Signal to Noise Ratio of the Announcement from Reinforced Sound System and Background Noise in Transportation Facility

Abstract

This study investigated signal to noise ratio (S/N) of the signal sound and announcement in transportation facilities such as subway and railway station, bus-terminal and airport. The result of survey in subway station showed that 82% of participants were dissatisfied with the signal sound and announcement. Acoustical characteristic and S/N of the signal sound and announcement were also analysed after measuring the signal sound, announcement, train arriving noise and background noise in transportation facilities. In the subway station, the S/N ratios ranged from –14.4~13.8 dB and mostly were lower than 10 dB, which is suitable value for word recognition of elderly person. The S/N ratio in the railway station ranged from 0.7 to 5.7 dB, and the ratio in the bus terminal and airport was 8.4 dB and 9.2 dB, respectively. For the subway station, the S/N ratio in separated platform was 2 dB higher than that of island platform, and the ratio in platform with screen door was about 7 dB higher than that in platform without screen door.