This study investigates a method for reproducing the near-ear sound field around the pinna using a compact half-circle loudspeaker array placed on the ear. The desired sound field is calculated by modeling the head as a rigid sphere, and the driving signals for the loudspeakers are obtained using the pressure matching method. While this approach enables directional localization, it has limitations in presenting auditory distance due to the absence of reflected sound components. To address this issue, we simulate reflected sound fields in a horizontal plane based on an image source method within a square room. However, the reproduction of higher-order reflections increases computational cost, which significantly impacts real-time applications such as interactive systems with head tracking. In this study, we focus on the relationship between the order of reflection and perceived auditory distance, aiming to identify the minimum reflection order required for accurate distance reproduction. Subjective evaluation results using the proposed system indicate that increasing the reflection order improves the perceived distance toward the intended target. Although the improvement in perceived distance plateaued at higher reflection orders, it was sufficient to allow listeners to distinguish differences in virtual source distance. Work supported by NTT, Inc.
Sakumoto et al. (Wed,) studied this question.