# Sound Environments in Large Public Buildings for Crowd Transit: A Systematic Review
## 3 Results
### Shopping Malls  
[PERSON] [37] surveyed two kinds of shopping mall spaces perceived as acoustically uncomfortable: one was the largest space in the centre containing restaurants and a sitting area for food stores, and the other was long corridors or galleries in which walls were glass facades containing boutiques, small cafes and local areas for short rest in Russia. The volume of five cases selected for the former ranged from 29,500 to 10,600 m\({}^{3}\), and the heights were between 9.2 to 18.2 m. The volume of three cases selected for the latter had ranged from 14,500 to 31,000 m\({}^{3}\), and the length was between 112 to 234 m. Results showed that at middle frequencies \(L_{\text{Aeq-1 min}}\) were 7 to 10 dB higher in occupied condition when compared to unoccupied one. Normal voice levels at a distance of 1 m were about 60 dB, raised voices created 65 to 70 dB. The largest measured \(T_{20}\) and \(T_{30}\) was found in the largest food court as 5.1 s, and the smallest one was obtained in the smallest gallery as 2.7 s. Two \(T\) thresholds and three ranges were proposed for assessments, and the necessities of the acoustic absorption materials were suggested for surfaces and volumes. No subjective surveys were performed to the present. [PERSON] et al. [38] surveyed three shopping malls, including the Tunjangan Plaza (retail area 160,000 m\({}^{2}\)), Grand City Mall (retail area 45,000 m\({}^{2}\)) in Surabaya, and Malioboro Mall (retail area 22,000 m\({}^{2}\)) in Yogyakarta, Indonesia, with both sighted and visually impaired participants. The measurements were carried out with the indoor soundwalks on three Saturdays, either around lunch or dinner time. \(L_{\text{Aeq-10 min}}\) were reported to be around 70 dB (\(L_{\text{AFFmax}}\): 90.5 dB, \(L_{\text{AFFmin}}\): 60.3 dB). Both off-site and in-situ surveys were used: A focus group discussion method was assigned for off-site to collect attributes as perceived by the participants, and then constructed in a closed-ended questionnaire for in situ. The questionnaire used three-point Likert scales and was subject-based. With sighted people, three soundscape dimensions were labelled as (1) \"pleasantness\" including \"good\", \"neat\", \"modest\", \"warm\", \"comfortable\" and \"like\"; (2) \"space\" including \"crowded\", \"messy\", and \"tight\"; and (3) \"facilities\" including \"complete\" and \"clear signage\". With visually impaired people, five soundscape dimensions were abstracted as (1) \"pleasantness\" including \"happy\", \"good\", \"luxurious\", \"modern\", \"comfortable\", and \"like\"; (2) \"space\" including \"spacious\" and \"large\"; (3) \"eventfulness\" including \"noisy\", \"loud\", and \"clamorous\";(4) \"danger\" including \"dangerous\"; and (4) \"direction\" including \"know the position\". It was concluded that pleasantness and space were the two most prominent factors for both participants. The visually impaired people perceived more favourably than the sighted, and they could perceive soundscape dimensions of danger and direction with the hearing sense alone. It is of interest to know the relationship between objective and perceptual attributes. The authors indicated that acoustic perceptions were more influenced by crowds compared to SPL. For sighted people, the more crowded the shopping mall, the higher SPL was perceived. For visually impaired people, the strongest correlation exists between _L_eq and \"noisy\". [PERSON] and [PERSON] [39] studied a large shopping mall in the very centre of Amman, Jordan, and chose shopping areas, entrances, food courts, and playing areas to explore the sound environment and its correlation to the acoustic comfort of the workers. \(L_{\text{Aeq-3 min}}\) were collected between 10:30 and 12:30, between 13:30 and 15:30, between 16:30 and 18:30, between 19:30 and 21:30 during the entire seven-day period. The values were measured as a minimum of 58 dB in the shopping area in the early morning and a maximum of 83 dB in the playing area in the evening.