Notion of psychoacoustic perception
Introduction to auditorium acoustics

Figure 8, based on the work of the English acoustician M. Barron, summarizes the various perceptible effects as a function of the delay of a single reflection and its level relative to that of the direct sound.

The following considerations apply:

• Below the threshold line, the reflection causes no perceptible effect.

• High-amplitude, strongly delayed reflections cause a sensation of frank echo that is generally very unpleasant. (Not to be confused with the term echo, used by some musicians to express the...