DAMP or DAMPING
The loss of energy in a system due to friction (internal or external) or other resistance. The resulting decrease in AMPLITUDE of the system is known as the DECAY.
The term damping, then, is restricted to the system itself, rather than to the sound of the system in an environment where the word 'decay' can refer to the effect of REVERBERATION, i.e. to the decrease in acoustical energy in an enclosed space.
See: DECAY TIME, RATE OF DECAY. Compare: ABSORPTION, ATTENUATION, RESONANCE, RISE TIME, VIBRATION.
Exponential damping of a sine wave. Dashed line indicates exponential decay of the amplitude.