被験者の聴感度特性と5．1ch方式による再生音の臨場感の関係

摘要

A 5.1-channel surround system has been popularly used as a sound reproduction system. This paper clarifies how much the perceptual "reality" of the reproduced sound differs among listeners and how the signal bandwidth affects the "reality" of the sound. First, hearing thresholds from 125 Hz to 18 kHz are measured for listeners ranging in age from 19 to 52. As generally known, ability to hear high frequencies degrades among aged listeners. Second, listeners in different age-range are compared with respect to the "reality" of the reproduced original sound and low-pass or high-pass filtered sounds; the original sound signal is extracted from one scene of a cinema. Younger listener's responses was that the narrower the bandwidth the less the "reality", whereas aged listeners hardly distinguish differences among original sounds and low-pass filtered (fc = 8, 16 kHz) sounds. Results are similar when surround headphones are used, whereas filtering effects are small when sounds are reproduced by a binaural system using head-related transfer function.%5．1ch方式の個人個人の聴力による聴こえ方の違いや、必要な周波数帯域を明らかにすることを目的として、主観評価実験により通常の5．1chの音響信号とその音響信号を帯域制限したものを比較することで、高・低周波成分の臨場感に対する寄与度を明らかにした。次に、被験者間による結果の違いを比較することで、聴感度特性と5．1ch方式による再生音の臨場感の関係を明らかにした。また、バイノーラル方式とサラウンドヘッドフオンでも比較評価を行い、再生方式による高・低周波成分の臨場感に対する寄与度の差を明らかにした。