me now, even though my shoulder is better.

Soundboard Bracing

Wed, 2 Dec 2009 17:08:25 -0800

I first became interested in the interior architecture of the acoustic guitar when I was in high school in the late seventies. I had a crappy, no-name guitar that had ceased having any utility as a musical instrument. It was literally coming apart at the seams. So I decided to disassemble the thing and perform a necropsy on the parts.
Once I got the top off, I had my first good look at a guitar’s innards. It looked like rough sticks of kindling, smucked down into gobs of glue squeeze-out. In retrospect, I realized that what I was looking at was a cheap, crude version of the X-bracing system that Martin had established generations earlier as the way it’s done.
Even back then, I recall thinking that the diagonal (transverse) braces in the lower bout looked a little odd. Why were they placed in that configuration? What was that configuration supposed to accomplish? Why was that configuration universally accepted and copied?
I couldn’t see how the transverse braces provided any real structural support to the top, with all that torsion from string pull going on, and the transverse braces diagonally opposing that force, well behind the bridge plate. (???) Nor could I wrap my head around the logic of how those two braces were supposed to help modulate the vibrational characteristics of the top. If anything, it looked to me like the purpose of the transverse braces was to squelch, or step down, the vibrational energy in the area that I thought should be the most acoustically active part of the soundboard.

Maybe I was just being dumb. But I’ve never been satisfied with dogmatic responses like, “because it’s always been done that way”, or “why fix what ain’t broke?”
When I began seriously studying lutherie about twenty years ago (from the layman’s perspective), my opinions started to become more obstinate. I was at sword’s points with tradition, and Tradition didn’t give a bent penny about my opinions. It was all speculation at that point.

The X brace itself was essential. That much was assured. The X, pocketed into the rims/linings, made perfect sense. The superstructure of the top is well supported when the X brace bisects the top into quadrants. With the X, it just made sense that the top would have major support where it needed it most, and yet would still have the freedom of movement to act as a tympanum, like an eardrum or a drum head.
But then there’s all the rest of the untamed sound board to deal with. I thought of it this way: If I were a sound wave traveling through this wood top, how would I respond to the placement of braces in various patterns? The movement of soundwaves seemed to have something in common with ripples on a pond, and the way the ripples disperse themselves when they meet a protruding rock or tree branch.
If I were a guitar top, how would my structural elements most comfortably find stasis with the forces of string pull? After a long time of contemplation about these issues, I developed an equation, the essence of which is balance.
The idea occurred to me that instead of those two transverse braces, perhaps three fan braces should be arrayed equidistantly in the lower bout of the X. There would be a bass fan, a center fan, and a treble fan.The fans could be made to pass under the bridge, mechanically linking with the bridge plate and the X, and then tapering out toward the rims.
I sketched out a bunch of iterations on that idea until I had narrowed it down to a couple of patterns that really appealed to my sense of architectural proportion. It just seemed natural that, not only would three equidistant fans distribute the stresses acting on a strung top more evenly, but also that the vibrational excursion of the top would be allowed to move in a dynamic but controlled way. Further, these fans could be individually attenuated (with carve, shape, and taper) to their corresponding frequency zone of the sound board. You could tune the top without a whole lot of guesswork. This idea made me so itchy, I knew the only way to scratch the itch was to actually build a guitar and see if my armchair expertise was worth more than a belch and a fart.
It took a while to happen, but a semi-miraculous series of circumstances aligned themselves in my favor, and...

Flash forward to the year 2000. Here I was, standing in a fully outfitted shop, with my new friend Aaron Andrews, who just happened to be a professional luthier and guitar repairman. With Aaron’s generous guidance, and borrowing his tools, templates, machinery, and instrument wood, I started building my first guitar. I used my latest theoretical X-fan hybrid idea on the soundboard. The top was domed to a 25’ radius, and the back to 15’. Woods used were Honduran mahogany back and sides, and a top of some nicely quartersawn Western red cedar with dramatic mineral streaking, that Aaron had bought for two bucks a board foot at the Dunn Lumber Company.
I had such a blast building that first guitar. It was a dream come true, finally getting a chance to do this. Especially when, after four months of working on it evenings, weekends, and vacation days, the guitar was finally done and ready to string up. I felt like an expectant father awaiting the birth of his first kid. Would it have the right number of fingers and toes? Would it have all its parts in the right place? Would it turn out smart, or average, or would it be tragically retarded?
Well, I have to say, my best hopes were realized. When I slapped that baby on its bum, it sang. And while my first guitar wasn’t exactly beautiful to look at, it wasn’t ugly either.
Right out of the starting gate, the first Edwinson guitar had more pleasing tonal character, volume, and sustain than any other guitar I’d ever owned. Granted, I’d never owned a really fine guitar, but this was like the difference between a skateboard and and a motocross bike. Everyone who played it agreed, it was an ass-kicking good guitar. I felt validated, redeemed, reborn...oh, I was so full of myself...I felt I could finally look the ghost of C. F. Martin the First straight in the eye, and engage him in a debate...”So, C.F., what’s up with those two tone bars in the lower bout...?”

