比较 to 噪音 which is 讨厌 声 a 信号 is any 声 or 信息 which is 意味 to be 聆听 to 测量 or 储存

In 声音景观（声景） 研究 声 信号 are always treated in 关系 to their 周围 or 基调 语义（上下文） since they 补充 that 语义（上下文） in the same way figure and ground are 相关 in 视觉 感知 Thus a 研究 of 信号 also 揭露 重要 信息 about the 整体 声 环境

声 信号 may be 研究 in any of the 跟随 ways
on the 基础 of their acoustic 特征 which may represent a 识别 代码 or other 模式 关于（附属） to their 使用 主观 by their 个别 感知（认为） meanings 历史 according to their 演变 within a 特定 社会 语义（上下文） 比较 by 种类 and 功能（函数） in different cultures or 周期（时期） symbolically according to their 内涵 and 联合 meanings

声 信号 are 重要 in the way in which they regulate the life of a 团体 and reflect its character Those of 历史性 importance may be termed 声音标志（音标） The area over which a 声 信号 may be 听 is its profile or acoustic 空间 which may be regarded as its 球体（范围） of influence In 现代 城市 环境 many 团体 信号 are 消失 both 物理 and 声学（听觉） with rising 周围 噪音 电平/级别

源 adapted and summarised from Barry Truax - Handbook for Acoustic 生态学 CD-ROM Edition Cambridge Street 出版 1999 - CSR-CDR 9901