Surgeon by day, luthier by night- Kevin Muiderman makes artist-quality acoustic and classical guitars using the composite or "sandwich" top technique. This precision technology employs the same honeycomb carbon-fiber material used in Stealth aircraft and produces a feather-light instrument with excellent projection and superior strength. An impressive guitarist himself, Dr. Muiderman has recorded an instrumental CD and often sponsors acoustic guitar concerts in his idyllic woodland home.

I have been building guitars for only 10 years or so but very early in my career, frustrations with control and consistency of sound led me to explore non-traditional bracing patterns and composite materials in the construction of steel-string and classical guitars. The exploration has been thrilling, and the results have been sonically and emotionally rewarding.

I love acoustic guitar music more than any other sort of musical expression. I don't know exactly why, but I accept that it is so. I have been playing classical and fingerstyle guitar for about 35 years and recently recorded an album. I also love working with my hands. I am a surgeon by trade and have always enjoyed building furniture, making ceramic, metal and wood sculpture, and drawing.

In an effort to combine two great passions, it has always been my dream to create fine acoustic guitars. But traditional schooling always took precedent. However, after finishing my medical residency, it was a joy to finally have the opportunity to learn to build acoustic guitars. I traveled to Leeds Guitarmakers' School in Northampton, MA to study steel-string guitar craft with master builder and teacher, Ivon Schmukler. After several intensive tutorials with Ivon, I felt I had learned what I needed to start out on my own.

Kevin explains the rational of building composite tops with lightweight carbon fiber materials covered with thin "skins "of wood.

My path toward unconventional methods of construction began shortly after completing my first guitar in my home shop. The guitar sounded fine. Based on a basic Martin OM design, it wasn't surprising that it had some Martin character. But it also produced a little extra midrange boost that gave it a color all its own. As I continued to play this mahogany guitar with a Sitka spruce top and compare it to other guitars, I had a pivotal moment of disillusionment.

My realization was two-fold. The first conundrum was an issue of control. None of the guitar experts I queried could help me understand why my guitar had a different tone than a similar Martin, although it was by all accounts an ounce-for-ounce, 64th-for-64th-inch copy of a Martin OM. Was it the character of the wood, the angles of the tone bars, the weight of the bridge, the stiffness of the neck, or the particular scalloping of the braces? All of these explanations were given, and all were reasonable. But none of the answers made it clear which elements actually contributed to the variation in sound. Coming from a science background, I wanted to be able to reproduce the midrange boost I was hearing, or to remove it, or to add or subtract other tonal qualities at will, or to make two guitars that sounded exactly alike. The lack of consensus about what makes a guitar sound like it does left me confused.

Once the braces are glued in place, Kevin inlays a layer of carbon fiber material in each brace for extra strength and rigidity, without adding significant weight. The mandolin at right also has a lightweight composite top.

The second facet of my disenchantment was one of purpose. My dream was to build some of the finest guitars in the world, instruments that would be sought by professional players to make their music and their living. I was sure that with good training and discipline I could rise to some sort of distinction. But I had no idea how many brilliant guitar makers were already pushing the envelope sonically and technically. It was suddenly clear that I had been naïve and that in my lifetime I could never achieve a level of control that would distinguish my instruments from the hundreds of fantastic, traditional, handmade masterpieces built each year.

But I remembered a conversation with one of the teachers of classical guitar construction at the Leeds school, Alan Chapman. Alan stopped by the school one day with a prototype classical guitar he was developing. There was no lacquer or finish of any kind on the instrument, and the top seemed to be bonded at its seams and at the waist with blue masking tape. I recalled how when he stroked the strings of this homely, inelegant instrument, the notes projected with unique clarity and balance to the back of the shop and could be discerned without great effort, even over the noise of the dust collector. At the time we talked only briefly about his methods of experimentation and his own desire to understand and control tone, dynamics and consistency.

Works in progress on the Muiderman shop wall.

So I returned to the Leeds Guitarmaker's School to study with Alan. He was intrigued with the work of the famous Australian classical guitar maker, Greg Smallman, who created an ultra-lightweight, carbon composite lattice bracing system. To understand more about the principles underlying ultra-lightweight tops, Alan devised test instruments that could be easily disassembled and reassembled to work through ideas prior to production. Using these test guitars, he altered only one element at a time and listened for the change in sound that might result from the alteration. By changing the dimension, weight, or wood type of any element incrementally, he discovered not only which elements were critical to a particular tonal quality, but how to control that tonal quality. His results were astounding.

With new determination I returned home to extrapolate the principles Alan used in his classical guitars to the tensions and dimensions of steel-string guitars. I immediately built two steel-string "test" bodies with bolt-on necks. The bolt-on neck allowed me to experiment with neck materials and dimensions and, more importantly, easily remove the test tops. Because the tops were left unbound, with a little heat applied to the Tightbond glue, they could easily be cut off with a knife blade inserted between the top and the kerfing. This way, tops could be altered and replaced and tested several times in a single day. Bridges and back bracing were similarly removed, altered and replaced at will.

