Listener envelopment refers to the sensation of being surrounded by sound, either by multiple direct sound events or by a diffuse reverberant sound field. More recently, a specific attribute for the sensation of being covered by sound from elevated directions has been proposed by Sazdov et al. and was termed listener engulfment. This contribution investigates the effect of the temporal and directional density of sound events on listener envelopment and engulfment. A spatial granular synthesis technique is used to precisely control the temporal and directional density of sound events. Experimental results indicate that a directionally uniform distribution of sound events at time intervals $\Delta t < 20$ milliseconds is required to elicit a sensation of diffuse envelopment, whereas longer time intervals lead to localized auditory events. It shows that elevated loudspeaker layers do not increase envelopment, but contribute specifically to listener engulfment. Lowpass-filtered stimuli increase envelopment, but lead to a decreased control over engulfment. The results can be exploited in the technical design and creative application of spatial sound synthesis and reverberation algorithms.

翻译：聆听包围感指听众被声音包围的感知，这种包围可源于多个直接声事件或弥散混响声场。近期，Sazdov等人提出了一种特定属性——来自上方方向的覆盖感，并将其命名为聆听吞没感。本研究探讨了声事件的时间密度和方向密度对聆听包围感与吞没感的影响。采用空间颗粒合成技术精确控制声事件的时间与方向密度。实验结果表明：当时间间隔$\Delta t < 20$毫秒时，方向均匀分布的声事件可诱发弥散包围感，而较长的时间间隔则导致局部听觉事件。研究显示，增加上方扬声器层不会增强包围感，但会显著贡献于聆听吞没感。低通滤波刺激可增强包围感，但会削弱对吞没感的控制能力。该成果可应用于空间声合成与混响算法的技术设计及创意实践。