Since the beginning, I’ve used the hybrid X-fan bracing pattern in all my guitars. I’ve never had a bad result. The design has undergone some gradual refinements, but is essentially the same as the first one. The first dozen or so Edwinsons had a rosewood bridge plate with an .030 brass plate epoxied in where the ball ends of the strings are anchored. I’m now making a bridge plate of laminated rosewood and aerospace-grade carbon fiber, which is very low mass, but very strong. (See the “Bridge and Bridge Plate” page.)
Originally, I used the two Martin-style finger braces on the outside of the X brace. I have since replaced those with a single tapered brace on each side, which I call the “lucky 7” brace. All of the secondary braces are pocket joined into the X, not just butted up with a dab of glue. The entire top bracing structure then becomes an integrated unit instead of a collection of loosely connected parts. I believe that this integrated structure gives the guitar’s top a very even, balanced vibrational excursion. It also provides a very solid and stable structural support for the top plate. The guitar would have to take a catastrophic hit to knock these braces loose.
There are three fan braces: The bass fan, the treble fan, and the center brace. Each of these braces is carved into a parabolic arch, and tapered down to the ends. The center brace is pocketed into the crotch of the X, and also pocket joined into the tail block. As you can see in the photo at the top of the page, the center brace “flies” over the bridge plate, to allow the installation of bridge plate transducer type pickups, such as the brilliant three-element K&K Pure Western Mini system, which I strongly endorse.
In addition to the X-fan braces, I place the standard cross brace in the upper bout, which works in conjunction with the spanish foot neck block to provide a stable platform for the fingerboard extension. I don’t believe that this upper bout area of the soundbox is acoustically active--it’s mostly reflective--so I beef up this area to provide plenty of distortion-proof support for the neck and fingerboard.
As you see above, the sound hole is reinforced with a cross-grained spruce or cedar “donut brace”. If I’m building a guitar for a really aggressive player, I’ll also add some additional bracing support around the sound hole. (see below.)

I’ve had very good success voicing the soundboard with this bracing system. The voicing process happens in several stages, including careful brace shaping and tuning, and graduating the thickness of the soundboard. Each guitar top I make is individually tuned to bring out the optimum desired tonal and dynamic characteristics. A guitar built for a Bluegrass flatpicker will get a different treatment than one for a Delta Blues fingerpicker. All Edwinson guitars have a very recognizable Edwinson sound, but there are degrees of refinement that can be built in to emphasize certain characteristics in the tonal palette.
In the last couple of years, I have heard of some other builders who are embracing the hybrid X-fan concept in their top bracing. Two that stand out are PRS Acoustic, and the great luthier Rick Turner’s Compass Rose acoustic guitar. I think the more people who try some version of this system, the more traction it will gain. I have no interest in keeping this bracing system proprietary. (If I did, I wouldn’t have written all that wordy explication, above.) So here it is, for all to see. If other builders see the logic at work here, and would like to try their own version of the X-fan, I say go for it. I think that might help to evolve the acoustic guitar for modern player, into new levels of refinement, to everyones’ benefit. Personally, I’d like to get a discussion started about how X-fan bracing works for other builders. And really, it’s up to the individual builder whether ideas like this will bear fruit. In that way, it’s no different than the traditional Martin pattern. The skill, care, and judgement of the builder are most important factors in a guitar’s success or failure as a musical tool. One thing about guitar making that I most appreciate is that the craftsmanship and judgement of each builder can’t be faked. Guitars, whether they’re good or bad, are incapable of lying about themselves. You can’t pass off a poorly designed and built guitar as a good instrument. Likewise, a brilliant guitar can only give its honest testimony in the player’s hands.
And let’s not forget how broadly subjective all this can be. One person’s crappy old beater guitar may be another person’s funky, awesome stringola juke box. After a guitar is built, it’s the player who ultimately completes the job of bestowing a singular personality upon the guitar.

Addendum: This is a current project, an EPS Performance Standard guitar I’m building for a guy named Brent. Brent is a balls-forward, take-no-prisoners, high octane, Pacific Northwest country rocker. He prefers a guitar with a lot of horsepower. We decided on using Adirondack spruce for the top, for its characteristics of toughness, great tone, and super headroom. With Brent’s aggressive playing style in mind, I braced this top to perform optimally as a rhythm and flatpicking machine. Compared with the other top above, it’s decked out a little more robustly than I would do for a fingerstyle guitar.
The soundbox is now fully built and bound. When you tap and drum on the top, it has an incredibly lively and punchy sound. Brent’s new ride is going to GO, baby. I can’t wait to hear him play it on stage. He has a New Year’s Eve gig, and I promised to have this guitar in his hands by then. I’ll try to post a video clip from the show on the upcoming Blog page.
Another feature you see here is that the inside of the top is sealed with shellac. This is standard in all Edwinsons. The sealer allows the top wood to acclimate gradually to changes in atmospheric conditions, in effect slowing its respiration. This adds dimensional stability to the top. If you’re touring between Tucson AZ and Vancouver BC, you’ll be encountering some drastic changes in temperature and humidity, so the extra protection of a sealed interior is essential.

