By Teja Gerken
Wood has been the primary material used to build virtually all stringed instruments for as long as stringed instruments have been around. Although alternatives have occasionally been used (let's not overlook those unfortunate armadillos who met their demise as the backs of charangos), the guitar market is one of the few places in modern life where 50-year-old technology is considered to be the most desirable. Although Mario Maccaferri enjoyed considerable success with his plastic ukuleles and violins in the '50s, his line of guitars made of the same material--no matter how cool and collectible they may seem today--failed miserably. Other companies have continually tried their hands at incorporating composite--and particularly synthetic--materials in guitar construction, but to this day, Kaman Music's Ovation is the only guitar of this type to withstand the test of time and be accepted widely by players.
Today, however, alternative materials are becoming more and more commonplace in musical instruments. As the supply of high-quality traditional tonewoods continues to shrink, guitar manufacturers and individual luthiers have begun to pay attention to how other industries, such as the tennis racket and aerospace industries, use composite materials--often a combination of carbon fibers and epoxy resins. Guitar makers are also researching the use of nonrainforest woods that have been harvested in an environmentally conscious way, but the possibility of replacing entire guitar components with composite materials has several manufacturers looking into space-age alternatives, which offer a new set of characteristics and possibilities. Others feel that wood is still the perfect base material for building stringed instruments but find that the combination of wood and composites allows them to come up with design improvements that wouldn't be possible with wood alone.
To find out where these developments are heading, I spoke to some of the people on the composite cutting edge. Steel-string and classical luthier William Cumpiano and small-scale manufacturer Rick Turner both employ composite materials in a number of their instruments. Cumpiano holds a patent for the use of carbon fibers in guitar tops, and Turner has patented the use of similar fibers in guitar necks. John Decker is the founder of RainSong Guitars, whose instruments currently represent the most radical use of carbon fiber guitar construction. Don Johnson is the director of research and development at Ovation and has been a key force in the development of the company's Q model prototype. Ken Parker has pioneered the combination of wood and carbon fiber in his radical Parker Fly guitars, and Tim Teel of the research and development department at the Martin Guitar Co. has had crucial input in the design of the company's groundbreaking DXM model.
As with anything new, there is as much disagreement as agreement when talking about the use of these materials. While there are clear benefits, such as the materials' consistency and imperviousness to humidity, one of the biggest hurdles any nonwooden guitar has to jump is player criticism. If musicians won't approve of an instrument's unusual looks or unexpected tone, the new design is worthless. In the case of Ovation Guitars, the radical appearance and sound introduced some 30 years ago has become their trademark feature. The round-back's punchy, focused acoustic sound helped bring it into the hands of players ranging from folkies like Josh White to jazz fusion stars such as Al Di Meola, whom the company recently honored with a signature model. It's this kind of forward thinking that makes new materials so exciting. While it might be cool to stamp out instruments built of composite materials that sound exactly like prewar Martins, it's even cooler to hear how new technologies can change and improve an instrument's sound and performance.
Rather than relying on carbon fibers as the primary material in the construction of their instruments, several builders are incorporating the material in otherwise wooden instruments. "The composite material is a terrific way to modify wood," says Ken Parker. "Tonally, it's just wonderful, because you can use a piece of wooden material that has a lot of fine attributes but that in itself is not capable of the discipline that you want in a musical instrument." As a result of this philosophy, Parker's revolutionary Fly guitars feature extensive carbon fiber reinforcements. They're solid-body guitars, not acoustic instruments in the traditional sense (although they feature Fishman piezo-pickups for an acoustic-electric sound), but Parker points out that you have to start with excellent acoustic properties to build a superb electric or acoustic-electric instrument. And many of Parker's innovations could be applied to a wide variety of instruments. "Clarity and evenness are very important," Parker says. "My early instruments were not composite materials, but were covered with ebony veneer or another hardwood veneer. With that veneer and a soft wood neck, I was able to create a neck structure that was beautifully disciplined, very clear and even, and capable of producing close voicings without rattling around and doing bizarre, unmusical things." By using carbon fiber and epoxy resin instead of a hardwood laminate, Parker is able to build lighter instruments and to produce them more easily in a factory environment.
Another and perhaps more radical use of composite materials is found in Parker's fingerboards. He began using composites for fingerboards to avoid using endangered woods such as rosewood and ebony, but he quickly found that the new material enabled him to take a completely new approach to installing frets. Foregoing the traditional process of hammering or pressing the wire into precut slots, Parker glues his frets flush to the fingerboard. Because of the precision and stiffness of the Parker neck and fingerboard, the frets need no further treatment--no crowning, no removing of marks left by the comparatively crude installation procedures used by virtually every other guitar manufacturer.
