楽曲の知覚有無と体表面上の非可聴高周波成分の音圧分布がハイレゾ音源のハイパーソニック・エフェクトに及ぼす影響

抄録

Sound sources with ultrasound components have a positive effect on human beings, known as the hypersonic effect (HSE). To investigate the conditions causing HSE, changes in alpha waves in response to ultrasound were examined under these conditions:(1) almost similar ultrasound level from head to foot, (2) reduced ultrasound level below the neck, (3) Same conditions as (1), but use of noise-canceling headphones and noise masking, (4) increased in (2) such that the mean ultrasound pressure is equal to that of the super tweeter in the (1), (5) decreased sound pressure levels at the head and chest or only at the head, and (6) exposing ultrasound only to those body parts with a large area of the somatosensory cortex. Significant differences in alpha waves were found under conditions (1) and (3);however, no differences were found under conditions (2), (4), and (5). These results indicate that a wide distribution of ultrasound pressure on the body surface is re-quired for HSE to occur. HSE depends on the distribution, even at the same average sound pressure of the ultrasonic components. In addition, HSE improves the behavioral and psychological symptoms of dementia and reduces postprandial blood glucose elevations. The results of this study can be used for several HSE applications. This phenomenon also occurred when people had difficulty listening to music. This suggests that it is also effective for people with hearing loss.