数値計算を用いた音像の距離感に関連する物理パラメータの検討

摘要

Recent 3D technologies allow viewers to perceive the depth disparity of visual objects and, thus, experience more realistic visual information. As for 3D auditory display, however, it has been less convincing for conventional loudspeaker layouts to manipulate perceived auditory depth. Previously, we have proposed a new method that utilizes a prototype electrostatic loudspeaker located above the listening position, which generated auditory imageries similar to headphone-displayed ones. Using this phenomenon and amplitude-based panning, we were able to move auditory imageries along the line connecting the front loudspeaker and the listening position. In addition, we investigated physical factors that were idiosyncratic in the electrostatic loudspeaker reproduction and that caused listener to perceive near auditory imageries, and the variance of group delay was a physical quantity that was associated with loudspeaker-listener distance. In this paper, we analyzed the physical parameter in depth using numerical simulation of loudspeaker-to-ear response, and compares it with the previous measurement. The simulation result shows that plane waves produce smaller variance of group delay in mia-low frequency band and the quantity is less influenced by various reflections compared to spherical waves.%3次元映像は，画面の奥行き感を制御することで立体感を与えている。映像の立体感に合わせて音像の奥行き感を制御できれば，より高い臨場感を視聴者に与えることができる。著者らは，平面波スピーカを受聴者の上方に設置することにより，受聴者の頭部近傍に音像を知覚させられることを利用した音像の距離感制御手法を提案した。さらに,測定結果からこの知覚現象に群遅延の分散が関連している可能性を示唆した。本報告では数値シミュレーションにより,測定結果と同様の結果が得られるかどうか検証した。