The rocky road to changing your career to luthierie

I am 25 and a college graduate. My reason for contacting you is to seek advice from one of the premier luthiers in the industry.
     I am unhappy with my current profession, and have long dreamed about being a luthier and building/repairing guitars. However, as of right now my current situation with my family does not allow me to attend a school for lutherie, and there are no luthiers where I live.
     My question is regarding learning the craft. I am more than willing to take my bumps and bruises in learning. I have purchased your book on guitarmaking as well as two others, and will be building my first guitar with my father-in-law soon. While he is a retired carpenter, I have no experience with woodworking.
     Can you provide any advice as to how I could begin and progress competently as a luthier even though I will essentially be self-taught? What are the best ways to be able to apprentice under an established luthier? I am willing to do whatever is necessary to enter the field, 

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I'll start with the second question, "what are the best ways to be able to apprentice under an established luthier?" You would have to start by finding one that needs an apprentice to help him in his shop. That would be extremely rare and fortunate, like hitting the lottery. But take a step back first: assuming you could find a working luthier willing to take you on as an apprentice, you need to thoroughly think through the kind of investment of time and money that you would be undertaking. I imagine this would be a daunting prospect, since you have only recently invested a great amount of time and money in the pursuit of your college degree. Are you prepared to make another such large investment? That would be tough, I imagine, putting myself in your shoes. Are you being realistic?

If the number of working luthiers willing to take you on is limited, the number of working luthiers willing to take on, teach a neophyte AND pay any kind of wage is probably infinitesimally small. You would have to defray all your moving, lodging and living expenses for the year or two, or three, that it would take to a) prove to the luthier that you're manually and emotionally competent to complete the required tasks and not become an annoyance or distraction in his studio and b) become productive enough to be able to equitably repay the luthier's time and attention to your education. I do not presume to know what your financial situation is, but I would guess that most recent college grads nowadays would have a hard time making that kind of commitment.

Then, of course there are the luthier schools. That's one way to begin an entry into the field, although learning in a classroom situation is learning in an environment which is quite alien to the reality of the actual trade. The building method you learn in a school is a method which has been adapted to the necessity of teaching many students in a room sharing the attention of usually, an instructor who is only a little more experienced than the students. That is what has come to my attention as the way things are in many of these schools. It is a distant reality from making a living in a custom guitar-making studio. But you do get to complete a guitar or two, and get to be walked through the maze of steps and techniques that are required to complete the task--so it can be a reasonable first step towards your goal.

As far as teaching yourself the craft, assuming you have the not only the resources but the right amount of persistence and commitment hard-wired into your personality, you can assume it's going to take you twice, maybe three times longer to achieve the same level of technical proficiency as someone leaving a professional luthiers' studio as a journeyman. Then you have to build your own market. But I know a dozen people who have done exactly that. You only need to start with a space, a basic complement of tools and start with Chapter One of my book--or somebody else's book. It's one step in a journey of a thousand steps: becoming a successful luthier is akin in time and effort to becoming a successful artist of any other kind.

The joy of guitar making (cont.)

One of the distinctive joys of the guitarmaking profession are the lasting connections you make with wonderful people that last for many decades--and when you discover that the guitar you once made for someone had gone on to make a profound positive effect on a large portion of their lives. Allow me to share some of this exquisite pleasure when someone who purchased my first flamenco guitar over thirty years ago wrote these kind words to me recently:

Bill!

I've checked out your website and am quite impressed:  ¡Qué bien!  Hope all is well and you're enjoying life in the best of health.

Recently I was sitting with my guitar and musing over how well it is constructed and how grateful I am to you for having encouraged me to allow you to make a flamenco guitar by hand for me.  I felt unworthy then, and I still do now; I am forever the amateur, but--to echo your words of thirty (!) years ago "You will feel much better about your playing"--you were right.

I thought you might like to take a peek at the instrument via this photo:

It's in great shape.  I put it back ever-so-gently into its case after every session and keep it from drying out.  

I hark back fondly to the moment when you said, in your gentle way, that you were keeping a piece of cypress on the shelf for the day when I would ultimately make the decision.  It was eventually one of the most satisfying decisions of my life.  Aside from the musical qualities of the guitar, I must admit that I'm still enthralled by the fact that the shadow of my fingers is visible when backlit against the back of the instrument, as you can see in this shot:

At present (age 72) I'm semi-retired. < personal stuff here>

I imagine you must be very busy, but I do hope to get to see you again one of these days.  If I'm heading down your way sometime, I'll give you a holler to see if you would have time for lunch(?), coffee (?), a beer (?), a brief chat (?).   

Bueno, hombre, cuídate....and feel free to use my words and photos as testimonials.

PS:  I was almost forgetting, was this the very first flamenco guitar you made?  I had that impression, but wasn't really sure.  In any case, I proudly possess--in addition to the marvelous guitar--this token of your unparalleled craftsmanship and my abiding appreciation:

Who was José Yacoppi?

In short, José was a Spanish luthier who escaped Spain's harsh dictatorship of the 30s, 40s and 50s and established his craft in Argentina. Interesting guy, fascinating life. Fascinating personality. Here's his story:

When he was a boy, José Yacoppi learned that in life, you don't need much to survive. Every time his father--a guitarmaking luthier like him--was chased by Franco's men in Spain, the Nazis in France and the war in Europe, he learned that a workshop had to fit into a valise, and the life of an entire family could depend on one guitar. Every time they had to move all they had to take with them was a finished instrument so that José could show his art and get supporters until he could begin anew. In 1949 he arrived in Argentina and opened his shop on quiet San Fernando street.

"My 84th birthday was on the 28 of December [2000]. People call on the phone and say, 'yes, can I speak to José Yacoppi?" and I say, "yes, speaking." They're surprised. They don't say it, but I can listen to the tone of their voice, "but how can that be? He's still alive?"

It's best you know from the start: the best of Yacoppi, after his guitars, is his black humor. He's been exporting guitars to Japan at a pace of 25 a year. "Look, I know there are a bunch of my guitars out there, and when I'm dead, their price is going to rise. Outside Argentina, my guitars sell for high prices. Do you know Eric Clapton? He bought a Yacoppi in Germany three years ago and paid seven thousand dollars. And at the Sotheby's auction house in London, he knocked down a 1950 Yacoppi after paying ten thousand dollars. I wish I had one to sell. It's that in 1950 I was very young, and what was I to guess, that my shop would eventually become so highly regarded. I also never thought I'd live so long. Look, once I even made a vihüela, the grandmother of guitars, that one over there..."

