A sound also has an amplitude, a property subjectively heard as loudness.The amplitude of a sound is the measure of the displacement of the air pressure wave from its mean, or quiescent state.

• 声音有振幅；振幅的主观感觉是声音的大小.；声音的振幅大小取决于空气压力波距平均值(也称平衡态)的最大偏移量