Optimization of speech presentation in mass-notification sound systems based on word intelligibility

Abstract

Outdoor mass-notification sound systems can effectively convey emergency announcements over a wide area without requiring the audience to use any special devices. However, the intelligibility of speech presented via these systems is often severely degraded by long-path echoes. Under such conditions, it is important to consider robust ways of presenting speech information. Various studies have highlighted that there are many factors which affect the speech intelligibility with long-path echoes. We have focused on the effect of word familiarity and inserting pauses between the words in a speech signal. High-familiarity words are easy to understand even when presented under challenging listening conditions. By inserting pauses, speech intelligibility could be improved because more of the speech signal can be received without significant overlapping long-path echoes. In this study, speech materials were modeled based on actual sentences used in emergency notifications given via the Japanese mass-notification ...