The effect of listening to high-resolution digital audio on cognitive function

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K18702
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Research Field: Psychology and related fields
• Research Institution: Osaka University
• Principal Investigator: Nittono Hiroshi 大阪大学, 人間科学研究科, 教授 (20304371)
• Project Period (FY): 2017-06-30 – 2020-03-31
• Keywords: 実験系心理学 / 心理生理学 / 聴覚

Outline of Final Research Achievements

High-resolution audio is a generic term for systems that can render beyond standard quality audio such as CD or DVD. This study dealt with how high-resolution audio affects the listener's experience. A series of experiments using the electroencephalogram (EEG) and evoked brain potentials revealed the following three findings. First, listening to audio materials that contained inaudible high-frequency components induced a larger oscillatory power on the EEG than listening to similar materials from which the high-frequency components were removed by digital filtering. Second, filtering out high-frequency components caused a temporal smearing of the sound (i.e., blurring instantaneous sound onsets), but the difference was not registered in the auditory cortex when the sampling rate was not changed. Third, when the sound was converted into a lower sampling rate, the resulting temporal distortion may have affected auditory neural processing from the inner ear level.

Free Research Field

実験心理学

Academic Significance and Societal Importance of the Research Achievements

ハイレゾ音源は情報量が多く，可聴域を超える周波数帯域まで再現できる点がメリットだと言われることがある。しかし，今回の研究から，ハイレゾ音源の効果は，高周波音成分によって生じるのではなく，音の時間的歪みを少なくできるために生じることが示唆された。デジタルオーディオであっても，データを物理的な音に変換して再生するアナログ経路がきわめて重要であり，その部分を改善することが聴取体験の向上につながるといえる。