Studies on the optimum transmission of speech and acoustic information in public spaces-For universal design of acoustic environment-

本研究的目标是优化公共空间中的语音和声音信息的传输，同时考虑到设计以达到每个人的最佳状态，即通用设计。本研究的结果摘要如下：1.公共场所环境声的实际测量为了阐明估计背景噪声声学特性的方法，在地铁站和机场进行了实际测量。研究结果表明：(1)地铁车站背景噪声的A加权等效声级和频率特性可以通过每天的载客量进行粗略估计。(2)本研究测得的机场声学特性与中型地铁站的声学特性相似。本研究建议使用“听力难度等级”来评估言语传输性能，“听力难度等级”是言语传输性能的一种主观测量。听力测试的结果表明，听力难度等级比现有的主观测量方法更能敏感地评价言语传输性能。其他几项听力测试的结果表明：(1)声音的空间特征不影响听力难度。(2)通常的声学客观测量可以估计听力难度等级。(3)在本研究测试的混响和噪声声场中，年轻人和老年人的语音水平都是最优的。公共场所公告用语熟悉度的基础研究调查了公共场所公告中实际使用词语的家族性。结果显示，现场公告中使用的词语的熟悉度似乎低于公告手册中列出的公告实例中使用的词语。

The goal of the present study is to optimize transmission of speech and acoustic information in public spaces, with consideration of the design to achieve optimal conditions for everyone, that is, universal design. The summaries of the results of the present study are as follows.1. Actual measurements of environmental sounds in public spacesTo clarify the method for estimating acoustical characteristics of background noise, actual measurements at subway stations and an airport were performed. The results showed that: (1) A-weighted equivalent sound level and frequency characteristics of background noise in subway stations can be roughly estimated by numbers of passengers per day. (2) Acoustical characteristics of the airport measured in the present study were similar to that of medium-scale subway stations.2. Evaluation of speech transmission performance using “listening difficulty ratings"“Listening difficulty ratings," which is a subjective measure of speech transmission performance, is suggested in the present study. The result of listening tests demonstrates that listening difficulty ratings can evaluate speech transmission performance more sensitively than existing subjective measures. The results of other several listening tests showed that: (1) spatial characteristics of sounds did not affect listening difficulty. (2) Usual acoustical objective measures can estimate listening difficulty ratings. (3) The optimal speech levels for both the young and the aged were found in reverberant and noisy sound fields tested in the present study.3. Fundamental studies on familiarity of words used in announcements in public spacesFamiliarity of words actually used in announcements in public spaces was surveyed. The results showed that the familiarity of words used in live announcements seemed to be lower than that used in the examples of announcement which are listed on announcement manuals.