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Compression-molded, 100% carbon-fiber laminated guitar soundboard


The Cumpiano guitar illustrated on the right is entirely made with  traditional materials -- all except for its black sound board, which is made from  compression- molded graphite carbon-fiber-laminate material.

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From time immemorial, softwoods such as pine, spruce, and cedar have been selected by instrument-makers for the sound boards of their stringed instruments. The tradition continues to this day. Indeed, modern makers select these traditional materials for the same reasons as did their forebears: they are efficient, (i.e. very stiff  relative to their weight); they can bear considerable loads (such as that imposed by string tension) even after they are sawn into thin sheets. Optimally, sound boards are thin in order to minimize mass, mass which can dampen the vibrations and reduce the sustaining quality of the sound.

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"like polished marble tweed..." I've found that graphite loves lacquer. Here we see it on a Purpleheart nylon cutaway.

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Below is another interesting carbon fiber laminate project, this time a severe "thinline" (under 2" high) cutaway guitar prototype. Not even finished yet. The result is a suprisingly satisfying acoustic guitar sound with far more low end performance than you would find in a commercial, thinline acoustic-electric guitar in a music store. And surprisingly loud and full-bodied, like a good "normal" guitar. The frequency range, you will find in this .MP3 sound sample (played by my admired friend, the guitarist Andrew Lawrence during an informal try-out) is colored by it's lack of braces, with a sound that is reminiscent of other braceless stringed instruments: a banjo  or a steel guitar. It sounds rather like a Selmer Macaferri jazz guitar when pumped with a pick, but sweetens up when played fingerstyle, as the sound sample demonstrates...


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But thin sheets of softwoods crack easily when exposed to ordinary climatic changes. They also "creep." Creep is a technical term that describes the plastic deformation of a material after it has been under stress for a long time. After years of use, many lightly-constructed guitar tops display rippling, sinking, and bulging -- deformations that remain "set" even after the string tension is released.

A logical alternative to spruce for sound boards are modern fiber-composite materials. They, too, are strong and light. They are also more uniform, an advantage that simplifies production processes. Music instrument soundboards can be fashioned from this multi-laminate fiber-composite material because it closely mimics the an-isotropic (non-uniform) stiffness characteristics of spruce.

The material is a modern alternative to the traditional softwood sound boards which can be used on all kinds of plucked stringed instruments.  The material as an analog to Spruce wood--which, by the way, is also made up of carbon-based fiber. The trick was to design the lay-up of the sheets to mimic the peculiarities of the natural material, so that its sound would be similar.

The material is composed of many laminations of resin-impregnated carbon fiber "skins" which are laid up in a special way. The lay-up is then heat-pressed to a 1/16 to 1/32-inch thickness. The process yields an enormously strong, stable and light material that will never creep or crack. The material also displays superior acoustic characteristics: when held up and rapped with the knuckles: the material rings like a bell! The material's outer face displays a beautiful,   woven layer of carbon fiber a under polished lacquer" Indeed, a small number of other instrument manufacturers have developed their own composite soundboards, notably the Ovation and Decker/ Windsong guitar companies. Their own patented processes, however, are significantly different from the layups I'm using, and result in sound boards that are not as acoustically efficient or as attractive.

I'm currently still in the R&D phase of this project, and am not currently offering these models for general sale (although I have sold several prototypes in the past). I hope to resume offering these unusual instruments again in the near future.