Reverberation
Continuous reflections of sound waves in a room, as opposed to the discrete echo.
What it means
Reverberation arises when sound waves in an enclosed space are reflected many times by walls, ceiling and floor. These reflections follow one another so closely that we do not hear them individually but as a fading of the sound. After the sound source falls silent, the room goes on sounding for a while.
A characteristic quantity is the reverberation time: the time in which the sound level falls by 60 decibels after the source stops. It depends on the size and shape of the room and on its materials. The American physicist Wallace Clement Sabine developed the basis for calculating it around 1900.
Musical use
A concert hall for orchestral music needs a reverberation that joins the sound and makes it warm without blurring it. Churches often have long reverberation times that carry chant and organ but make fast music unclear. In studio production, reverberation is created artificially with reverb units or software.
Reverberation should be distinguished from the echo, in which a single reflection arrives so late that we hear it as a separate repetition.
Performance practice
Adapt your playing to the room: in reverberant rooms play or sing more clearly and somewhat more slowly, in dry rooms with more expression in the sound. Listen to the room while warming up before you fix tempo and articulation.