Bridge and Bridge Plate

Tue, 1 Dec 2009 13:16:58 -0800

The Edwinson Talon bridge is an asymmetrical, two stage, pinned bridge design, and is probably the single most distinguishing visual feature of an Edwinson guitar. I sure do get a lot of comments on it. It’s been called the “batman bridge” and has also garnered comparisons to Ninja weaponry. Stylistically, this bridge may not be everyones’ cup of tea--traditionalists may balk--but most people I’ve heard from express admiration for the edgy verve of the Talon. Either way, it’s become my most identifiable trademark, and I’m sticking with it.
This design evolved more out of functional and structural concerns than for its looks. The Talon is what I call a two stage bridge. The top stage is the front, or leading surface, where the saddle resides. The lower stage is where the bridge pins are anchored, and is carved a good bit lower than the top stage.
In order for the bridge to drive the soundboard efficiently, the strings need to exert the right amount of down pressure on the saddle. On the Talon, the break angle of the strings over the saddle to the bridge pins is set at an optimal fifteen degrees. There’s plenty of down force here, which transmits vibrating string energy directly to the soundboard with very little dissipation.
The carve of the Talon bridge makes it very rigid and strong. The bottom, or footprint of the bridge, is radiused concavely to match the dome of the top, so there’s no one component forcing another.
The bridge is carved from tip to tip to have minimal flexion. It works like a sculpted I-Beam. The bridge itself is acting as a top brace, structurally coupled with everything underneath. The bridge is not just along for the ride. The bridge is the ride, the engine that makes the top GO.
If you could see through the top of an Edwinson guitar with X-ray vision, the first thing you’d notice is that all of the soundboard braces are mechanically linked to the bridge. The talons ride directly over the X. The bass, center, and treble fan braces pass directly under the bridge, where they are jointed into the X. The “lucky 7” braces radiate out from the bridge plate. The bridge, soundboard, and braces are not just an assemblage of parts; they comprise an integrated structural unit. That’s my whole thesis of guitar design, right there.

Now, if you don’t mind, I’m going to pile it on a little deeper and tell you my ideas on the bridge plate. See the photo at the top right: My bridge plate is a two-part lamination of rosewood and aerospace grade carbon fiber. Both of these materials are excellent transmitters of sound vibration. The carbon fiber is the same stuff used to make helicopter rotors.
The rosewood and carbon fiber are epoxied together, and formed to a 25’ radius, exactly matching the doming of the soundboard. The whole unit is only 5/64” thick, but is very rigid and strong.
The whole point to this design is to make a bridge plate that is very low mass, acoustically active, and much stronger than it needs to be to do its job. This plate provides a very stable internal foundation for the bridge, and has the additional advantage that the ball ends of the strings will never chew their way through the carbon fiber face plate, a problem often seen in older, well used guitars that have a typical plain hardwood bridge plate.

The photos above illustrate the process of making a Talon bridge. The sequence goes like this: First, the ebony blank is bandsawed to rough shape. It is then thicknessed, and routed to shape with the plexiglass template. The bridge pin holes are drilled. Then the bottom, or foot of the bridge is radiused concavely to fit the dome of the top. The bridge pin stage is rough-shaped on the belt sander. Then, rasps and round scrapers are used to carve it to final shape.
Finally, the new bridge is sanded to 400 grit, and sealed with four coats of gunstock oil finish, giving it a satin gleam. The saddle slot is cut in after the bridge has been glued to the guitar top. This is one of the final steps in completing the build.

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The Neck, Neck Joint, and Headstock