Rick Turner also looks at composites as a way to solve problems, and fingerboards are high on his list. A guitar he displayed at last year's Acoustic Guitar Festival featured a fingerboard made of pacowood, a material that uses layers of dyed birch veneer that have been laminated and impregnated with phenolic resin under high heat and pressure. Turner further strengthened the fingerboard with graphite reinforcement bars running its entire length. "My concept here is that the fingerboard itself becomes a structural element of the neck," Turner explains. "The fingerboard was much stiffer than the shaft of the neck. In fact, I was able to put the fingerboard on two blocks and stand on the center of it." Another structural problem this fingerboard design combats is the neck-to-body joint, which is often compromised when the guitar's top moves under different humidity conditions. "This gives you absolute predictability and stability from the nut to the very last fret," he says. "The guitar body cannot have influence on the neck."
Turner also used graphite in the same guitar in flying struts that support the neck block against inward pressure from the neck. "This allows me to lighten up the bracing of the upper bout of the top to get more tonal complexity," he says. In a less high-tech approach, Turner has also used Formica (yes, the same material found on kitchen counters) as fingerboard material. He was originally attracted to it because of its color possibilities. Turner describes the sound as offering "a little more snap, a little more edge, and a little more sustain," but he also warns of potential problems when it comes to inlaying and refretting Formica.
Following the example of Australian classical luthier Greg Smallman (who occasionally uses graphite-reinforced balsa wood braces), Turner is currently experimenting with the use of composites to stiffen braces. Using the principle of the I-beam, in which two flat lateral struts gain rigidity by being separated with an upright support, he has capped the back braces of an instrument in progress with a thin layer of graphite. "It is unbelievably strong," he claims. "I suspect that when I get the back onto the sides, the back might actually support my weight as well."
William Cumpiano is a builder who dances between making guitars completely out of composite materials and using carbon fibers for reinforcement only. A well-respected luthier with over 30 years of experience, Cumpiano has recently begun offering compression-molded carbon fiberlaminate soundboards as an option on his custom creations. Cumpiano calls the material "a kind of idealized wood. You're really talking about something that is similar to wood in the sense that it is a carbon fiber, just like cellulose [the material that wood is made of] is a carbon fiber, and it's in a matrix of glue. In the case of these laminates, the matrix is epoxy, and in the case of wood, the matrix is lignin." He points out that wood is of course a whole organism of far more complex structure than its modern counterpart. "You really have to select wood to find the qualities that you're looking for," says Cumpiano, "but you can make the plates of carbon fiber more or less like you want them. Also, you can create much greater uniformity and therefore get better results." Although other builders, including RainSong's John Decker, have found it problematic to combine graphite tops with wooden backs and sides, Cumpiano has had no problem. "They work fine," he says. "I think they work so well together because they're essentially very similar."
Today, RainSong is the only commercial guitar manufacturer that makes its guitars entirely out of graphite composites. Inspired by the difficulties of maintaining a wooden instrument in Hawaii's extreme humidity conditions, Decker initially experimented with graphite tops only. "If you're interested in a guitar that is relatively sturdy and impervious to the weather, that's a very difficult approach to take," he says. "A hybrid system is far harder to make work. The two materials [wood and composites] have radically different properties. We had a couple of early prototypes that demonstrated this in spectacular ways, with bonding failing and so on."
Since Decker was in Hawaii, it was a natural move for him to look into the same epoxies used in the surfboard industry when he started out. However, he quickly discovered that this wasn't the way to go. "We had real problems with delamination and the stuff not flowing into all the corners," he explains. As it turned out, industrial material used by the tennis racket and aerospace industries yielded much better results, and because of previous business connections, Decker was able to obtain the materials in the relatively small quantities needed by his company.
The first RainSong guitars were designed by Lorenzo Pimentel (of Albuquerque, New Mexico's Pimentel and Sons) and essentially constructed in a traditional manner, but Decker eventually realized that it would be necessary to design the instrument from the ground up with composites in mind, finally leading to the process he now uses, which is called projection-tuned layering. This method takes advantage of the carbon fiber's physical strength and allows the guitar to be built without bracing, thus greatly reducing the weight of the top. Decker says, "Almost all of our sales are now made on the basis of sound, not on the basis of fragility, weather, or travel restraints." He describes the difference in sound as a subtle distinction, a matter of taste. "It's like the difference between a spruce soundboard and a cedar soundboard," he says.
Compared with RainSong's global use of carbon graphite, Ovation's line of Adamas guitars represents more of a hybrid of available technologies. Wood is still used for the neck and fingerboard and as a major component of the top construction. The Adamas' top is made of two thin layers of carbon fiber sandwiching a birch core. It's another use of the I-beam principle as a way to gain strength. Says Ovation's Don Johnson, "The fibers themselves don't like to stretch and they don't like to be compressed, but they bend OK. If you took just the top or bottom layer of the Adamas top, even in the cured state, you could bend it all over the place. In order to take advantage of carbon fiber's tensile strength, you need to separate those fibers in some way." The result of this layering technique is a top that is extremely thin and strong and is still able to be fine-tuned with various bracing patterns. Although Ovation has experimented with carbon fiber braces, according to Johnson the results have thus far been undesirable, and Ovation continues to use spruce for bracing.
