Qi Meng

Effect of sound-related activities on human behaviours and acoustic comfort in urban open spaces

Human activities are important to landscape design and urban planning; however, the effect of sound-related activities on human behaviours and acoustic comfort has not been considered. The objective of this study is to explore how human behaviours and acoustic comfort in urban open spaces can be changed by sound-related activities. On-site measurements were performed at a case study site in Harbin, China, and an acoustic comfort survey was simultaneously conducted. In terms of effect of sound activities on human behaviours, music-related activities caused 5.1-21.5% of persons who pass by the area to stand and watch the activity, while there was a little effect on the number of persons who performed excises during the activity. Human activities generally have little effect on the behaviour of pedestrians when only 1 to 3 persons are involved in the activities, while a deep effect on the behaviour of pedestrians is noted when >6 persons are involved in the activities. In terms of effect of activities on acoustic comfort, music-related activities can increase the sound level from 10.8 to 16.4dBA, while human activities such RS and PC can increase the sound level from 9.6 to 12.8dBA; however, they lead to very different acoustic comfort. The acoustic comfort of persons can differ with activities, for example the acoustic comfort of persons who stand watch can increase by music-related activities, while the acoustic comfort of persons who sit and watch can decrease by human sound-related activities. Some sound-related activities can show opposite trend of acoustic comfort between visitors and citizens. Persons with higher income prefer music sound-related activities, while those with lower income prefer human sound-related activities.

Influence of social and behavioural characteristics of users on their evaluation of subjective loudness and acoustic comfort in shopping malls.

A large-scale subjective survey was conducted in six shopping malls in Harbin City, China, to determine the influence of social and behavioural characteristics of users on their evaluation of subjective loudness and acoustic comfort. The analysis of social characteristics shows that evaluation of subjective loudness is influenced by income and occupation, with correlation coefficients or contingency coefficients of 0.10 to 0.40 (p<0.05 or p<0.01). Meanwhile, evaluation of acoustic comfort evaluation is influenced by income, education level, and occupation, with correlation coefficients or contingency coefficients of 0.10 to 0.60 (p<0.05 or p<0.01). The effect of gender and age on evaluation of subjective loudness and acoustic comfort is statistically insignificant. The effects of occupation are mainly caused by the differences in income and education level, in which the effects of income are greater than that of education level. In terms of behavioural characteristics, evaluation of subjective loudness is influenced by the reason for visit, frequency of visit, and length of stay, with correlation coefficients or contingency coefficients of 0.10 to 0.40 (p<0.05 or p<0.01). Evaluation of acoustic comfort is influenced by the reason for visit to the site, the frequency of visit, length of stay, and also season of visit, with correlation coefficients of 0.10 to 0.30 (p<0.05 or p<0.01). In particular, users who are waiting for someone show lower evaluation of acoustic comfort, whereas users who go to shopping malls more than once a month show higher evaluation of acoustic comfort. On the contrary, the influence of the period of visit and the accompanying persons are found insignificant.

The influence of crowd density on the sound environment of commercial pedestrian streets

Commercial pedestrian streets are very common in China and Europe, with many situated in historic or cultural centres. The environments of these streets are important, including their sound environments. The objective of this study is to explore the relationships between the crowd density and the sound environments of commercial pedestrian streets. On-site measurements were performed at the case study site in Harbin, China, and a questionnaire was administered. The sound pressure measurements showed that the crowd density has an insignificant effect on sound pressure below 0.05 persons/m2, whereas when the crowd density is greater than 0.05 persons/m2, the sound pressure increases with crowd density. The sound sources were analysed, showing that several typical sound sources, such as traffic noise, can be masked by the sounds resulting from dense crowds. The acoustic analysis showed that crowd densities outside the range of 0.10 to 0.25 persons/m2 exhibited lower acoustic comfort evaluation scores. In terms of audiovisual characteristics, the subjective loudness increases with greater crowd density, while the acoustic comfort decreases. The results for an indoor underground shopping street are also presented for comparison.

Effects of individual sound sources on the subjective loudness and acoustic comfort in underground shopping streets

Previous studies have demonstrated that human evaluation of subjective loudness and acoustic comfort depends on a series of factors in a particular situation rather than only on sound pressure levels. In the present study, a large-scale subjective survey has been undertaken on underground shopping streets in Harbin, China, to determine how individual sound sources influence subjective loudness and acoustic comfort evaluation. Based on the analysis of case study results, it has been shown that all individual sound sources can increase subjective loudness to a certain degree. However, their levels of influence on acoustic comfort are different. Background music and the public address system can increase acoustic comfort, with a mean difference of 0.18 to 0.32 and 0.21 to 0.27, respectively, where a five-point bipolar category scale is used. Music from shops and vendor shouts can decrease acoustic comfort, with a mean difference of -0.11 to -0.38 and -0.39 to -0.62, respectively. The feasibility of improving acoustic comfort by changing certain sound sources is thus demonstrated.

