SONIC DECAY
Sonic decay refers to the progressive reduction in amplitude of a sound over time. It is a basic component of how a sound is defined. Decay is the time that it takes for a note to die away once the musician has stopped producing the sound. The sound waves dissipate in much the same manner as waves produced by tossing a stone in a pond. Decay is also a part of the envelope of a sound. Reverberation is created when a sound or signal is reflected, causing numerous reflections to build up and then decay as the sound is absorbed by the surfaces of objects in the space.