The act of reverberating; especially, the act of reflecting light or heat, or reëchoing sound; as, the reverberation of rays from a mirror; the reverberation of rays from a mirror; the reverberation of voices; the reverberation of heat or flame in a furnace.
When a sound is produced in a room, and then stops, the ear does not normally perceive a sudden silence. There may be a gradual decline in sound, or there might be one or more echoes, all caused by reflections of sound from the inner surfaces of the room. When sound gradually decays, the effect is called 'reverberation and the length of time it takes a loud sound to die away completely is called the 'reverberation time.' Reverberation times of 1 second or more are necessary in churches. Echoes, that is, quiet periods followed by recurrences of the former sound, destroy speech intelligibility; they can be avoided by proper room design.