He walks to a showcase and takes out a vihuela, a large instrument studded with mother of pearl.
"The amount of work on this is so monstrous, so huge, that I hardly can believe it was me who did it. Once I took it to Europe. I told myself, "I'm going to kill with this one." He took it to Sotheby's and someone there said, "Oh, how pretty. Who made it?" "Me." "Oh, but you're alive." I say, "Yes, I'm alive." And he says, "Oh, no, you've got to be deceased." I told him, "I'll shoot myself and come back."

Jose Yacopi passed away on the 11th of August of 2006.

Jose Yacoppi

Classical neck pitch

What do you think about the traditional spanish way of having the neck slightly sloped forward by 2-3 mm?

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As to the "Spanish" tradition of sloping the neck forward (I didn't know that it was uniquely a Spanish tradition), it's supposed to provide ample string clearance to avoid buzzing during vigorous playing without having to make the bridge massively tall. If the guitar is to usually play quietly for an audience in a small room it is unnecessary. I've learned that one must be careful to pitch it no more than 1.5mm at the nut, or impossibly high action may result.

9/12/11 Revision: I hasten to modify these remarks because they proved to be misleading: by stating the concept of "pitching the neck forward" I really needed to clarify that this effect can be achieved in a number of valid ways: by 1)  tapering the fingerboard (so it begins thicker at the nut and ends thinner at the sound hole end) and then gluing it down to a neckshaft which is perfectly level with the perimeter of the soundboard--in which case the solera must be perfectly flat from end to end (and rigid enough not to distort or sag during the building process) and 2), keeping the fingerboard at a constant thickness (usually 1/4-inch) and tapering the neck-arm of the solera so that it is 1/16-inch thinner at it's end, which should coincide with the nut location of the neck. This the entire neck shaft will be induced to pitch forward (or upwards) by 1/16-inch and be fixed in that orientation when the back is glued on. This requires that you hollow the upper transversal face brace by about 1/32 to accept the diving fingerboard-fingerboard end (draft it out to ascertain the correct amount).

There is yet a third scheme which is to keep the solera un-tapered, and thus the neck shaft level with the soundboard perimeter, while keeping the fingerboard uniform in thickness along it's entire length. This requires however, that you induce a 1/8-inch to 3/16-inch dome or swelling in your soundboard at the bridge location--by curving all your fans and bridge-bottom. This will create a favorable action-height by raising the bridge rather than "pitching the neck forward."

Julian Bream's Bouchet bar story

Regarding classical guitar construction, may I ask you your opinion about using a transverse bar under the bridge instead of the bridge block--like Bouchet ? [the "Bouchet bar" is a large, tapered transverse brace that Bouchet placed horizontally across the soundboard, directly under the bridge--it was characteristic of his work]

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I can best answer your question with an anecdote told to me by luthier Jeffrey Elliott many years ago (I hope the details are still accurate)--Jeffrey was accompanying the great Julian Bream on one of his occasional US tours. Bream often invited Jeffrey, whom he regarded highly, to accompany him in his US travels, to keep an eye on the several instruments he brought with him on his tour.

One day he told Jeffrey that he was dissatisfied with the tone of his Bouchet--in comparison to that of his Romanillos--and said that he thought it was the Bouchet's long transverse bridge bar, missing on the Romanillos, that made the difference. He asked Jeffrey to take it out. At first Jeffrey was very hesitant, given the value of the instrument, but Bream persuaded him, saying that he would accept all responsibility should the venture prove disastrous.

So in a hotel room and some improvised tools, Jeffrey removed the strings and proceeded to break up and carefully remove the rather large Bouchet's transversal bridge bar. Well, the upshot was that the venture was not disastrous, indeed it was a great success, according to Bream--and Jeffrey--the loss of the bar transformed the instrument, it's voice opening up dramatically. His account effectively kept me from ever experimenting with the Bouchet scheme.

Doming the top---and the bridge?

My name is Andrea and I live in Italy. I bought your marvellous book many years ago, but only recently I decided it was time for me to build (try at least) my first guitar. After reading again your book I have a doubt: the soundboard is domed but, as far as I can see, there is no mention about shaping the bridge accordingly. Is it because the doming is so little in the central area that a flat bridge is correct ?

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While my building technique relies on a domed soundboard, it does not call for a bridge with a curved base.

Soundboard doming schemes vary widely among builders. It depends on what each individual luthier has learned from their teacher or how they individually perceive what the consequences or importance of doming to be. Clearly there is no rule or law in this regard.

In your country, luthiers of high reputation construct their tops differently. For example, Mario Garrone of Piemonte and Mario Rosazza of Roma build their tops completely flat with no doming at all, while Gabriele Lodi of Modena, in fact, does dome his soundboards.

Among builders who build their tops completely flat, obviously their bridges are flat also. But among those who dome their tops, some of them attempt to match the curve of the base of their bridges to match the curve of the soundboard at the bridge location. But some, like myself dome the tops, but choose to leave our bridges flat.

I can't tell you what justification the others have for these choices, you would have to ask them.

But as for me, I dome my top because I am certain that in itself this adds rigidity to the top plate, and allows me consequently reduce the thicknesses of the top plate and heights of the braces. I believe in minimal adequate structure, as you will quickly learn if you read my other posts on this blog.

Conversely, I would expect that if I was building completely flat, I would feel constrained to increase the thicknesses of the plates and heights of the braces to compensate for the top's relative weakness in a flat state.

I don't see much point in going to the trouble of hollowing the base of the bridge (and don't forget now, your bridge block must also be made correspondingly curved by the same amount in the opposite manner if you wish to preserve the bridge's contour when you are gluing it to the top).

All this is seems unnecessarily troublesome to me, particularly since you would have to be able to ascertain with precision the extremely slight curvature that is developed along the few centimeters of the bridge's length. Unnecessary, because in any case, it is my conviction that since all the elements of the soundboard are essentially elastic to some degree or other, the effect of the string's tension upon the bridge is too drag it into a new contour regardless of whether it is flat or curved.

I believe that string tension is enough to distort whatever laboriously-determined curvature was imparted in the first place. Indeed, I have seen how the string's torquing forces over time inevitably cause the bridge to slightly dip in the front and slightly bulge in the back on a good, lightly-built guitar. I would not be surprised that the tiny bit of curve imparted to the bridge would be long-lost by that time.

But that is my reasoning and thus my choice. All the others are welcome to their own traditions, rationale and experience. Great guitars are possible whichever scheme you choose.

Headblock puzzle

[On a steel string guitar] If the neck is to be set at an angle to the body, and the body is arched to match that angle so the fretboard can be glued to the top, then why does everyone draw a headblock with a 90 degree angle between top and side? It seems to me if you do that, when you glue the fretboard down, you’ll be mashing it and the soundboard against a block of mahogany that is on a different plane. The obvious solution to me is to angle the top of the headblock. But, when you discuss fitting the neck to the body, you stress the importance of adjusting this angle at that time, so it seems the obvious solution to the above problem isn’t quite possible. How do you resolve this?

