Denis Smalley has 介绍 this 术语 as a 中项 of 描述 the 级 or 度 to which listeners perceptually relate 声 to real or imagined 物理 and gestural 源 within an 聞/幻听 聆 situation 代理 may 描述 the 识别 of 熟悉 instrumental or vocal 制作 when reproduced in 录制 形（曲）式 As the 度 of 代理 becomes more 遥控 listeners may ascribe imagined causes to 声 and their spectromorphological 演变 or apprehend the 声波 as 'abstract' Smalley 术语 these 变化 级 as 'orders of surrogacy'