Mon, 30 Nov 2009 16:00:59 -0800

Recently though, there has been a lot of discussion amongst luthiers and production guitar makers about the wisdom of using a bolt-on neck joint. Bob Taylor was the first major designer to stand out proudly and proclaim the superiority of the intelligently designed bolt-on neck. The current Taylor neck joint is pure genius, and easy to do if you have CAD/CAM technology at your fingertips. Bill Collings agrees with Bob Taylor. Collings uses a serious bolt-on neck joint.
And many smaller shops have enthusiastically been following suit. The bolt-on neck joint no longer denotes a poor, cheaply made guitar. It has been elevated to the state of the art by the best builders in the business.
That’s how I do it now. I use a palm router and plexiglass templates to rough-cut the mortise and the tenon and then carefully chisel down to a tight fit. The neck is attached to the neck block with threaded inserts and hex-drive cap screws. I can now cut the mortise and tenon, and fit a neck in about two hours. The hand cut dovetail took three or four times as long. So I gave myself a 9 cent an hour raise for improving my production times.
There’s no need to glue in the heel of the neck. The bolts do it all. I do use a thin schmear of glue under the fingerboard extension, but that’s just for backup. The idea is to fit the neck to the body perfectly, so all you really need is the two bolts to set the neck exactly in place. The bolts should never work themselves loose, because I apply a bit of white glue to the threads of the bolts to provide a mechanical bond, keeping the bolts permanently tight. If the bolts ever do need to be removed, all it takes is a strong crank with the hex driver to break the glue.
I have engineered several structural features into my guitars that should prevent them from ever needing to have a neck reset done, due to soundboard distortion or other problems often seen in well-used flattop guitars. (see “Soundbox Geometry and Architecture”.) However, one of the more compelling reasons to use a bolt-on neck joint is that if such service should ever become necessary, a bolt-on joint makes that service much easier and less invasive to the guitar.

Since 2005, I have been using a Spanish foot neck block in my guitars. See the photo, top right. The Spanish foot provides a beefy platform under the fingerboard extension to prevent warpage of the fingerboard due to top movement. On the top side, beneath the fingerboard extension, I install a thin, tapered wedge that provides some extra mass, further enhancing the stability of this crucial area.
The main purpose of this construction is that it allows me to set the neck angle precisely. On a radiused-top guitar, you need to be very careful that the fingerboard trajectory over the top is not aimed too high; if it is, the bridge hight will be untenable. The wedge under the fingerboard extension allows me to set the neck angle so that the bridge hight is optimal for good playing action and acoustic integrity. Using this design, the radius of the guitar’s top does not need to be compromised in any way, specifically, by having to sand out the radius under the fingerboard. It’s a bit of extra work to do it this way, but well worth it. Guitar design should be forward thinking; Common structural problems should be engineered out of the design in the beginning, so that expensive and difficult repairs will not become necessary some years down the road.

The Edwinson neck itself is a two or three piece construction, usually with a contrasting hardwood center fill or wood veneer pinstripe. I only use timbers that are quartersawn, because this grain orientation takes fullest advantage of the wood’s stiffness and resistance to breakage. Flatsawn guitar necks are famous for breaking at the headstock; we see at least a half dozen guitars (usually Gibsons) with broken headstocks per year in our repair shop.
The quartersawn, two piece neck construction also provides an exceptional amount of stability against warpage or twisting of the neck. Unseen anomalies in a one-piece neck shaft can sometimes lead to those types of problems. Manufacturers of cheaper guitars may not always grade their lumber carefully, so that’s always something to watch out for.
My favorite neck woods are Honduran mahogany, several species of walnut, American cherry, and white limba. I select neck timbers very carefully for optimum hardness, density, stability, proper grain orientation, and of course, beauty. The neck of a guitar is constantly subjected to 150 to 180 pounds of constant string pull through its working life. The neck is no place to cut corners.
My necks are hand-carved, not milled out. Carving necks is one of my favorite tasks in guitar making. Using spokeshaves, Japanese knives, rasps, sanding blocks, and various measuring implements, I can carve a neck to suit any preference. My standard carve is slim and fast, oval in profile, with a small bit of shoulder on the edges. This carve seems to satisfy modern tastes best, but I am certainly amenable to doing vintage-style neck profiles as well, to suit the player’s comfort.
The standard Edwinson fingerboard has a sixteen inch radius, with a 1 13/16” width at the nut, tapering out to 2 1/8” at the neck/body joint. Again, these dimensions can all be customized to suit your preferences.
I use a two-way adjustable stainless steel truss rod in all my necks. This truss rod uses mechanical torsion to control the straightness and relief in the neck shaft. It is very strong and accurately adjustable.
My standard fret wire is Stewart McDonald #152, a medium-tall nickel silver wire. Many other types are also available.

In The Woods

Sun, 29 Nov 2009 14:12:03 -0800

Every wooden guitar has within its DNA, vast histories of seasons, decades, generations, centuries...the histories of the lives of trees. Every slip, sliver, block and plate of wood has innate within it, secrets that only the the trees themselves have known. Even long past the cycle of the living tree, through the winding of countless seasons, the soul of a tree endures in its remains. The remains of the truly fortunate ones are made into fine guitars, and life begins again. History begins again.

As a guitar maker, I cannot help but feel a great reverence for the woods I use to build instruments. I select them for premium tonal characteristics, workability and stability in service, and of course, beauty. Every effort is made to obtain the finest instrument woods, with the consideration that it should be from trees that are responsibly and sustainably harvested. One can never know for sure if this is the case, but to ignore the issues of conservation and stewardship of the world’s forests will only leave us desolate in the end.

