Environment of Railway Station by Field Measurement and Subjective Experiment

In a railway station, an appropriate announcement is very important for users' convenience and safety. In Japan, reflective materials are generally selected as finishing materials in consideration of durability and fire performance. Consequently, there is a high probability that background noise is easy to get louder and the announcement is difficult to understand due to reverberation in many of railway stations. In this study, we conducted both a filed survey and a subjective experiment. Sound environments of 8 railway stations were measured. Moreover, the subjective test was designed to evaluate listening difficulty and loudness of the announcement. The measured announcements were reproduced in an anechoic room with a 3D sound field simulation system using a 6 ch. recording / reproduction technique. The results were as follows. LAeq values of the background noise were ranged between 65 and 70 dB at most measuring points. The levels of announcements depended on its contents and the measuring points. The largest level difference at the same measuring point was about 9.5 dB. The result of the listening difficulty was related to S/N ratio. In addition, when the 50% of subjects reported the announcement was difficult to listen, the S/N ratio was +12 dB.