2014 Volume 38 Issue 2 Pages 123-131
The municipal public address (M.P.A.) system for disaster prevention is an important information facility in communities. The speech intelligibility of such a system, however, tends to be deteriorated by multi-path echoes with long time delay owing to reflections from nearby buildings and by the sounds from loudspeaker systems covering other subareas. When designing such an M.P.A. system, a tool effective for the prediction of outdoor sound propagation should be developed. For this aim, the authors have been investigating the applicability of a computer modeling technique based on geometrical acoustics. In addition, auralization is also desirable to assess the speech intelligibility of the M.P.A. system in acoustic design process. As a method for this purpose, the authors have been developing a simulation method in which the sounds calculated by the computer modeling are reproduced through a 6-channel reproduction system to realize spatial impression. As a result, it has been found that this simulation method is effective to investigate the sound propagation from an M.P.A. system with spatial information and can be used for auditory experiment to examine the speech intelligibility.
