Tinnitus is the perception of sound when there is none present. It is most often described as "ringing in the ears" but varies from person to person. Some people hear hissing, buzzing, whistling, roaring, high-pitched screeches, or a sound like steam escaping from a radiator. Still others hear one tone or several tones. Twelve million Americans suffer from a severe case of tinnitus and it has been estimated that 20% of the population experiences tinnitus at some time in their lives.

Initially, a person suffering from tinnitus may be worried or frightened because she is unsure what is wrong or how serious is the condition. Although tinnitus itself is not life threatening, some tinnitus sufferers describe the constant noise as irritating while others describe it as maddening. The actual medical cause of tinnitus is not clear but it is believed that some factors such as exposure to loud noise may produce or worsen tinnitus.

Tinnitus maskers alleviate tinnitus by masking out the perceived sound of tinnitus. Conventional tinnitus maskers produce sound of their own to help mask the tinnitus sound. Perhaps the simplest tinnitus masker is a cassette or compact disk player that plays soothing background sounds like rain or surf. It is believed some sufferers find relief because they are able to focus on these soothing sounds and "tune out" the tinnitus sounds. Other conventional tinnitus maskers generate sounds at selected frequencies to cancel out the tinnitus sounds.