Here at the dawn of a new millennium, our wood resources are becoming ever more slender, particularly in woods that have been traditionally been used in guitar making for generations. Brazilian rosewood, for example, has long been the platinum standard for backs and sides in fine acoustic guitars. Brazilian has been illegal to harvest, export, or import since 1992, when it was added to the CITES Appendix 1 list of endangered species. This magnificent tree has been logged nearly to extinction. The remaining trees are priceless, but they are still being cut down and sold.
It’s bad enough that countless millions of acres of Brazilian rain forest have been slashed and burned to provide grazing lands for enormous herds of methane-belching cattle. Soybeans are another of Brazil’s main exports, and they are grown on vast tracts of what used to be virgin forestland. The soils of the Amazon region are thin in nutrients, and so on a given parcel of land, only a few rotations of grazing or agriculture will deplete what’s there. Then, more forest is mown down, and the cattle and soybeans move on to greener pastures.

The Brazilian rain forest has been called the lungs of the planet. Now, though, those lungs are suffering from near end-stage emphysema. There is only a small percentage of virgin forest left in the entire Amazon region. Brazil’s forest management practices could never be mistaken for wise and conservative stewardship. Profit motives have long strangled the breath out of any argument for sustainable forestry. It is a very sad situation.
Brazilian rosewood can still be found today, and is still obtainable, at very high cost. Years ago, lumber arbitragers and woodworkers saw the writing on the tree trunk, and some of those with the resources bought up huge amounts of the stuff, and put it away in private reserve. A lot of what we’re seeing on the market today is coming from long-held stashes that were bought and put away before the ban. That wood has elevated astronomically in value since the 70‘s. Some of it is stump wood, the remains of already harvested trees. Some of it is freshly cut, illegal, black market wood.
Whatever its source, Brazilian rosewood must be legally certified to buy or sell, and if you are carrying a guitar made with it across international borders, you run the risk of having your guitar confiscated at the customs office, if you lack proper documentation. You might as well be traveling with an elephant tusk under your arm.

While I agree that Brazilian rosewood is the plus ultra of acoustic guitar tonewood, I will not offer it as an option in my guitars, unless I’m completely sure it’s legal, its provenance is certified, and my use of it is not supporting further deforestation. But who knows how many hands it’s passed through, since it was cut down?
Brazilian Rosewood would come at a very steep markup in the cost of a guitar. I’ve seen premium Brazilian for sale at two and even three thousand dollars per set. To my way of thinking, that’s just off the scale, especially when there are so many other excellent options for using non-endangered, sustainably managed, and much more economically realistic woods. If someone absolutely has to have a Brazilian Rosewood guitar, I would be most inclined to send them to a luthier who has a deeply invested stash of it. I’m not that guy. I’ve been building guitars for about ten years now. I got in too late to stake a claim to a piece of the Brazilian pie.

During my brief decade of practice, I’ve seen the supplies of various tropical Ebonies, Rosewoods, Acacias, Mahoganies, and the temperate to subarctic Spruces, Cedars, and Redwoods dry up, or double in price, while the best quality woods become more scarce. And then something in geopolitics changes, the market adjusts, and the supplies open up again. It’s vexing.
Lots of things figure in to the equation, not the least of which is politics. That is, if the country that exports this or that ebony or rosewood is at war with one of its neighbors, or if a whole country has fallen under the sway of profligately corrupt and self-interested leadership, you can expect some wild fluctuations in the supply and price of this or that ebony or rosewood.

Look what’s happening in Madagascar, which in its primal state must have been the very Garden of Eden. If the country of Madagascar doesn’t come to its collective senses very soon, it’ll become the new Haiti, only on a larger scale. A self-cannibalizing paradise, at risk of losing everything, in the richest and most unique biodiversity on Earth. They’re headed that way like a stampede.
Politics is something I’m forced to think about when I’m buying guitar woods.

(pause)