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Your perception is correct, as far as it goes.

If you draft everything out, side view, on paper in full size, you'll discover that for the action to be optimum and the saddle height to be optimum, the neck needs to be tipped back by a small amount, relative to the plane determined by the perimeter of the soundboard. Thus the end of the fingerboard must rise as it pivots upward, beginning from the point where it meets the front edge of the soundboard. The nut end of the fingerboard rotates downward, while the saddle end of the fingerboard rotates upward, pivoting right where the neck meets the body.

However that rise, measured over the width of the headblock, is exceedingly tiny--barely a 1/64-inch. Indeed the fingerboard-end keeps rising to its terminus and the soundboard must also rise to meet it--just above the soundhole. Thus the upper transversal face brace must be arched about 1/16-inch--generally enough to raise the soundboard under the fingerboard end to just reach it--on a 14-fret guitar--or around 3/32-inch on a 12-fret guitar.

What you propose, angling the top of the headblock to account for the rising fingerboard end is technically correct--assuming that you've kept the rest of the headblock strictly perpendicular to the workboard. But that's not the only way to go about it. If you leave the headblock square where it meets the soundboard, it will drive the front of the soundbox to a small tip-back relative to the workboard--which should match fairly closely the amount the heel would otherwise have to be trimmed later to achieve the required tip-back of the neck.

So take your pick--slant the top of the headblock by 1/64-inch and expect to trim the heel later to set the neck angle; or keep the top of the headblock perpendicular and let the headblock naturally tip back by 1/32 from perpendicular (to the workboard) and dispense with the heel-trimming neck-set procedure later on.

The Urge to Inlay - II

An old student of mine from the Netherlands commented on an earlier post. He writes,

Hi William,

After your last blog about The urge of Inlay I just got to let you know that I just returned from a little trip to Berlin, and we visited .... the Bauhaus Archiv! Of course I knew about Bauhaus, its connections with the De Stijl group in this country, but to be completely immersed in it. It was a TRIP!! Beautiful pottery and the metal workshop designs are breath taking in their powerful simplicity. Forget about superfluous embellishments, just the elementary shapes.

I must say that I am starting to recognize the Bauhaus approach/ideas not only in your guitar design, but especially in the efficiency and economy of combining design with technology or rather craftmanship. Yeah, I guess I am slow. But you did not tell me that in the tutorial I was actually signing up for a slow but prolonged Bauhaus brain wash...

Thanks for the eye openers!

Best,

Pieter

Why not just screw the neck on?

A correspondent asked me why I prefer to use a neck joint system that relies on barrel-bolts. He writes,

I wouldn't use barrel nuts at all. I would take a hanger bolt like this: I would drill a slightly oversized hole into the neck heel, chop the hanger bolt to length, and thread it in, locked down with epoxy. The epoxy will allow us to use an oversized hole so as not to put any significant compressive stress on the neck (we wouldn't want to risk a stress fracture, either during installation or 100 years from now). It would still "thread" into the neck, but it would be a loose threading and the epoxy will permanently lock it in place. Then I would use a nut inside the guitar body. Inside the body, I would use a spherical washer so that the bolt alignment/neck angle is not critical. I think this is a very unconventional arraignment and would probably have luthiers worldwide looking at us with scorn, but aside from that I think it's very simple and workable.

Screwing the neck into the body is a worthy endeavor. But...

NEVER fool yourself that what you've just invented hasn't been done before

in the guitar world. There's almost a thousand years of "prior art" in the stringed instrument universe. There's very little low-tech guitar luthiery advances you can think of that haven't been done previously--a dozen times.

Regardless, guitar-improvement hubris affects us all at one time or another. It affected me when I devised the barrel bolt system--a reaction to my teacher Gurian's pinned mortise and tenon--which was a reaction to Martin's tapered dovetail--which was a reaction to the joint-less Spanish Method.

You're free to react to my barrel bolt system--be my guest! You won't get any flak from me, or any luthiers for that matter--they don't know any better. But you will get flack from formal cabinetmakers. My old friend Ian Kirby, instructor at the Royal College of Cabinetmaking told me when I brought up the subject, that one of the Ten Commandments of woodworking is "never screw into end grain." HE would look upon your idea as inelegant and hazard-prone.

But not me. Because his field is cabinets. Because I know that screwing necks on has been a luthier tactic since luthiers learned to cast lead or iron screws and bolts. Lag screws appear on lutes made during the Late Middle Ages and Renaissance. Taylor Guitars uses cap-head machine screws that screw into wood-threaded inserts inserted into the end-grain of the heel. Most luthiery schools teach two neck joints, tapered dovetail and neck screws. Period.

When I devised the barrel bolt system, advisedly, I never announced or claimed first use. And guess what? I had been using it for years when I discovered that my old partner, Michael Millard of Froggy Bottom Guitar fame, had devised it quite independently on his own for several years before also. Exactly the same arrangement. For exactly the same reasons:

1- the pinned mortise and tenon system was difficult, tedious and complex. As is the tapered dovetail.

2- we hated the look of two unartful nuts on the headblock staring at you from the soundhole.

3- we were concerned about the long-term effects of screwing into end grain, or the short-term effects of threading a screw into the endgrain heel.

4- you could get the barrel bolts at the local hardware store. You don't have to turn your own wooden taper pins.

5- having to change the neck to body angle throws bending stresses onto the screws, which throws strain onto the wooden parts. The rotating barrel in the barrel-bolt system solves that problem.

I confess, your selection of the spherical washer as a solution to 5) is a clever hardware choice. And your idea of drilling an oversize hole in the heel and casting epoxy threads didn't occur to us, but you'd have to be pretty confident that the entire epoxy plug wouldn't just pull out someday.

Your wanting to invent your own system has a noble heritage, so I won't be the one to squelch it. I'd experiment with how much force is required to pull out the epoxy plug first. Then go ahead--be my guest. Build your own guitar with a personal neck-attachment system that you think best fits your own priorities.

The Urge to Inlay

I love the Grizzly tool catalog, and I'm delighted to see that like myself, Grizzly's president is himself a guitarmaking devotee. I often leaf through the Grizzly catalog's pages, salivating over the 18" wide-belt abrasive planer which I probably should get to replace my rickety 35-year old homemade 14" filetier, Galloping Gertie. Mr. Grizzly's guitar work is proudly displayed on various places around his impressive and weighty catalog, along with huge Gear-Head, Cam Lock Spindle, Gap Bed Lathes. I own half a dozen much smaller Grizzly stationary power tools myself, and for the price, they give remarkably good service. And I absolutely LOVE the bridge pins he supplies" and have been using them exclusively. The ones with the abalone dots surrounded by tiny brass rings. They're lovely. I hope he keeps supplying them forever.

