Irregular qualities of sound sources appeared at the input of the outdoor emergency mass notification sound system

In order to obtain an intelligible speech at a listening point addressed by the mass notification sound system, not only high transmission quality of the system, but also a sufficiently clear speech sound source is needed. However, the qualities of speech sources may not be constant because they are supplied by different types of production and transmission methods, e.g., the variety of speech source production methods causes various specifications and irregular qualities of sources, and some types of transmission methods between the parent station (speech production system) and children stations (acoustic amplification system) cannot convey the source signal with sufficient quality. In this presentation, the authors showed examples of irregular source quality appeared at the input of the acoustic amplification system and discussed the necessity of verifying the signals at several points in the total system (i.e., the system between the speech source and the listening point) to regulate their qualities. Then, the guidelines for the performance verification of the outdoor emergency mass notification sound systems which was published by the Acoustical Society of Japan was introduced.