Dynamics describes the fluctuation and contrast in loudness levels throughout a piece of music or audio signal. It represents the emotional journey of a track, defined by the difference between its quietest passages and its loudest crescendos.

In musical notation, this is communicated through terms like piano (soft) and forte (loud). In the studio environment, "dynamics" also refers to the technical management of these amplitude variations. Engineers use dynamic processors (such as compressors and limiters) to manipulate the natural dynamic range of a performance, either to tame erratic volume spikes for a consistent sound or to expand the difference for greater dramatic effect.