Above is an example of his painstaking work, as displayed in a personal page on his online Grizzly catalog. Every time I look at it, it begs me to ask, Mr. Grizzly president, kudos for your ambitious effort, but: what on earth does Tutankhamun have to do with guitars? Okay, images of cowboys on horses surrounded with cactuses riding into the sunset--or even hula girls playing ukeleles. I can kinda see the connection. They've decorated guitars since the early 20th century. But an 18th dynasty Egyptian pharaoh?

To me, this speaks to a peculiar urge that is so prevalent in my field. The urge to Inlay. I'm intrigued by the urge to apply seemingly random images of all sorts on guitar surfaces. What do these disjointed images add to the already-elegant and sensual form, the iconic shape beloved around the world for a thousand years? I marvel every time I view photographic displays of fingerboard inlay masterpieces--with the strings removed of course, so the pesky strings don't interfere with our clear view of the real masterpiece.

Well, to me, the guitar's pristine form is as much awesomeness as I want to behold at one time, without distraction, thank you.

To varnish?

Quick question. Is the hype about Varnish finish true? Does it make a big difference in sound? Is the finish on the top only?

Oil varnish is indeed a superior instrument finish for not only it's film hardness and high solids content but also–when expertly applied–its rich, warm glow. It's all but outdated in the guitar world, however: I know of only one maker currently oil varnishing his guitars. The main problem is that it takes several days to dry, because it dries by oxidation--slowly. Lacquer dries by evaporation--quickly. Not only does varnish's slow-drying properties make it time-consuming to apply, but problematically, as it dries it can accumulate floating particles in the air sticking to it. So it requires a scrupulously clean application environment. On the other hand, lacquer skins over in minutes, repelling any floating particles. You can theoretically apply a lacquer finish in a day--but it takes several days for an oil varnish coat to fully dry.

As far as whether it is "better" than lacquer, one would have to define "better," of course. People are always asking me, what's better? Better how? In film strength and durability? That can be judged objectively, and the answer is...yes, but only marginally. In sound? Better in appearance? That cannot be judged objectively. How would you determine that? Does it result in better sound? By which criteria? By whose criteria? How do you set up a test? How do you evaluate such a test?

Now as far as the hype of varnish's "superior sound," it's reputation comes, no doubt, from its traditional high-class associations with the bowed instrument world--the playground of the elites. When a violin or a cello is played before varnishing, that is, while its "in-the-white," they usually display an unpleasantly harsh, strident and scratchy sound. The application of varnish notably "smoothes" the sound out, turning scratchy into beautiful: thus the age-old, esoteric mystique of varnish in violin culture. So it must also be good for lowly guitars too, eh?

But violins are from Mars, guitars are from Venus. Arm-driven violin bows dump massive amounts of energy onto the strings–continuously. Your finger tips apply only modest amounts of energy into your guitar, a bit more by the action of leverage if you use a pick. Accordingly, the rule on a guitar is that you DON'T want the finish coat to dampen any portion of the guitar's response, the applicable rule being "less is more." On the violins however, you want the finish to dampen portions of the response lying in the unwanted frequency bands. The function of the finish film in perfecting the violin's response is a significant factor in its world, whereupon the major issue of the finish in perfecting the guitar's sound is "how little can I apply and still be able to polish it out?"

Interestingly, this is only one of several preachy "violin lore" dictums that have mindlessly passed on into the guitar world. The most glaring one is that if f-hole archtops are the thing for violins and cellos, they must be good for guitars. Don't get me started on that: I'm still waiting for an arch-top guitar to equal a flat top in loudness, sustain, and tonal complexity. But that's just me.

Oh, and then there's the "remove and replace only one string at a time" canard which I'm often asked to explain. Clearly on a violin if you remove all the strings at once, the bridge falls off, and the sound post can drop, too. But I'm yet waiting for someone to give me a persuasive reason for following that rule on guitars.

Someday the guitar world will get over its poor-cousin-to-the-violin inferiority complex.

Michael Kasha's legacy

Florida State University physical chemist Dr. Michael Kasha created a stir in the guitar field thirty-five years ago when he proposed a systems-analysis approach to the resolution of the age old dilemma of structure vs. tone in the guitar. Dr. Kasha is Distinguished University Research Professor at FSU, an elected member of both the National Academy of Sciences and the American Academy of Arts & Sciences--the Oscar people.

The traditional specifications for classical guitarmaking were established for subsequent generations of makers and players to follow by the venerated nineteenth-century Spanish luthier Antonio de Torres (he died about the time of the American Civil War). Torres assembled into his new design what he considered the best of all the various ideas that were being used in Europe during his time. The combination of his chosen scale length, soundbox size, bracing pattern (which consisted of a series of long struts under the bridge) and even his decoration scheme became the "classic" guitar which we see today all over the world.

In a nutshell, Kasha proposed that under the traditional system, the long stiffening bars under the top unduly restricted the soundboard's movements. Instead, he proposed a multiplicity of no less than twenty short braces fanning out in what appeared to be a peculiar, yet seemingly purposeful pattern around the bridge. Second, he proposed an aluminum stiffener imbedded into the heel to keep the body and neck more integral and less flexible relative to each other. He also proposed an assymetrically-shaped bridge which purportedly coupled the bass and treble components of the string's signal more efficiently to the guitar. Unfortunately the lopsided Kasha bridge, which became the most visible and distinctive feature of the system, gave the guitar face a comical sneer, which perhaps contributed to the guitar's lack of acceptance in a rather conservative and hide-bound market place.

As a scientist, Dr. Kasha sought the approval of other scientists and proposed the system before physicists and acoustical engineers during at least one convention of the Acoustical Society of America. Ordinarily, musical instrument acoustics is given faint attention at these gatherings: the preponderance of the interest goes to papers treating submarine sonar ranging systems and nuclear-explosion detection devices for the Defense Department. So, even within the faint attention afforded to instrument acousticians, Kasha's paper was pretty much ignored, for what was explained to me then as it's shaky science: unsubstantiated claims, no supporting data, and the killer: even though a celebrated chemist, Kasha was not one of the acoustics boys.

Kasha enlisted the support and interest of the late Richard Schneider, the Kalamazoo, MI guitarmaking genius. Schneider became for a considerable period of time the main proselytizer of the Kasha system and a fountainhead for a small group of young luthiers and concertizing guitarists that got on board in an attempt to promote and popularize the system. Dismayingly, they were often damned with faint praise, and even treated by some traditionalists over the years as if they were a silly cult.