Kevin stringently analyses the sonic effect of each new design innovation, recording minute variations in weight, materials or dimensions in his shop journal. Here, he plays his "test guitar" which may undergo several major alterations in a single day.

My first tops looked much like the Smallman-style tops Alan was experimenting with at the time. They were braced with a lattice consisting of 18 interlocking, lap-jointed balsa wood diagonals overlaid with graphite to add just enough rigidity. My first attempts were not structurally sound and provided very little sustain; although they did not sound very wooden or pretty, they were extraordinarily loud. Using my test guitar, I gleaned a great deal of information about the limits of lattice systems and the demands of steel strings.

Over the next several years I tried out different bracing patterns, materials, and dimensions and took great care to record each element to the thousandth of an inch and tenth of a gram. At some point during the process of refining a given element--for instance top thickness or bridge weight--the sound of the guitar would pass through a point of optimum clarity. Dimensions were carefully recorded and the incremental addition or subtraction of material continued until the sound lost its focus. Each key element--the top material, top thickness, bracing pattern, bracing material, bridge material, bridge dimension, back bracing, neck material etc.,--was tested in turn to understand its properties, limits and its contributions to structure and tone.

Track lighting brightens the well-organized Muiderman shop. A precision sander in an adjoining room enables Kevin to create the ultra thin cedar or spruce skins that comprise the "bread" of his sandwich tops.

As the lattice, carbon composite bracing of the tops became lighter and stronger, it was clear that the majority of the mass of a top as well as its unpredictability came from the wood of the top itself. It seemed logical, therefore, to pursue the possibility of using lighter, stronger, more controllable materials for the top. So about 4 years ago I looked again to some of the great classical guitar design innovators like Humphrey and Dick and to Cumpiano who developed graphite tops for steel-string guitars. It seemed clear that the use of graphite and Kevlar by these makers resulted in great-sounding tops with strength equivalent to traditional wood tops- but with far less mass.

Through countless experiments with alternate top materials, my greatest success came from using a Kevlar honeycomb material between two "skins" of traditional top wood. This "sandwich" resulted in an extremely strong but essentially hollow, light top which retained a controllable, extremely pleasant, "wooden" tone. The ultra-light top in conjunction with the ultra-light, lattice, composite bracing system provided an extraordinary dynamic range that to this day I've been unable to achieve with traditional methods.

Muiderman's abstract rosette designs are each one of a kind.

Throughout my exploration of unconventional steel-string guitar design, generous "test pilots" have provided invaluable input. Once I had gained a desirable tonal quality or had achieved some significant increase in dynamic range, I would locate the best guitar player I could find to take the new design through its paces. By listening not only to players' comments but also to how the guitar responded to their particular playing styles, I was able to correlate recent design changes with the sound coming from the guitar. About four years into my experimentation I was fortunate to enlist the expertise of acoustic guitar virtuoso, Martin Simpson. He remains an invaluable resource in the advance of my steel-string designs.

Finally, my evolution in design has taken me full-circle, back to classical guitars. Smallman revolutionized classical guitar construction. I learned what I could from his design and expanded on his ideas and the innovations of others to create new steel string designs. Recently, I have taken the principles I've gathered from my steel-string work and applied them to new classical guitar designs. As with my steel-strings, I am currently combining a "sandwich" top with composite, lattice bracing in my classicals and once again, the results are satisfying.

Simple, tasteful design elements and a high level of craftsmanship are the hallmarks of Muiderman's instruments.

Over these 10 short years, I have discovered several broad principles that continue to influence the progress of my designs: 1) If you can make something lighter but just as strong, you might be on the right track. 2) A guitar is like a spreadsheet. If you change one element- i.e., type of wood, brace dimensions, weight of anything, dimensions of the body --all other elements have to be brought into line, or impedance match with that change to achieve a balanced tone. 3) As long as you're testing, you're not building product, so there has to be some sort of balance between R&D and production. Hopefully there are some plateaus along the way that allow you to crank out a few marketable instruments to keep you going.

I will never be able to match the work of the great traditional builders, but my joy comes from working with alternative bracing systems and composite materials to increase dynamic range and gain control over tone. It's an exciting, evolutionary process; the more I discover, the more questions I have, and the more their logical extensions pull me toward new experiments and onward to new designs. I am no longer making the instruments I was making three years ago because the new guitars sound bigger, more even and prettier than what I was making then. And I am quite sure that two years from now, I won't be building the same guitar that I am making today.

Consequently, I will never enjoy the broad marketability of the best traditional builders. But because of the distinctive clarity of sound and dynamic range I have achieved only 10 years into my process, I've been privileged to build custom instruments for some of my favorite players and some of the best guitarists of our time. Most of all, it remains great fun. And I wouldn't have it any other way.