Abstract

Generally, classical guitars have a wooden top and fan bracing as their basic structure, which allows for rich tonal expression, but structurally limits the volume they can produce. Carbon fiber has a higher specific strength compared to wood, thus reducing the mass required to withstand string tension. Therefore, this paper developed a guitar with a new structural that utilizes carbon fiber for the top and lattice bracing. The carbon lattice structure aims to improve vibration efficiency and increase sound volume. Carbon lattice guitar this paper made has successfully reduced the weight more than 0.1 kg lighter than the standard guitar used in this paper. As a result, measurements with an oscilloscope confirmed that the carbon lattice guitar produces a louder sound than a standard guitar on all strings. Furthermore, analysis of the overtone spectrum using FFT analysis indicated the increasing of 2nd overtone, which has an octave relationship to the fundamental tone and is particularly highly harmonious. Furthermore, an improvement in the consonant interval factor, an indicator of tonal harmony, was also confirmed. These results suggest that when designing a classical guitar, in addition to the top material, consider the structure and material of the bracing can adjust the volume and tone. The findings obtained in this paper are expected to contribute to the optimization of the acoustic characteristics of classical guitars by serving one indicator for designing guitars using new materials and new structure.

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