Several of the later samples that Schneider built, utilizing Kasha's system reportedly were, indeed, impressive sonically--but not extraordinarily so. Even this limited success was attributed not to Kasha, but to Schnieder's personal skill and intuition which, it was believed, could extract excellent results from whichever scheme he might set his mind to. Nonetheless, the proponents of the system claimed a sea-change of improvement to justify the bewildering complexity of the new system.

Listeners and builders simply were not sufficiently impressed to change their ways. Hence, the faint praise. Seemingly, this just stiffened the Kasha clan's resolve: they were determined to pursue the system, hoping to refine it until it fulfilled the promise that they eventually expected from it.

Thirty years later, very little interest remains in the Kasha approach, not that a great deal of interest was ever elicited from the general musician/guitarmaking public. The Kasha system is simply not a subject of discussion or interest in the field any more. Apart from the merits of the system, one of the major factors that contributed to the decline in visibility of the system was the fact that in his later years, up to his death, Richard Schneider stopped using the system. So the main driving force behind the system's general acceptance pretty much died with him. The coterie of younger builders that worked with Richard have gone on to devise personal variations of their system, or just adopted one or two features of the entire system and returned to more traditional forms for the rest of their instruments.

At the height of its interest during the mid-70s, Richard Schneider was an indefatigable proponent of the system and a tireless advocate. He came up to me after showing me a Kasha guitar he called "Wanda" (I thought it a peculiar name at the time), I played it and simply could not hear it well in the large, noisy room. I greatly admired Richard on a personal level, so I felt compelled to say something positive...so I praised it's stunning workmanship. That wasn't the response he was looking for. Visibly irritated, he glared earnestly at me and said: "You're looking at the future!" and turning on his heels, walked away into the crowd with it.

It was this manic energy that drove some to call his interest obsessive, even overbearing. He reportedly dogged this century's greatest grand master of the guitar, Andrés Segovia, to get him to evaluate a Kasha-system guitar. The version of the story that I heard was that the Great One--who rejected modernity in all its forms--resisted what he must have considered his annoying entreaties, but finally consented to try it, just to appease the persistent guitarmaker. Segovia played it and immediately rejected the guitar out of hand.

The rejection just increased Schneider's sense of conviction. Convinced that Segovia's eventual approval would insure the system's universal acceptance, Schneider kept dogging the old man over the next several years with progressively-improved versions of the instrument. Segovia finally accepted and retained a copy. It's unclear whether he liked it or simply that he wanted to put an end to the whole matter. It's my understanding however, that Segovia, up to the date of his death, never performed in public with it. Yet Schneider and his followers believed that they had nonetheless won a major victory for the cause.

About the same time, the victory was counterbalanced by an embarrassing setback: a botched effort to bring the system to the mass market. On the weight of his own considerable reputation, Schneider was able to persuade one of the oldest and largest guitar-making factories in the world, the Gibson Company, to build and market a Kasha-braced instrument. In a conversation with me, Schneider blamed the ensuing fiasco on Gibson marketing executives who insisted the system be inaugurated to the mass public on a line of steel-string folk guitars, rather than on nylon-strung classic guitars, which was what Kasha had originally intended. Regardless of what Schneider later called (in conversations) the impulsive and premature decision to misapply the system, Schneider indeed participated closely in the design, tooling, production and marketing of the Gibson Mark steel-string guitar. The production of the Mark guitart was vastly more complex and difficult than the production of ordinary guitars. The result was a certifiable flop. The Gibson Mark guitar was heavy, ugly and an utter failure sonically. It also suffered from all the worst aspects of guitar mass-production: bad glue-ups, poor materials selection, indifferent workmanship, bad action adjustments...in short, a complete fiasco. Subsequently, Richard tried valiantly to put the whole matter behind him.

Kasha's legacy remains as simply an earnest attempt to redesign the acoustic guitar, in a laudable effort to bring science and art together. Unlike instruments with a far simpler anatomy--such as violins--the guitar's fantastically complex signal response defies easy analysis. I believe that Kasha's attempt to create a system to bend the guitar to his will and Schneider's effort to promote it, was perhaps all an exercise in self-delusion. It was a failure in many ways, a failure most notably assisted by the hide-bound culture of the classic-guitar field at that point in time, not to speak of the peculiar appearance of the instruments themselves.

The Kasha system still resonates occasionally when guitar lovers who hear about it for the first time, are attracted by the "product-differentiation-in-the-marketplace" look of the guitar and not knowing the particulars of its history and the personalities involved, ask for my take on it.

Although my take is that the system fell far short of it's sales pitch, its not to say that the guitar's traditional acoustical anatomy cannot be made more efficient. There are today a small number of builders who are, as we speak, dramatically wringing remarkable changes in the guitar's response. Alan Chapman and Greg Smallman are two builders whose work I'm familiar with, who are achieving impressive results with graphite-reinforced lattice-bracing systems and beefed up soundbox structures. They and others following their footsteps are now consistently producing classic guitars which can aptly be termed "cannons.". The best and brightest guitarists are starting to flock to this new breed of builders, and more and more makers are starting to emulate their success. No button-holing or proselytizing has been necessary. It seems everybody is stealing the idea from them--the sincerest form of flattery.

But with everything that is gained, usually something is lost. For me the warmth and intimacy of the traditional sound is lost on these new shouting instruments, much of the gestalt is gone. The traditional anatomy has enough value for me to only venture tinkering peripherally with it, since I, for one, love it as it is.

Guitar abuse

Do you do any extra reinforcing on the side in the bend of the cutaway? I was thinking that the bend itself provides some structural rigidity in one sense but that it could also be a weak spot if the guitar were dropped.

Here's my perspective: It's not your responsibility to make the guitar drop-proof. You're making crystal goblets, not cafeteria tumblers. You're not making a back-packing guitar either. What you're making is a delicate eggshell optimized for sound, not rugby. Any treatment other than taking it out of the case, playing it, and putting it back in the case is abuse.

Look at that grain!! IT'S AWESOME...!

I'm constantly receiving unsolicited mail from tonewood suppliers, with pictures of guitar sets like the one above, usually with stratospheric prices attached. It makes me pause and wonder if it would be a good marketing move to have my next guitar look like a Rohrschach test.

Naah, I'm more of a form-follows-function guy. Bauhaus aesthetics was thoroughly drilled into my head during my early years in art school. Now, when considering an artistic decision, I think back at what my Form and Structure instructor would say. In this case, I can hear him ask, "is a guitar's pure, highly-evolved form so deficient, so uninteresting, that it needs all that pretty stuff lathered onto it?" I know he'd berate all those objet d'art guitars pictured in those upscale wet-dream guitar magazines, dripping with glistening pearl and abalone acanthus leaves and Parthenon scrolls, all slithering up and down the fingerboard and headstock--and drooling over onto the back and sides. He'd berate them in the same way. It's so...it's so...nineteenth century! A guitar's pure form isn't beautiful enough for you? Noo--you gotta trowel on some of that pretty stuff. NOW it's really pretty.

