Tinnitus maskers are a range of devices based on simple white noise machines used to add natural or artificial sound into a tinnitus sufferer's environment in order to mask or cover up the ringing. The noise is supplied by a sound generator, which may reside in or above the ear or be placed on a table or elsewhere in the environment. The noise is usually white noise or music, but in some cases, it may be patterned sound or specially tailored sound based on the characteristics of the person's tinnitus. The perceived loudness of tinnitus, called sensation level (SL), is how much louder the tinnitus is above the ambient noise of the environment. By raising the ambient level of noise (playing white noise into the ear), the apparent loudness of tinnitus is reduced. The noise level is close to and usually somewhat louder than the perceived loudness of the tinnitus. The generated noise is designed to be a calming, less intrusive sound than the ringing or hissing of tinnitus. Depending on the loudness of the noise, tinnitus may be fully or partially masked. Tinnitus masking cannot reduce or eliminate tinnitus, only reduce awareness of it. The efficacy of a tinnitus masker may depend on the wearer's capacity to experience residual inhibition, the temporary suppression of tinnitus in response to particular sound patterns. The mechanism of sound masking can be explained by analogy with light. In a dark room where someone is turning a lamp on and off, the light will be obviously noticeable. However, if the overhead lights are turned on, turning on the lamp will no longer be as distracting because it has been "masked". While sound masking is an effective solution for a majority of those with tinnitus, it does not work for everyone. History The concept that an external sound could suppress perception of an internal one was first realised clinically in the mid 1970s by Dr. Jack Vernon, when he reported that white noise was effective in alleviating tinnitus. Suppression vs. masking Tinnitus suppression is different than but related to tinnitus masking. It is an acoustic or neurological effect that results in temporary suppression of tinnitus by listening to an appropriately tailored sound for a short period. After the sound is withdrawn, tinnitus may be fully (complete silence) or partially suppressed. Most (70–90%) of persons can experience the effect. There is usually a period of complete