What is reverberation of sound?

Reverberation: A sound created in a big hall will persist by repeated reflections from the walls of the hall until it is no longer audible.The repeated reflection that results in this persistence of sound is called reverberation.

To reduce reverberation, the roof and walls of the auditorium are generally covered with sound-absorbent materials like compressed fibre board, rough plaster or draperies. The seat materials are also selected on the basis of their sound absorbing properties.