The 效果(效应) 产生 by 创作 and sometimes 增 during 回放 a gap of 时间 between two copies of one 录制 item When the difference is small the 效果(效应) is close to that of a sweeping 滤器 Augmenting the gap will lead to panoramic motions and further to 回声 源 - Rodolfo Caesar 1992 The 作曲 of 電聲學/电声学 樂/乐 PhD Thesis University of East Anglia