(3) Reverberation is the phenomenon of persistence of sound after it has been stopped as a result of multiple reflections from surfaces such as furniture, people, air etc. within a closed surface. These reflections build up with each reflection and decay gradually as they are absorbed by the surfaces of objects in the space enclosed. It is the same as echo, but the distance between source of sound and also the obstacle through which it gets reflected is more or less in case of this reverberation. The phenomenon of reverberation is utilised by the producers of live or recorded music in order to enhance the sound quality.