Basically, noise is the unwanted signals interrupting the desired signals causing disturbances. It can be an additional signal within the system or a disturbance attached to the input signal. This noise has no pattern, nor does it have any constant frequency. The most common noises consist of flickers, buzzing sounds, and hissing. This noise can completely ruin the crisp and solid amplification of music. There are two basic types of noises as well: External and Internal. External noise sources cannot be completely eradicated. Internal noises also cannot be eliminated but can be reduced.