Transient (acoustics)
In acoustics and audio, a transient is a high amplitude, short-duration sound at the beginning of a waveform that occurs in phenomena such as musical sounds, noises or speech. Transients do not necessarily directly depend on the frequency of the tone they initiate. It contains a high degree of non-periodic components and a higher magnitude of high frequencies than the harmonic content of that sound.
Transients are more difficult to encode with many audio compression algorithms, causing pre-echo.Sonar
The term transient is used by military sonar operators to describe unexpected sounds emanating from another vessel such as operating machinery, a metal hatch being slammed, or the flooding and pressurization of torpedo or vertical launch tubes.
