Development of a carbon-fiber-reinforced composite for guitar soundboards: Investigation of bracing effect by experiment and simulation

A carbon-fiber-reinforced polyurethane foam composite whose physical and acoustic properties closely resemble those of wood for stringed-instrument soundboards was developed. A guitar with such a composite-made soundboard produced an almost identical tone to that produced with a wooden soundboard. The procurement of wood for soundboards, however, has not yet become very difficult. To accelerate the production and use of guitars with composite soundboards, it is necessary to create an attractive guitar that has characteristic and unique tones that cannot be realized on a wooden soundboard, making use of composite characteristics of design freedom. Wooden top boards, soundboards, have bracing that has traditionally and experientially been glued; however, the effects of bracing have never been clarified. In this study, the bracing effect on the frequency response and vibration mode in a guitar top board was investigated using experimentation and simulation. From the results obtained, a composite-made soundboard with no bracing, which produces more harmonics than a wooden one with bracing, was simulated as an example.