# Sound Environments in Large Public Buildings for Crowd Transit: A Systematic Review
## 3 Results
### Transport Hubs/Stations  
[PERSON] et al. [46] took the recordings in 9 airports, 14 railway stations, 4 bus stations, and 7 subway stations (a total of 34) to explore the acoustic sequences on noise acceptance, that is, when the users were staying or walking in a transport hub, sequential sounds form sequence sounds sessions. The listening-test surveys, as an aspect of indoor soundscape research, extracted 209 sections of 30 s acoustic units. The acoustic units were divided into strong, medium, and weak levels, and compiled into 37 pieces of acoustic sequences, which were then subjected to four tests for acceptance evaluations using a 0-to-10 opinion scale. The effects of the acoustic sequence were demonstrated to improve the sound experience in such spaces. [PERSON] et al. [47] investigated acoustic comfort of six spaces, including seating area (11,100 m\({}^{3}\)), security check (180 m\({}^{3}\)), ticket check, ticket lobby (864 m\({}^{3}\)), restaurant (172 m\({}^{3}\)), and shop (288 m\({}^{3}\)) of Harbin railway station in China. \(L_{\text{Aeq-5 min}}\) were obtained between 8 a.m. and 6 p.m. with a one-hour interval. The questionnaire used five-point Likert scales surveying \"uncomfortable-comfortable\", \"noisy-quiet\", \"loud-soft\", \"low-high\", \"long-short\", and \"clear-unclear\". Results revealed that the comfort and communication level decreased with increasing SPL, which were all below 70 dB in the seating area, ticket lobby, and shops. The restaurants were noisiest at 75.1 dB, and comfort was rated higher than those in ticket check. The mean value of comfort in the railway station was acceptable as 3.65. However, comfort in the seating area and shop were higher as 3.81 and 3.91, respectively, and those in the restaurant were lower as 3.28. The seating area, shop area, and ticket lobby were quieter, and the areas with high concentrations of users were \"noisy\". \(T\) was related to space scale: the larger the space is, the longer it is. As it increased, comfort and communication level increased. Participants felt reverberation in space when it exceeded 4.5 s.  
[PERSON] and [PERSON] [48] selected the park, station entrance, and underground platform of Akkopru metro station in Turkey. The station was 895 m in length and 216 m in width. The height of the entrance level was 3.19 m and the height of the platform level was 3.36 m from the base to the suspended aluminium ceiling, and 7.33 m from the metro rails to the top of the metro tunnel. The methodologies involved the measurements of \(L_{\text{Aeq-15 min}}\), soundwalks with noise annoyance and \(L_{\text{Aeq-30s}}\), and listening tests on the relationships between space recognition and sound marks. The in-situ measurements were conducted on Saturday afternoon. Results show that noise levels were similar between 55 to 60 dB in the park and station entrance, while annoyance was higher in the station entrance. On the underground platform, \(L_{\text{Aeq}}\) were lower than those at the station entrance, yet annoyance was close. The listening test asked the participants to describe the recorded space from 17 perceptual adjective pairs and define the sound sources. Only half of the participants were able to correctly determine the function of the spaces; for indoor spaces, they chose words most frequently as \"unpleasant\", \"stressing\", and \"artificial\". [PERSON] et al. [49] investigated six subway stations across seasons in Seoul, South Korea, to explore thermal, air, light, acoustic, and passengers' overall comfort. The results concerning the acoustic comfort were only reported with two cases, of which the depths of the concourse were 6.0 and 8.0 m, and those of platform (two-platform form) were 10.2 and 23.1 m, respectively. In summer, noise levels were 67.9 and 63.3 dB in the concourses, and 65.3 and 62.9 dB on the platforms. In Fall, noise levels were reported to be 64.8 and 63.3 dB in the concourses, and 64.2 and 61.7 dB on the platforms.