First shown to the public at the winter '98 NAMM show, the Ovation Adamas Q took the carbon concept to the next level. The instrument, which is still in the prototype stage, was made almost entirely out of carbon fiber. Besides the thin layer imbedded in the top, only the fingerboard, bridge, and braces were wood. The Q's clean, symmetrical lines and completely acoustic design as well as its neck-through body construction and amazingly light weight were the result of true innovators at work. In the future, some of these developments will appear in Adamas' regular production models.
On the other side of the conservative-to-radical spectrum lies C.F. Martin and Co., an institution based on tradition. Martin surprised many industry insiders when it introduced the DXM model in 1998. The DXM's body is made almost entirely of a high-pressure laminate material--a wood-fiber derivative that's laminated under extremely high pressure and coated with a mar-resistant surface. The guitar-which lists for $599, making it by far the least expensive instrument mentioned in this article-represents an important step in the ongoing search for alternative materials. Thanks to its photo finish, the instrument appears to be made out of mahogany and spruce (models with pseudoBrazilian rosewood and black finishes have also been introduced), and the traditional mahogany neck and dreadnought shape give it the classic Martin feel. The company was able to bring the price down so low because the high-pressure laminate drastically reduced the amount of time necessary to complete each instrument. "It's already finished when you get ahold of it," says Tim Teel, "so it really cuts down on finishing time. The only thing that gets a light finish is the neck."
Like everyone else who is experimenting with composite materials, Martin found that many aspects of its proven designs didn't work when transferred to the new material. Says Teel, "To get a decent sound from it, we needed to redesign the bracing to the point of actually adding more material to the top, because the high-pressure laminate is only about 50 thousandths of an inch thick, which is much thinner than a standard wood top. It's much more flexible too, so we needed to add more material to the bracing to stiffen it up and give it the sound we were looking for." Teel also found that a modified bridge plate was necessary to acquire the desired sound, resulting in a two-piece design that wouldn't be feasible with a wooden top. A mahogany bridge plate elicited a good bass response and Indian rosewood a good treble response, so Martin decided to use both. "Because of the high-pressure laminate itself, we could do a split bridge plate," Teel explains. "On a joint spruce top, you wouldn't want to do that."
So, why would a musician want to play a guitar made of composite materials? Besides the obvious physical strength and resistance to change under extreme temperature and humidity conditions-which make these instruments excellent partners for the road-everyone involved in their manufacture agreed that the precision and predictability gained by the use of the new materials is one of the biggest benefits. But there are other factors that might sway players to take one of these instruments into more serious consideration. "A friend of mine, a very fine jazz guitar player, called me up after having bought one of our instruments," recalls Parker. "After having played it for a couple of weeks, he said, 'You know, any other guitar that I play, when I get excited and I start getting sweaty, the fingerboard slows down. On your guitar, it speeds up.'"
Cumpiano has found that the guitars he builds with carbon-fiber tops make excellent acoustic-electrics. "We're finding that [under-saddle] pickups just love the graphite," he says. "The sounds that come out have a beautiful clarity and sustain, a very nice confluence of the two. I don't know specifically why that is, but we know that graphite has less dampening effects than wood, and I think more of the signal gets to the pickup, so the pickup can operate at a lower level." Decker agrees, and he believes that another contributing factor is the fact that graphite itself is an electrical conductor. In describing the acoustic sound of his guitars, Decker says, "The main difference is that the trebles are a lot more pronounced. Wood absorbs high frequencies, and if you're doing high harmonics on the high E string, for instance, they tend to come across in the attack but not as much as usable tone. That doesn't happen with a graphite instrument. It's a lot more forgiving."
Indeed, a RainSong WS1000 that I was able to spend some time with displayed an unusually bright and crisp upper range, without being piercing or unbalanced. I was also impressed with the guitar's volume, sustain, and amazingly even response throughout its fingerboard. I had a similar experience playing Ovation's Q prototype. Although very different from the RainSong in feel and sonic character, it possessed many of the same qualities of evenness and precision. To my surprise, both guitars displayed an amazingly organic voice, and the RainSong in particular didn't feel overly stiff, as I thought a graphite neck might. While neither sounded "just like an old Martin," to use a common phrase, they each had an attractive acoustic sound that doesn't need to fear comparison with that of a fine wooden instrument.
A multitude of capable luthiers are now incorporating composite materials into their instruments in ways that open new doors for design. With a healthy dose of experimentation in progress, only time will tell what impact composite materials are going to have on the acoustic guitars of the future.