Investigation of a new evaluation method (Octave factor) for guitar tones using FFT analysis

In this paper, the difference between the tone of a high-quality handmade guitar and that of a mass-produced guitar is quantitatively analyzed by using FFT (Fast Fourier Transform) analysis. The sound of each guitar string contains different frequencies. In this time, the sound contained in the open string of the guitar is first decomposed into the fundamental sound, the consonant interval that harmonizes with the fundamental sound (mainly included lower order frequencies), and the dissonant interval that does not harmonize with the fundamental sound (mainly included at higher-order frequencies) by using the 12 equal temperament. In this study, new scheme which defines an octave factor to estimate the content rate of the octave sound is proposed and the sound of the guitar was evaluated using the scheme.