Well maybe the Rohrschach wood is okay 'cause--well, it's nature, isn't it? If its from a burl--like the above--its really cut from a monster knot the wood grows around a wound, or just a vegetable cancer growth. Not exactly the kind of Nature you'd like to warm up to. Or if its wild wood from a stump, it grows that way so the tree won't tip over when the wind blows. So that means all that skittish tension wood should be built into something that absolutely-positively must be dimensionally stable? A fine recipe for an eventual wall-hanging!

When wood gets to look like that sample above, its fiber structure gets to approximate something like oatmeal: nothing like the orderly array of long, relaxed fibers that you imagine all those mathematically-organized harmonics would choose to travel across, unimpeded and unhindered, hither and fro.

No, I know it doesn't do that. I'm just imagining. But I remember what happened in my early days when I thought it would be bitchin' to have crazy wood all over my guitar: I had to super-glue 10,000 splits in the side after bending them, and then several years later I had to replace the back after the plates cycled through several climate changes and seasons, when that cool oatmeal-wood actually began to look like lumpy oatmeal. A bitter lesson: that very kewel oatmeal-wood is not just awesome--it's big trouble.

Are luthiers fetish-makers?

fetish |ˈfeti sh |nounan inanimate object worshiped for its supposed magical powers or because it is considered to be inhabited by a spirit.• a course of action to which one has an excessive and irrational commitment : he had a fetish for writing more opinions each year than any other justice.• a form of sexual desire in which gratification is linked to an abnormal degree to a particular object, item of clothing, part of the body, etc. :Victorian men developed fetishes focusing on feet, shoes, and boots.ORIGIN early 17th cent. (originally denoting an object used by the peoples of West Africa as an amulet or charm): from French fétiche, from Portuguese feitiço ‘charm, sorcery’ (originally an adjective meaning ‘made by art’ ), from Latin factitius (see factitious ).

Lies, damn lies and acoustics I

What makes a guitar sound good?

For the interested musician or dedicated guitar-making student who seeks to get to the truth about the instrument's nature, the scientific and the popular media have, alas, provided only a muddy minefield.

The field of guitar acoustics has become populated both by sincerely interested speculators who, with little fear and with remarkable facility, pass on untested information as if it were gospel; and a few real experts who usually confine their comments to the scientific literature.

In the scientific journals and professional publications, you will find that when researchers make even the most modest observations, they make them with guarded hesitation--elaborately qualifying them with an eye to the strict rules of the scientific method. They will make their observations about the guitar's behavior only from what is clearly evident from laboriously-generated data. Not a sentence more, not a period less. Thus, guitar enthusiasts searching for enlightenment in the turgid prose of formal acoustical papers (even those that can actually follow them), usually come up with a dry hole.

Guitar makers, on the other hand, have no such hesitation--all too often, I catch them making shameless claims about their guitars in the popular media--purposely allowing the impression to remain in the public mind that the keys to the mysteries of guitar acoustics are well in their reach. Perhaps that, too, is to be expected: many of them must find it irresistible to create impressive sounding, though ultimately vacuous, impressions of their products. After all, who will know the difference?

It is difficult to sort out the wheat from the chaff in this matter because even instrument makers themselves (and who else can we turn to?) have created and perpetuated a body of acoustical mythology that pervades the background of acoustical inquiry, like noise. Instrument makers, for all their intuitive skill, usually make very, very poor sources of hard information on guitar acoustics. The vast majority is not trained in acoustics and I'd hazard to say that only a handful could actually define "sound" or explain the behavior and effect of sound waves traveling in air or through solid objects. How many are driven by a profound--or even working understanding of point sources, sound pressure, resonance theory, acoustic declension, near-field holographic interferometry, acoustical damping or standing waves? Hardly a one, myself included.

In truth, they should only be asked about what they do best: create charming cultural artifacts by following patterns and practical strategies passed on to them by their teachers, duplicating the work of past masters whose work--marvelously accomplished, skilled and intuitive work--offers up a treasury of effective problem-solving solutions. To this they add the wisdom gained from their own painful trial and error past experiences--and then, each adds subtle variation to this acquired methodology, the product of their personal inclinations and individuality.

As if this wasn't impressive on its own merits, I nevertheless see too many "guitar authorities" ducking difficult questions by wrapping themselves in the mantle of vague acoustic-science terminology, gulling the un-initiated among us into thinking that they have the sound thing all wrapped up.

For instance, a prominent guitar-making textbook put forth a popular misconception among traditional builders here and abroad: that, starting at the bridge, the guitar creates sound by waves "radiating" away in all directions toward the edges of the guitar, not unlike the effect that follows the dropping of a pebble into still water. That ignores, of course, the fact that the string is coupled to both ends of the guitar, the much-ignored neck as well--making it a significant sound source at certain frequencies. In reality the guitar top--nay, all the guitar's surfaces--wobble and heave in all sort of deceptively fitful ways, in response to the energy interactions occurring between the guitar and its vibrating strings. The explanation also ignores the fact that the guitar's vibrating wall surfaces account for only a fraction of the its total sound production. Yes, the guitar is a fantastically complex vibrating object which defies simple description--and simple descriptions like "sound emanates from the bridge like a pebble in water" can only be misleading at best, cynically self-serving at worst. 

Yet, I have read in guitar magazines solemn assertions by experienced guitar makers and observers that sound waves travel to all areas of the soundboard via its braces. I call this the "highway" model. For all intents and purposes, though, braces are invisible to the several major low-frequency guitar vibration modes that have been identified on a guitar (there are too many high-frequency vibration modes to individually identify). Then there is the "bass-treble side" model which divides the soundboard into discrete bass and treble halves (each "under the control" of the corresponding bass and treble strings immediately above them). In this scheme, alterations to the bass and treble response of the guitar can be directly manipulated by somehow fussing with or changing the thickness or height--or number--of soundboard struts in the corresponding area. They talk like they can put treble and bass controls on an acoustic guitar by fiddling with the "bass and treble sides" of the soundboard. My acoustician friend tell me that's a ridiculous myth, too.

We have also seen the soundboard likened to a trampoline, or requiring its individual parts to be tuned to the notes of a chord so that the instrument's response will take on the sound character of that chord, be it sad or happy or mellow or bright. I kid you not.

These acoustical models are passed on in what is claimed to be a good faith effort to educate the public. But I suspect, many times its done to maker the bearer of such "wisdom" seem wizard-like. Either way, these silly claims fly in the face of even the most elementary teachings of vibrational physics. But that doesn't stop the copy writers in the guitar media. For example, in various trade magazines one advertisement boldly claims, "...scalloped, hand tapered 'parabolic' braces not only give an even balance between bass and treble, but give the clarity of tone ordinary bracing cannot achieve." Yikes! Another ad for a mass-market import boasted that the edge bindings on their guitars are made from "natural Maple--this greatly improves tone and acoustic qualities. The rosewood bridge patch transmits more vibes."

