Arrival direction of late sound and listener envelopment in concert auditoria

本研究的目的是探讨迟发声音的到达方向与知觉听者包络之间的关系。在电波暗室中利用三维模拟声场进行了一系列的心理实验。首先，分别考察了来自四个基本方向的迟发能量对感知水平的影响。结果表明，侧向声级与LEV的相关性最高，而来自听者头顶和后方的迟发声音也与LEV有很强的正相关关系。其次，通过实验明确了晚期声的方向性能量分量对LEV的贡献程度。结果表明，不仅横向水平对LEV有显着影响，后方和头顶的迟发声音对LEV也有显着影响。此外，定向晚期能量比率随着总晚期能量水平的变化而变化。结果表明，侧向能量比、背向能量比和架空晚期能量比对LEV的贡献程度不同。在大礼堂进行了客观测量，以明确晚期声音的方向性特征，这与听者的包络有关。定向传声器的测量值揭示了实际声场中横向、纵向和垂直晚期能量水平变化的范围。垂直分量的能级衰减系数最大。此外，为了考虑到达接收器的延迟声音的空间平衡，还考虑了定向延迟能量比。还应考虑后期反射的适当方向分布，以实现被声音图像包围的感觉。晚期声定向分布的最佳条件还有待进一步研究。

The purpose of this study is to investigate the relation between the arrival direction of late sound and perceived listener envelopment (LEV). A series of psychological experiments were conducted with three-dimensional simulated sound fields in an anechoic chamber. Firstly, the effect of late energy arriving from four fundamental directions on perceived LEV was individually investigated. The results show that the lateral sound level gives the highest correlation with LEV, while late sound arriving from overhead and behind the listener also correlates to LEV very strongly and positively. Secondly, the experiments were conducted to make clear the degree of contribution of directional energy components of late sound to LEV. The results show that not only lateral level but also the late sounds from behind and overhead affect LEV significantly. Furthermore, directional late energy ratios were varied with a constant level of total late energy. From the result, the degree of contribution of lateral, back and overhead late energy ratios to LEV was found. Objective measurements were performed in auditoria to clarify the directional characteristics of late sounds, which correlated with listener envelopment. The measured values with directional microphones reveal the ranges of the level variation of lateral, longitudinal and vertical late energy in real sound fields. It is also found that the level attenuation coefficient of vertical component is highest. Furthermore, directional late energy ratios are considered in order to account for the spatial balance of late sound arriving at a receiver. A proper directional distribution of late reflections should also be considered in order to realize the feeling of being surrounded by sound images. Further research on the optimum conditions for the directional distribution of late sound is needed.