Noise Definition - What is Noise?
Noise refers to distortion or interference in a signal. When you turn an analog TV to a "fuzzy" channel, the fuzz is caused by noise interfering with the television signal. The same is true when there is static, buzz, hum, or other unwanted interference in an audio signal. Noise can be caused by improper mixing or volume control, or from other unwanted electrical signals interfering with the electrical signal carrying the audio. For example, power wires running near speaker wires can cause static or distortion to come out of the speakers.