Waveform of a cymbal crash.
In music, a transient is a sudden change in sound output – an increase or decrease – which occurs for a short period of time, often a small fraction of a second. Transients have a rapid attack and decay – that is, they have steep wave-fronts – and are associated with such sounds as a drum stroke, cymbal hit, or acoustic-guitar pluck.
Transient response is the ability of a component to respond quickly and accurately to transients. Transient response affects reproduction of the attack and decay characteristics of a sound.