Before introducing natural sounds to potentially improve the soundscape quality, it is important to understand how key contextual factors (i.e. expected activities and audio-visual congruency) affect the soundscape in a given location. In this study, the perception of eight natural sounds (i.e. 4 birdsongs, 4 water sounds) at five urban recreational areas under the constant influence of road traffic was explored subjectively under three laboratory settings: visual-only, audio-only, and audio-visual. Firstly, expected socio-recreational activities of each location were determined in the visual-only setting. Subsequently, participants assessed the pleasantness and appropriateness of the soundscape at each site, for each of the eight natural sounds augmented to the same road traffic noise, in both audio-only and audio-visual settings. Interestingly, it was found that the expected activities in each location did not significantly affect natural sound perception, whereas audio-visual congruency of the locations significantly affected the pleasantness and appropriateness of the natural sounds. Particularly, the pleasantness and appropriateness decreased for water sounds when water features were not visually present. In contrast, perception with birdsongs was unaffected by their visibility likely due to the presence of vegetation. Hence, audio-visual coherence is central to the perception of natural sounds in outdoor spaces.

在引入自然声音以潜在地改善音景质量之前，重要的是要了解关键的背景因素（即预期活动和视听一致性）如何影响给定位置的音景。在这项研究中，在三种实验室环境下，主观探索了在道路交通不断影响下五个城市娱乐区的八种自然声音（即4种鸟鸣，4种水声）的感知：纯视觉，纯音频和有声视觉的。首先，在仅视觉环境中确定每个位置的预期社会娱乐活动。随后，参与者在纯音频和视听环境中，针对八种自然声音中的每种声音，在相同的交通噪声下进行了评估，从而评估了每个站点的声景的舒适度和适当性。有趣的是 结果发现，每个位置的预期活动都不会显着影响自然声音的感知，而这些位置的视听一致性会显着影响自然声音的愉悦性和适当性。特别地，当视觉上不存在水特征时，水声的愉悦性和适当性降低。相反，鸟类鸣叫的感知不受可见性的影响，这可能是由于植被的存在。因此，视听连贯性对于感知室外空间中的自然声音至关重要。当在视觉上不存在水特征时，水声的愉悦性和适当性降低。相反，鸟类鸣叫的感知不受可见性的影响，这可能是由于植被的存在。因此，视听连贯性对于感知室外空间中的自然声音至关重要。当在视觉上不存在水特征时，水声的愉悦性和适当性降低。相反，鸟类鸣叫的感知不受可见性的影响，这可能是由于植被的存在。因此，视听连贯性对于感知室外空间中的自然声音至关重要。