The scarcity of many of the most highly esteemed traditional tonewoods has forced us luthiers to be creative in seeking out alternatives that will contribute quality and beauty to our 21st century guitars. There are many. I seek them out constantly, and have made some surprising discoveries. When you know what to look for in high “Q factor”, you can find all sorts of beautiful, stable, workable woods that serve splendidly as instrument grade material. The Q factor is an arcane grading system that takes into account things like stiffness-to-weight ratio, density and hardness, tonal character, workability, and stability in service. Varying degrees of these characteristics exist in all woods, so if you’re well versed in what is most desirable in guitar tonewood, a great many choices can be made without incurring too much karmic debt.
Whenever possible, I like to buy wood in billets or boards, in person at the Yard, that I can re-saw into sets at home. I’ve taken some chances, spending the whole wad on stuff I’ve never built with before. Canary wood, Argentine Brown Ebony, Monkeypod, Mexican Katalox, and Shedua are some of my best finds. And I found that Limba is an excellent neck wood, as good as the best Honduran Mahogany. Quarter-sawn white Limba finishes out with an antique silver hue, and a straight and true figure. Several species of Walnut are also ideal for necks, if they are sawn at, or close to the quarter and exhibit straight grain and adequate density.
Every piece of potential guitar tonewood deserves to be judged on its Q factor merits. That said, the first thing I look for when I’m cruising through a labyrinth of lumber, is striking appearance. I admit it. Beautiful figure, color, and cut incite me to lust. Unusual figure gets my imagination going. Those are the boards I go to first, the ones that stand out and demand attention. If I find something really nice looking, and it seems to exhibit all the right properties, I’ll spend next month’s rent to add it to my stash.
The guitar pictured at left is built with “alternative” woods. The back and sides are Mexican Katalox, with flamed Bigleaf Maple and Purpleheart inlay and bindings. The neck is California Walnut. Katalox is vividly beautiful, and has a similar Q as top quality rosewoods. The plank I bought for this guitar was only about four and a half inches wide, so I had to make a four piece back. That’s just another creative option, if you’re willing to think outside the box...literally.

This was a fun project, completed on July 4, 2008. This is the Harlequin ECC, inspired by the extraordinary guitars of Howard Klepper. You really must check out Howard’s website. His guitars display masterful craftsmanship, innovation, and genius artistic verve. Howard’s site is packed with detailed information about his design philosophy and building practices. Which is another feature of Howard’s work that I aspire to emulate. Good information, generously shared.

Aside from stalking the isles of local exotic lumber dealers, I also source my wood supplies from a number of dealers who cater specifically to luthiers. Luthiers Mercantile and Allied Lutherie are two longtime favorites, as they have extensive selections of the very best guitar woods, already sawn and rough-dimensioned into sets, ready to build with. Both companies are completely reliable and honest in their quality grading, and their customer service is top notch.
When a client is commissioning an Edwinson, the initial planning has to include selection of woods used, and it can be quite exciting to go online and pick out some very nice wood. Allied Lutherie has weekly specials posted online, which consist of a huge selection of select wood sets in all sorts of species, with pictures of every set. (On the home page, click on “weekly specials”). The weekly specials are updated about every two weeks at Allied Lutherie.
If I don’t have what you want in stock, this is a great way to go. I’ll do everything I can to provide all the information you need, and acquire the ideal materials.

(pause)

My shop partner, Aaron, and I have found some reliable suppliers of high grade top woods, direct from the source. We get most of our Sitka, Lutz, and Engelmann Spruce, and Alaskan Yellow and Western Red Cedar, from companies in British Columbia and Alaska, small operations that cut and mill the wood right there. When we can, we buy split (not sawn) billets, which we re-saw into sets here in the shop, and put away for seasoning until it’s ready to work. At this point, we can’t afford, nor have the space, to keep huge quantities of premium wood on hand, but we always know where to get what we need. And we add stock whenever possible.

Some of the best top woods also have sustainability issues. Two that stand out are Adirondack Red Spruce and California Redwood.
Adirondack Spruce became the premier top wood in the early twentieth century, and is most often seen in fine pre-war (WW II) guitars. Grand old growth trees of this species were almost gone by 1950, and bans were put on further harvesting. Premier guitar makers, notably C.F. Martin, switched to Sitka Spruce as their standard top wood in the late forties, because good quality Adirondack had been logged nearly to oblivion.
The species is no longer endangered, because of conservation efforts and vigorous replanting. But most of the trees alive today have not yet reached their full maturity, and are not big enough to yield high quality standard two piece top sets.
And yet the demand for this wood is still high. Adirondack Spruce became legendary because it is simply one of the best tonewoods on Earth. Adirondack Spruce of decent quality is quite expensive, but it can be had.

Carpathian Red Spruce is another top choice from Eastern Europe. Taxonomically, Carpathian is nearly identical to the Adirondack in every respect. And it is much more abundant, and available at higher quality. This is the first choice alternative to Adirondack. It’s also fairly expensive, as are other European Spruces, but definitely worth it.

California Redwood is another ultra-premium wood that is hard to get and very expensive, but there are suppliers who are cutting and milling standing dead trees, and windfall. I have a good sized billet of it in stock now. The suppliers to Luthiers Mercantile are harvesting only dead trees, which still yield excellent wood. Like Western Red Cedar, Redwood is highly resistant to rot. Trees that passed on thirty years ago still give up some of the best tonewood you’ll ever see.
Allied Lutherie has been selling “sinker” Redwood for a couple of years now, and I’ve used several sets of it. Allegedly, huge logs of Redwood where found submerged behind a dam in Northern California, where they had lain since the 1930’s, perfectly preserved. This is some of the most visually and tonally striking top wood I’ve ever seen. And there’s no karmic debt incurred in using it. (You can see a couple examples of “sinker” redwood on the ECC Consort page of the Guitar Models section.)