So how should a luthier respond to the question of how guitars work...truthfully?

How about,

"the guitar is essentially a cultural artifact which has evolved in form over the centuries in correspondence with the aesthetic preferences and technological level of its times. Essentially, it is a complex resonating system that transforms the kinetic energy of its strings into acoustic energy in the air surrounding it. Very little is known for sure about how it does that. It offers a method for the user to control just the fundamental frequencies of the harmonic components of the acoustic energy of the generated sound field--that is, the pitch of its notes. The builder determines the production of the remaining frequencies--the ones that determine the quality and character of its notes--only to a very limited extent. However, builders can do so only after persistent trial and error and after developing a refined intuitive sense. But the lion's share of the remaining frequencies in the sound field are fixed by cultural factors such as the guitar's accepted form and by the sum of the intrinsic elasticities of each of its many components."

Although essentially accurate, this description still gives an unsatisfying answer. So a wise skeptic ought rather to view the guitar-maker's work more like a painting or sculpture than as an electronic sound device without batteries. That would be closer to the mark.

Quarter sawn wood vs. rift-sawn vs. vertical grain wood

The adjective "quarter sawn" is popularly used to describe boards that display its annular rings at 90 degrees to its widest face. Much goodness flows from this vertical grain orientation, particularly in ways that are important to luthiers: stability, stiffness, structural efficiency and on and on. However, in truth, there is actually very little "quarter sawn" wood which actually has vertical grain! So if you go to a lumberyard looking for "quarter-sawn" wood, expecting to find vertical grain boards--expect to be disappointed.

(image credits: http://www.wisegeek.com/what-is-quartersawn-wood.htm)

The "quarter sawing" strategy is so-called because the log is cut into quarters and then the quarters are all sawed at a 45-degree angle yielding...very little actually vertical grain lumber!!

That's because the purpose of quarter-sawing lumber is not to extract the greatest yield of vertical grain boards. Not at all. The purpose is to maximize the yield of planks with straight-line figure on their wide faces.

Plainsawing yields the greatest yield of lumber, period. It also yields the widest boards. But it produces very few straight-grain-figure boards and very few vertical grain boards. It produces the greatest amount of wavy-grain-figure or "cathedral" figured boards.

Quartersawing yields more waste that plainsawing. It yields more vertical grain boards than plainsawing, but narrower boards. But all the boards it produces are straight-grain-figure boards.

Now look at the rift-sawing diagram. It would appear to yield 100% vertical-grain boards, but with the greatest amount of waste of all. Indeed some sawyers have computerized equipment that rotate the log to maximize vertical-grain boards, leaving much of it however, on the floor as waste. Technically and correctly, that is called rift sawing.

But this is weird: there is widespread confusion as to what rift-sawing actually means. Commonly, "riftsawn" boards are generally considered to be boards...with the annular rigs oriented 30 to 60-degrees--essentially, most anything between flat and vertical. So that is the term of art, although the popular term is technically incorrect.

So much confusion. What to do? Easy. Stop using the wrong and confusing term"quartersawn". Don't specify "quartersawn" when you ask for luthier timbers: specify "vertical grain".

PS. You all know how particular I am about soundboards. I don't go to lumberyards looking for vertical grain spruce, no matter how "vertical" it seems. "Vertical grain" spruce boards are an inferior source of soundboards for luthiers. If you are a follower of the school from whence I came, you only get your soundboards from suppliers who process spruce specifically for stringed instruments--that is, they don't saw planks at all. They buck the logs at predetermined lengths, use wedges to split them apart into blocks and then saw the soundboards off the split faces. Calling the product of this process "quarter-sawn" soundboards is non-sensical. Calling them, say, "split" soundboards is rather more accurate.

Where the rubber hits the road

I am in the process of finishing a OO 12 fret steel string. When I adjusted the neck angle by adjusting the heel/guitar body joint I ended up with the correct angle per your book page 304 but a gap between the end of the fingerboard and the sound board of 0.060 - 0.080". I suspect this is not uncommon but I am not sure of the best way to deal with this. Just clamp the finger board to the soundboard when gluing the neck in place or shimming the fingerboard extension with an ebony wedge?

This is precisely where the rubber hits the road, vis a vis your building chops. It should all come together: your bridge height and scale length; your fingerboard thickness, how upright your headblock was when you glued your back on, and if your upper transversal face brace had sufficient proper arch. If all those are working precisely and in concert, your fingerboard end will just come down and sit on your soundboard nicely when your neck angle is cut appropriately to your bridge.

The gap you describe is really the total amount of slop that accumulated in all of the above.

If you put a wedge under the fingerboard end, it would look screwy. And that would contravene the Prime Directive: It Can't Look Screwy. On the other hand, you could just glue the fingerboard end down, the most expedient and simple solution. No one will notice, no harm, no foul. It won't look screwy.

But if you try to play beyond your 14th fret, you would probably find it impossible. On a regular guitar, you could say, well, it'll be okay as long as no one plays beyond the 14th fret. But believe me, someone is going to try to play past the 14th fret sooner or later, and then the luthier Gods will punish you.

So what's the solution with the immediate problem at hand? Well if you're lucky, there's the following fix: reset the neck angle for a thinner bridge. That will bring your fingerboard-end down. Were you planning on a 3/8" thick bridge? Well, you're in luck. 3/8" bridges are dogs. 5/16" thick bridges usually work and sound better for anything below Dreadnaught, and even on a Dreadnaught they're better most of the time. Resetting your neck back up is going to move your nut closer to the body, but you can just make up for that when you set your bridge for glueing.

Did you already set the neck angle for a 5/16" bridge. Oh well, that invisible fix is not available. Sorry. You may have to resign yourself with the expedient recourse of just glueing your fingerboard end down to the soundhole.

Next time: make sure your headblock is not allowed to float when you glue the back on. It's real easy to have it accidentally rotate a tiny bit when you clamp the back over it. So make sure it is immobilized 100% when you glue the back on.

If it was immobilized, then the chances are that for your scale, you had insufficient arch in your upper transversal face brace. Make note for the next time to add extra arch.

Also make sure your workboard is flat and rigid if it is cantilevered off the edge of the table. That will throw a chunk of randomness into the equation.

Ed.: The fellow reset his neck for a 5/16" bridge and solved his problem!

More thoughts on wood-specie choice

I'm repeatedly reminded by my experience and research that the choice of wood species plays a rather small effect on the the quality of tone of the guitar made with it.

