The delay between the original sound and the first echo can be calculated using the distance between the sound source and the reflecting object divided by the speed of sound. The time the echoes arrive after the direct sound depends on the room’s dimensions. Some buildings (such as mosques) have been specifically designed to enhance echoes. Echoes occur when there is more than one repetition.
This is a single repetition of the sound source caused by the sound-wave coming against an opposing surface which reflects it. Perhaps the most obvious effect is when an echo occurs. The temporal properties of sounds are altered in different ways which depend on the dimensions of the room, its contents and the material on the walls.