To sum it up, I’m always on the hunt for good wood to make guitars with. And if the art of lutherie is to continue past our lifetimes, we have to be sure that the trees continue as well. The trees are much older than we are, and the things that we make out of them should outlive us for a long time.

Someday, I may write a book about wood, and lutherie. Those are vast subjects. If I blather on endlessly, as is my natural bent, it will be a big, thick, heavy book that comes with its own pedestal. It would look nice alongside your back yard sun dial and marble bird bath, next to the Koi pond. I would have this book printed on hemp paper, to save the trees. If it rains, no worries. If the sun fades the ink, so be it. It’s in the Akashic Record.

Perhaps when it’s my turn to receive the harvester’s fell swoop, I will be made into something fine and new as well.

I wish that good fortune to us all.

The Sound Port

Sat, 28 Nov 2009 23:30:25 -0800

Is the auxiliary side sound port in acoustic guitars just a newfangled gimmick, or does it really work? Quick answer: Look in the back pages of Acoustic Guitar magazine, where the luthiers advertise, and count how many pictures you see that show sound ports.
This idea is being enthusiastically embraced and put to use by an increasingly large number of custom builders. A lot of debate about the sound port has been published in the Journal of the Guild of American Luthiers (GAL), and by the Association of Stringed Instrument Artisans (ASIA). Sound ports are showing up like mushrooms after a drenching rain. I’m beginning to think that the only people who don’t believe in the sound port are those who haven’t yet given it an honest try, out of obedience to tradition or whatever.
Ironically, it was two preeminent Classical guitar luthiers, Robert Ruck, and then his friend Kenny Hill, who were among the first to stand up and proclaim the sound port breakthrough. It was mostly classical guitar makers who lit the beacon on the sound port.

What is the sound port supposed to accomplish? The first idea was that having a small sound hole on the upper bout, driver’s side of an acoustic guitar would port some of the guitar’s sound toward the player’s ears, allowing him/her to hear the music better. What a boon that would be for private practice, unamplified performance situations, and also the recording studio!
The second supposition was that porting the upper bout sides would give the whole guitar more lungs to breathe with. It would have more air, more voice, more efficient excursion of sound waves. Same idea as porting a speaker cabinet.
A consensus quickly formed up among builders and players that the sound port was very effective as a personal monitor for the player. But there was more to it than that.
A good few forward-thinking luthiers got on board and started experimenting with sound port design. Many subjective experiments were conducted with ported guitars. The idea grew. Then, some canny individuals got out the testing equipment and microphones, to objectively measure what was actually happening.
Many very surprising things came out of the sound ports in these new, modern guitars. There were numerous reports that the guitar was louder with an open port than when it was covered. People started noticing a rounder, or more spherical sound projection in ported guitars. The words, “organic reverb” and “stereo-acoustic” were bandied around.
Some builders started getting radical with the sound port idea, trying all sorts of ports, large and small, in odd locations, while others experimented with Helmholtz tubes, periscopes, cattle chute baffles, sex toys, and carved wooden speaker horns. More conservative builders usually opted for a small open port somewhere on the upper bout side. That seemed to make the most sense, once the results were in. As the port continued to gain traction, it became one of the significant evolutionary leaps in the 21st century acoustic guitar.
As always seems to happen around the turn of a century, true innovation comes in great surges, every hundred years or so. And here we are. It’s happening again.
The sound port is not a gimmick. It’s an advance whose time has come.

I built the first sound-ported Edwinson in early 2006. The sound port idea was too good to resist, I had to try it. The sound port made total sense to me.
My guts told me that the port’s optimal placement would be in the middle of the upper bout curve, on the driver’s side. That’s primarily a reflective area in an acoustic sound box. My first guinea pig was an ECC Consort model.
For my own skeptical satisfaction, I decided to build that first one with a slider hatch that would enable both open and closed port listening. When I got that first ported soundbox built, I would tap and drum on it with the slider in various positions. That’s when I became convinced that the sound port was for real, a legitimate sound shaper.
The acoustic guitar soundbox should be built to respond like a well-tuned drum. With the sound port in various positions, I could make it sound like several species of drums, just by thumping on the box and working the slider.