Excuse me while I duck.

This is an extremely controversial statement in some quarters! I've had to avoid some rhetorical stones thrown at me from makers persuaded to discriminate between a far more narrow list of traditional choices than I.

Regardless, my own perception is that you'd have to posses the ear equal to a spectrographic apparatus to unmistakably discern between a rosewood and a mahogany guitar, let alone between a brazilian rosewood and a thai rosewood guitar. The myth that certain woods are "nobler" than others has been gladly perpetuated by the trade, and as you would guess, the "better-sounding" woods tend to gravitate towards the top of the cost and rarity scale. But I've found over and again, that cost and rarity of the tone woods does not a great guitar insure.

Some recent evidence: I've recently discovered Michigan Sycamore. A student sent me a few sets from a tree that fell in his back yard. Several guitars I subsequently made with that wood rank up with the best-sounding guitars I've ever made. So much for cost and rarity! And the color and figure is as exotic and visually inspiring as the finest Brazilian!

Some older evidence: flamenco guitars. Spanish guitarmakers built Brazilian rosewood guitars for their professional trade, mahogany and walnut guitars for their student trade--and cypress guitars for their holes-in-the-shoe-soles trade. Time was, you could throw a stick in any direction in Spain and hit a cypress tree. The Spanish Roma were the dispossessed population and cypress was literally the cheapest building material you could obtain. The two were joined in flamenco guitars and the rest is history.

Cypress is a conifer--a softwood--a light, foamy-textured gymnosperm, like spruce. Rosewood, of course, is an angiosperm--a dense, glassy hardwood. Totally different fiber and vessel orientation. Nothing more contrasting in density, tambour, texture--you name it--than cypress. Rosewood had to be brought on galleons from Brazil, swapped for barrels of Port wine from Portugal, then sold in Spain as imported lumber or as furniture that was later deconstructed by luthiers to make high-end guitars with. Cypress was sawn from trees in the guitar maker's backyard or cousin's field, where for centuries, long lines of cypress trees divided fields up and served as windbreaks.

Clearly the choice of woods for the fabled flamenco guitars was not made to please guitar "connoisseurs"--it was made to satisfy the pocketbooks of the low-income populace. Yet for at least two centuries, the Spanish Roma created legends of musical history with these knotty, figure-less, "expedient" woods.

I look upon flamenco guitars as guitars with soundboxes made entirely of soundboard material. Is it thus an instrument lesser in grandeur of tone than their rosewood cousins? Is their tone dimmer? Is their musical status inferior? If you believe that, you must listen to a flamenco guitar some day.

So this guitarmakers advice would be to cast away historic prejudices in this regard. Widen your horizons as well as your experience. Go forth and save the rain forests. Check your own back yard. It's safe.

Are larger guitars necessarily louder?

I have not found any real-life evidence to support the popular assertion, "larger guitars are louder guitars." Larger guitars seem simply to have an expanded bass range, usually at the expense of its treble response. My acoustician-mentor Tim White maintained that smaller guitars express their acoustic power in the voice range, to which the ears are more sensitively tuned. That very well may explain why many well-made small guitars can seem to be extraordinarily loud. I can demonstrate that effect with several sub-0 size (also known as parlor or "Ditson") guitars I've made in my shop with students. These 13-14-inch guitars are becoming very popular nowadays, ever since, seemingly, Sting appeared on YouTube with his "baby Ditson". They are ever bit as loud and satisfying to play as any good, large guitar--perhaps even a shade louder. I find the trick is to keep the string scale the same length as you would on a larger guitar. The old parlor guitars tended to sound weak and wimpy, I feel, because their small size was always paired with sub-sized string scales. Pair up a parlor-sized soundbox with a Dreadnaught scale, and you've got yourself a potential small cannon--I've found, and repeatedly.

My soundbox goes dead right after routing for bindings

The book you wrote with Mr. Natelson is an invaluable source of informations and suggestions, as well as your website and blog. Let me say that, besides the strictly technical guitarmaking teaching, I do appreciate your radical intellectual integrity, refusing any kind of shortcut in the making method and in particular in the "skills building" process. Yes I know, this way everyting is a bit harder, and sometimes discouraging... well, for these and other reasons: thank you. ok, ok... let's get in topic...

After routing the binding ledges (7 x 2 mm) I noticed the tone of the soundbox had dramatically changed. this seems reasonable to me, since the routing process removes material at the nodal point of the oscillation, allowing a larger vibration (is it right?). after binding and purfling installation the intial tone was almost recovered, however with substantial changes. so the question is: do you think that the binding choice (material, dimensions) and installation can affect in a relevant manner the final tone of the instrument? If not, can you imagine I did something wrong in my binding installation process?

I honestly don't know for certain. My guess is that since routing the binding usually reveals a number of gaps or holes at the corners that permit air into and out of the soundbox, usually at the spots where the transversal top and back braces meet with the sides (and especially when individual tentellones are used), this creates a lot of air leaks around the rims. The principal of an ordinary resonator requires a single point of escape for the air which is trapped inside the soundbox, and if you pierce a resonator of any sort with countless small openings, all the acoustic pressure gets dissipated instead of focused. Thus--I theorize--the soundbox goes dead when you tap it after routing the perimeters off. A resonator shot full of holes is no longer a proper resonator.

Apparently, binding the guitar subsequently plugs all the small gaps and openings around the rim, and the guitar now can clearly resonate all the frequencies that are are excited when you tap it. I don't wish to speculate as to what the ultimate effect is on the finished guitar's tone. However, it's fair to say that the soundboard has changed in a fundamental way from that of a clamped plate to that of a hinged plate after it has been bound and it is thus freed to vibrate at a considerably lower frequency and greater amplitude than it could before the binding mortises were routed. I imagine that's why the soundbox sounds louder, clearer and deeper-pitched when you tap it after it is bound. No doubt scraping the bindings reduces the thickness somewhat also around the rim, freeing even further the lower-frequency response of the entire soundbox.

Disclaimer: I have no proof of any of this nor, I'm sure, has anyone else. I've only described my reflections on the subject. I can already hear the sounds of skeptics claiming that I'm all wet because guitars with multiple soundholes seem to resonate just fine. Okay, fair enough: I would hasten to ask these folks what happens when you route the edges of these multiple-soundhole guitars, does the same deadening drop in resonance occur? Their response would be revelatory: it would enlighten us as to the differences between the resonance of a given soundbox with one full-size soundhole, one with several smaller soundholes, one with a second sizable soundhole cut out of the ribs (a feature gaining popularity nowadays)---and a series of many smaller air leaks around and just beneath the perimeter of the top and back plates--as what happens after you rout for bindings. And the results of this inquiry...alas, will inevitably lead to even more questions....