Effect of temporary open-air markets on the sound environment and acoustic perception based on the crowd density characteristics

The sound environment and acoustic perception of open-air markets, which are very common in high-density urban open spaces, play important roles in terms of the urban soundscape. Based on objective and subjective measurements of a typical temporary open-air market in Harbin city, China, the effects of the temporary open-air market on the sound environment and acoustic perception were studied, considering different crowd densities. It was observed that a temporary open-air market without zoning increases the sound pressure level and subjective loudness by 2.4dBA and 0.21dBA, respectively, compared to the absence of a temporary market. Different from the sound pressure level and subjective loudness, the relationship between crowd density and the perceived acoustic comfort is parabolic. Regarding the effect of a temporary open-air market with different zones on the sound environment and acoustic perception, when the crowd densities were the same, subjective loudness in the fruit and vegetable sales area was always higher than in the food sales area and the clothing sales area. In terms of acoustic comfort, with an increase in crowd density, acoustic comfort in the fruit and vegetable sales area decreased, and acoustic comfort in the food sales area and the clothing sales area exhibited a parabolic change trend of increase followed by decrease. Overall, acoustic comfort can be effectively improved by better planning temporary open-air markets in high-density urban open spaces.

Evaluation of Sound Environment in the Waiting Halls of Railway Stations

Nowadays, the users’ evaluation of sound environment in the railway stations is focused by all kinds of experts. Comparing with other spaces, the waiting hall is usually recognized as the most important space in the railway station. In this study, more than 600 questionnaire survey has been undertaken at 4 waiting halls of railway stations in capital cities of China, to determine how the sound sources and sound pressure level influence acoustic evaluation. More details of acoustic evaluation in the waiting hall of Harbin railway station are given in this paper. Based on the analysis of the investigation results, it has been found that in the waiting halls of railway stations, PA system is generally noticeable and ‘masking’ other less preferred sound sources, while sound from mobiles is preferred by passengers. The relationship between the measured LAeq and the subjective loudness, acoustic comfort evaluation as well as subjective loudness and acoustic comfort are all of a linear shape, and the acoustic comfort is general better when LAeq is lower than 75dBA.

Subjective Evaluation of Acoustic Environment in Underground Spaces

Previous studies have demonstrated that users’ evaluation of acoustic environment such as subjective loudness or acoustic comfort depends on a series of factors in a particular space, rather than only on sound pressure levels. In this study, more than 2800 interviews have been undertaken at underground spaces in Harbin, China, to find out influencing factors to users’ evaluation, considering both space conditions and demographical factors. Based on the analysis of case study results, it has been found that in underground spaces, background music is generally noticeable and preferred, and it is useful for psychologically ‘masking’ other less preferred sound sources. While there is a linear correlation between the measured LAeq and the subjective loudness, the relationship between the measured LAeq and the acoustic comfort evaluation is of a parabolic shape, and the acoustic comfort is the best when LAeq is around 65-70dB. There is no significant difference between different age groups, whereas people with a higher income level tend to feel that an underground space is nosier and less acoustically comfortable.

A Field Study Method for Soundscape in Railway Stations

Present, railway stations are rather common in every cities, towns and villages. In this study, the field study method of soundscape in railway stations has been developed, aiming at finding out the relationships between users’ evaluation of sound environment and other factors in such spaces, as well as their similarities and differences with other urban public spaces. Based on sociological theory, questionnaires and simpling methods have been designed. Using these methods, soundscape surveys and measurement have been carried out in 4 railway stations in capital cities, China, considering both staffs and passengers. By analysing the data, some initial results are given in this paper for further research.

Effect of Users' Social Characteristics on Soundscape in the Waiting Halls of Railway Stations

It has been demonstrated in previous studies that the evaluation of soundscape was influenced by some social characteristics of persons. In this study, more than 600 questionnaire surveys were undertaken at waiting halls of 4 railway stations in capital cities of China, to determine how the users’ social characteristics influence their evaluation of soundscape. These results show that the relationships between evaluation of acoustic and gender or age are not significant (p>0.1), but female passengers were more careful on evaluation of sounscape. The acoustic comfort was influenced by income and education, with correlation coefficient is -0.35 and -0.32 (p<0.01), respectively, while subjective loudness was influenced by education and occupation, with correlation coefficient is 0.35 and -0.51 (p<0.01), respectively. This study can enhance the understanding of aural environment in railway stations and also can help architects using social characteristics design the better spaces for evaluation of acoustics in the waiting halls of railway stations.

The Influence of Users' Behavioral Characteristics on Soundscape in the Waiting Halls of Railway Stations

It has been demonstrated in previous studies that the evaluation of soundscape was influenced by not only social characteristics but also some behavioral characteristics of persons. In this study, more than 600 questionnaire survey has been undertaken at waiting halls of 4 railway stations in capital cities of China, to determine how the users’ behavioral characteristics influence their evaluation of soundscape. The results show that the relationships between evaluation of acoustics and passengers’ waiting time, rest or partners is not significant (p>0.1), but visiting times (p<0.01). The evaluation of subjective loudness is the highest, when waiting time at 1.5 to 2 hours, while evaluation of subjective loudness is general lower at other time. The evaluation of acoustic comfort is more different between sitting and standing, when waiting time at 0.5 to 1 hour. The passengers with no partner will give general higher acoustic comfort at first (<0.5 hours), but give lower acoustic comfort at following time.