Editing Noise (section)

== Recording and reproduction ==
In audio, [[Sound recording and reproduction|recording]], and [[broadcast]] systems, audio noise refers to the residual low-level sound (four major types: hiss, rumble, crackle, and hum) that is heard in quiet periods of program. This variation from the expected pure sound or silence can be caused by the audio recording equipment, the instrument, or [[ambient noise level|ambient noise]] in the recording room.<ref>{{Cite web|url=http://www.audioshapers.com/blog/audio-noise.html|title=Audio Noise-Hiss, Hum, Rumble & Crackle|website=AudioShapers|access-date=2016-06-23}}</ref>

In [[audio engineering]] it can refer either to the acoustic noise from loudspeakers or to the unwanted residual electronic noise signal that gives rise to acoustic noise heard as hiss. This signal noise is commonly measured using A-weighting or [[ITU-R 468 weighting]]

Noise is often generated deliberately and used as a [[test signal]] for audio recording and reproduction equipment.