When the first ported Edwinson was done and strung up, the results were thrilling. With the port closed, the guitar had a very balanced, even response from high to low, and a healthy amount of volume and sustain. It sounded like a brand new guitar with a lot of potential. When I played with the port open, the voice of the guitar took on an effusion of floral essence. It was like sitting in the middle of a rose garden. I’m not sure how else to describe it. It just became more open, and present. The sound became more fragrant. And I could hear every detail, good or bad, in my playing technique. It was a humbling experience at first. Over time, that guitar kind of forced me to become a better player.
I’m not saying that the difference between open-port as opposed to closed-port sound is dramatically mind-blowing. The essential character of the guitar doesn’t change. It is what it is, only more so.
I kept that guitar in the house for about a year, so I could play it in a bit, and let the voice develop. As the guitar settled into itself, the effects of the sound port became more pronounced. The default position of the slider was open; I became addicted to that sound. I asked other people to play the guitar so I could get the audience perspective. With the port open, I could hear the guitar just as well, standing behind the player, as I could standing in front. With the port closed, the guitar has tremendous forward projection. Other players responded with unanimous praise for the guitar. When I finally put it on the market, it sold very quickly. That ECC Consort also won me some commissions for other ported guitars.
Since then, I’ve built every Consort model except one with either an open port, or with the port and slider. The open port comes standard on my new EFC Falcon model. I’ve included open ports in a few EP Performance guitars as well, but with them it’s almost overkill. In my experience, the sound port works best in smaller-bodied guitars.

Making a sound port with the slider requires some very careful fitting. No wiggle room is allowed. I intend for the slider to be trouble-free for the full natural lifespan of the guitar. With reliable longevity in mind, I now build the internal slider tracks with a high density fiber material. (The first two were rosewood and maple.) The tracks are lined with felt, bedded in epoxy, for a smooth action. The slider itself is a two-piece laminate of ebony or rosewood, which is very stiff and dimensionally stable. The slider button is held in place with two small screws. (See photo above.) If the slider ever needs service, it’s a simple matter of removing those two screws to remove the button, and slipping the slider out of the tracks. If the action needs to be tightened up, some years down the road, all that needs to be done is to glue a couple of thin strips of veneer to the outside edges of the slider, sand them smooth, apply a bit of paste wax, and reinstall for a silky, precise action.
All sound ports are reinforced inside with a high density fiber laminate. For additional stability and style, each sound port is bound in wood.

For some fascinating further reading on sound ports, may I refer you to Tim McKnight’s excellent website. Tim is a luthier of great talent, and his guitars are brilliant and highly innovative. Check out his very well informed take on sound ports, if you need any more convincing. And then have a look at his gorgeous McKnight guitars.

Elegance

Fri, 27 Nov 2009 02:10:54 -0800

You know it when you see it. Graceful lines flow into form, echoing each other in consonance. Contrast and complement in color, figure, and proportion find completeness in harmonious union. No single element disagrees with another. When nothing need be subtracted nor added to the whole, you sense a pleasing balance and rightness. When form and function come together in symphony and become inseparable, you have arrived at the beginning of elegance.

Lutherie is an ideal medium in which to pursue elegance. Elegance is my holy grail. Considering the acoustic guitar in all its aspects, you realize that it combines so many mutable elements that must be carefully joined into a form whose ultimate purpose is to make music. If any crucial element of the material, design, or construction of a guitar fails to show up and do its job, either acoustically, structurally, visually, or ergonomically, that guitar fails the Elegance test.

I like to think of each guitar as an individual entity. When I’m starting a new project, I try to previsualize it as a complete instrument. How is it going to sound? How will it feel? Will it be beautiful and perfectly proportioned in appearance?
All aspects of the form must serve the guitar’s function as a musical instrument, hopefully with notes and lines of elegance in all respects. The pursuit of elegance is the prime directive, ever elusive and arcane though it may be.

When I was sitting here awhile ago trying to think of what to say about Elegance, an odd phrase popped into my head: “The necromancy of wood”. Sounds creepy, but that phrase does capture the essence of the guitar maker’s art: Necromancy is the conjuration of the spirits of the dead, and setting them to the purpose of foretelling and prophecy. (As if they knew...)
The woods we make guitars with are a once living, now dead substance. We luthiers and musicians bring it back to life in a new form, wake it up with vibrating strings, and make it sing songs and tell stories for us. There’s nothing creepy about that. It’s the elegance of life force, moving through transformations of form, with the Guitar as the body, the Musician as the mind, and Music as the soul, all coming together in a synergistic agreement.

I do not mean to imply here that I have found elegance, or that I know anything about elegance, or that my guitars are elegant. I do mean to say that this is the quest I’m onto. I know I can never achieve complete elegance in my work, because no one thing can be all things. It would be foolish to even attempt.

And yet, to not make the attempt would seem even more foolish. What else is the point to being alive?
If you are in command of all your senses, you can never be permanently satisfied, once you’ve seen and felt elegance. It is ephemeral, inscrutable, and teasing, and only comes around when you are open and receptive. Then the moment you notice it with your waking attention, it’s gone off hiding again.
Is it in your coat pocket, maybe? Did you leave it at work, or under the bed at home? Are you carrying it around in your hand, with those car keys you misplaced earlier? It’s so close, you can almost feel it breathing down your neck. The Name of it comes in flashes, but you can’t quite catch ahold of it.
When you can’t stand it any longer, Elegance appears before you, drops the cloak, and stuns you with its naked beauty.

You can’t own Elegance. You can only make yourself available to its grace.