Evaluation of the sound environment in a metro platform space based on audio-visual interaction experiments

In response to rapid urban development in China, subways have become a key component of urban transportation systems. The audio-visual environment of the most commonly used subway platforms has a significant effect on the emotions and health of the vast population that relies on subway travel. Taking the typical subway station space in Guangzhou as an example, four types of representative sounds and scene images were examined in this study. Audio-visual interaction experiments were conducted in the laboratory to explore the effects of visual and spatial elements in metro platform spaces on evaluations of the acoustic environment. The study found significant differences in the direction and degree of influence of different visual factors on various acoustic evaluations in subway platform spaces. Under acoustic-only condition, background music received the highest scores in the acoustic comfort, preference. However, these scores significantly decreased after platform images were added, while the quietness evaluation for the train arrival and departure sounds, broadcast sounds, and crowd activity sounds improved. In terms of visual factors, the impact of spatial brightness on acoustic evaluations was significantly greater than that of cool and warm colour tones or the spaciousness of the metro platform. An increase in brightness can significantly improve the three acoustic evaluations of broadcast sounds. The influence of colour tones and spaciousness on the evaluation of different sound types varied greatly. When the platform's scene changes from warm to cool tones, the comfort ratings for train arrival and departure sounds decreases significantly, whereas the quietness evaluations for broadcast sounds improve significantly. When the platform's spaciousness is reduced, the quietness of crowd activity sounds significantly decreases. The impact of visual factors on the evaluation of the acoustic environment follows the order of quietness > comfort > preference. Among various sounds, visual factors had the most significant impact on the evaluation of broadcast sounds. These results provide a direction for future research in terms of exploring the interaction between visual scenes and specific sound sources in traffic spaces and its influence on acoustic evaluation mechanisms.