The relationship between the fluctuations of harmonics and the subjective quality of flute tone.

Abstract

We studied the relationship between amplitude and frequency fluctuations of harmonics and the perceived quality of flute tones with vibrato. To investigate the effects of minute and irregular fluctuations on timbre, a real flute tone and synthesized flute tones whose relative amplitude levels of harmonics and extent of vibrato were equal to those of the real tone, were used for the subjective experiments. Listener’s preference for flute tones was found to be affected by the degree of intensification or attenuation of the frequency and amplitude fluctuations above 13 Hz. Also, we investigated the physical properties of the fluctuations that affect perceived quality of flute tones, by synthesizing fluctuation waves of harmonics. The results of evaluation by test subjects show that there was no perceived difference in quality between the original tone and synthesized tones with fluctuations that were synthesized by randomization of the phase spectra of the original fluctuations. In contrast, synthesized tones with fluctuations that were synthesized from filtered noise were perceived to be significantly inferior to the original tone. These results suggest that spectral variation of fluctuation waves which is at higher frequency and lower amplitude than spectral variation of vibrato influences perceived quality.