An echo is a repetition or a partial repetition of a sound due to reflection. Reverberation is also reflected sound, but in this case, separate repetitions of the original sound are not distinguishable. For a repetition to be distinct from the original, it must occur at least 50 ms afterwards without being masked by either the original signal or other sounds. In practice, an echo is more likely to be audible after a 100 ms delay. Very short delays cause an image shift sideways and tone colouration due to phasing; longer delays contribute to a spatial impression of reverberation, and stronger delays greater than 50 ms disturb the sound image and are perceived as echoes. (reduced from Barry Truax - Handbook for Acoustic Ecology CD-ROM Edition. Cambridge Street Publishing, 1999 - CSR-CDR 9901)
The delayed reflection of sounds in a stereo space.
术语顾问/Consultant to terminology