# Effect of Audio-Visual Factors in the Evaluation of Crowd Noise
## 1 Introduction  
In many studies related to soundscapes, general evaluations of soundscapes are usually considered to be evaluations of sound levels, that is, the subjective evaluation of loudness, usually of background noise [1; 2; 3; 4; 5; 6]. Soundscape evaluations are also considered to be evaluations of sound preferences, that is, evaluations of foreground sounds [7; 8; 9; 10; 11]. Individual sounds play an important role in the overall soundscape [12]. Therefore, evaluating sound preferences is crucial for determining the quality of a given space's acoustic landscape. Environmental psychologists point out that the implicit attributes of social/cultural factors are interrelated with the outward attributes of the physical environment with respect to their influence on people's perception of physical sound [13; 14]. In contrast to musical preferences that focus on the sound itself, judgment of everyday sounds is based on a collection of relevant information about our surroundings [8]. In urban public spaces, natural sounds and traffic noise are particularly concerning. Natural sounds usually play an active role in urban open spaces. They can improve one's cognitive state [15], help regulate mood, and promote feelings of pleasure. Regardingthe effect of natural sounds on sound quality, [PERSON] et al. showed that water sounds can effectively improve the overall perceived quality of a soundscape by masking park noise [16]. [PERSON], [PERSON], and [PERSON] showed that natural sounds in historic districts positively impact the perception of quiet and harmonious sounds [17]. [PERSON], [PERSON], and [PERSON] noted that people have a higher preference for natural sounds and melodies [18]. Conversely, traffic noise tends to play a negative role. For example, mechanical noise has been shown to affect human hearing and reduce stress recovery, leading to bad moods [19; 20; 21]. Relatively neutral sounds, such as human voices, should also be considered [22]. Human sounds are a special type of sound in which the source and receiver are both humans [23]. [PERSON] and [PERSON] indicated that human sounds contributed to an increase in both pleasantness and eventfulness in commercial streets [24]. Yet, human sounds may positively or negatively affect the sound environment. Under certain specific conditions, human sounds have positive effects. For example, the sound of children playing increases the pleasantness of the sound environment [20]. However, human voices also have negative effects. For example, the sound of children crying can increase negative emotions in people [21]. [PERSON] and [PERSON] demonstrated that human sound reduces the tranquility of a park but increases its vitality [25]. Eighty percent of human sensory experience relies on visual stimulation [26], so the correlation between landscapes and soundscapes has been extensively studied [16; 27; 28; 29]. Most studies on the auditory response to soundscapes have focused on the auditory properties of the landscape. However, while human perception relies heavily on visual factors, most landscape studies on the auditory response to soundscapes remain limited to analyzing auditory properties. Human perception of the environment is not generated by a single, isolated sense; rather, it is an inherently multisensory experience involving visual, auditory, olfactory, and other sensory stimuli interacting [30]. Visual and auditory domains interact with each other in influencing human perception and behavior [31]. Soundscape research is closely related to 'context,' and visual factors are an important part of the context. Therefore, by studying audio-visual interactions from the perspective of the soundscape, we can study the whole environment in a more auditory manner. Research of audio-visual interactions in the field of soundscapes includes both field and laboratory studies. Field studies consider soundscapes based on real places.