High-resolution music with inaudible high-frequency components produces a lagged effect on human electroencephalographic activities

Abstract

High-quality digital sound sources with inaudible high-frequency components (above 20 kHz) have become available because of recent advances in information technology. Listening to such sounds has been shown to increase the α-band power of an electroencephalogram (EEG). The present study scrutinized the time course of this effect by recording EEG along with autonomic measures (skin conductance level and heart rate) and facial electromyograms (corrugator supercilii and zygomaticus major). Twenty university students (19-24 years old) listened to two types of a 200-s musical excerpt (J. S. Bach's French Suite No. 5) with or without inaudible high-frequency components using a double-blind method. They were asked to rate the sound quality and to judge which excerpt contained high-frequency components. High-α EEG power (10.5-13 Hz) was larger for the excerpt with high-frequency components than for the excerpt without them. This effect was statistically significant only in the last quarter of the period (150-200 s). Participants were not able to distinguish between the excerpts, which did not produce any discernible differences in subjective, autonomic, and facial muscle measures. This study shows that inaudible high-frequency components have an impact on human brain activity without conscious awareness. Unlike a standard test for sound quality, at least 150 s of exposure is required to examine this effect in future research.

A Meta-Analysis of High Resolution Audio Perceptual Evaluation

“…However, the extensive research into brain response to high resolution content suggests that exposure to high frequency content may evoke a response that is both lagged and persistent for tens of seconds, e.g., [22,48]. This implies that effective testing of high resolution audio discrimination should use much longer samples and intervals than the ITU recommendation implies.…”

Inaudible components of the human infant cry influence haemodynamic responses in the breast region of mothers

“…In the present study, every participant was exposed to both natural cry sounds with intact ultrasonic components and scrambled cry sounds whose ultrasonic components were destroyed in its frequency structure. Considering the previous studies indicating the unconscious effect of inaudible components on behaviour [45,46] and neural activation [21,22,31], the neural system may have detected subtle "unnaturalness" in the scrambled cries due to a contrast effect induced by the presentation of high-fidelity natural cry sounds. This design might have attenuated physiological responses to scrambled cries in the present study.…”

High-Resolution Audio with Inaudible High-Frequency Components Induces a Relaxed Attentional State without Conscious Awareness

“…It has been shown that EEG alpha-band (8–13 Hz) frequency power is greater for high-resolution music with high-frequency components than for the same sound sources without them ( Oohashi et al, 2000 , 2006 ; Yagi et al, 2003a ). The effect appears more clearly in a higher part of the conventional alpha-band frequency of 8–13 Hz (10.5–13 Hz: Kuribayashi et al, 2014 ; 11–13 Hz: Ito et al, 2016 ). Ito et al (2016) reported that low beta-band (14–20 Hz) EEG power also showed the same tendency to increase as high alpha-band EEG power.…”

“…In contrast to this conventional digital recording process in which inaudible high-frequency components are cut off, high-resolution music that retains such components has been repeatedly shown to affect human electroencephalographic (EEG) activity ( Oohashi et al, 2000 , 2006 ; Yagi et al, 2003a ; Fukushima et al, 2014 ; Kuribayashi et al, 2014 ; Ito et al, 2016 ). This effect is often called “hypersonic” effect.…”

“…Some studies have shown that full-range audio is rated as better sound quality (e.g., a softer tone, more comfortable to the ears) than high-cut audio ( Oohashi et al, 2000 ; Yagi et al, 2003a ). Another study has shown that participants are not able to distinguish between the two types of digital audio, with no significant differences found for subjective ratings of sound qualities ( Kuribayashi et al, 2014 ). The feasibility of discrimination seems to depend on the kinds of audio sources and individuals ( Nishiguchi et al, 2009 ).…”