Calculation of 1/f Fluctuation from Sound Signal and Comfort Evaluation

• Published in: Applied sciences Vol. 12; no. 19; p. 9425
• Main Authors: Kato, Taro, Kitamura, Takuya, Maehara, Fumiya, Uchino, Daigo, Ogawa, Kazuki, Ikeda, Keigo, Endo, Ayato, Kato, Hideaki, Narita, Takayoshi, Furui, Mitsuaki
• Format: Journal Article
• Language: English
• Published: MDPI AG 01.10.2022
• Subjects: 1/f fluctuation; comfortability; numerical analysis; sound signal; subjective evaluation
• ISSN: 2076-3417; 2076-3417
• DOI: 10.3390/app12199425

Providing a comfortable sound for users is an important factor for high-value products. Therefore, many studies have investigated pleasant sound levels for developing and manufacturing new products. Notably, sounds containing 1/f fluctuations provide a relaxing effect in humans. There are many studies on the influence of sound signals, including 1/f fluctuations; however, the verification of fluctuations, including sound signals, has not been performed. In this study on fluctuation, the discrete Fourier transform was used to directly calculate the time of the sound signal. We evaluated the duration of music and the 1/f fluctuation via the discrete Fourier transform using the time history of the music data. Furthermore, we investigated the relaxation effect of music containing a 1/f fluctuation. We determined a person’s comfort according to the difference in the calculated fluctuation coefficient by subjectively evaluating the comfort felt by people when listening to music with two different fluctuation coefficients, and we examined the improvement in the fluctuation coefficient and human comfort.