Tinnitus masker issues associated with use of tinnitus maskers: the "safe" level of continuous sound depends on the duration of the sound. For maskers worn continuously, or most of the day, a safe level is no more than 70db, in accordance with EPA maximum safe exposure level for 24-hour environmental sound. Maskers louder than 45db or so (the ambient background level of an average home living area) may start to interfere with understanding conversation (about 60db). Masking of high frequency tinnitus (>6,000hz) is difficult because of the resonance characteristics of the human ear as well as high frequency limitations of in-ear devices.
Tinnitus masker 1970s by Dr. Jack Vernon, when he reported that white noise was effective in alleviating tinnitus. 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 After the sound is withdrawn, tinnitus may be fully (complete silence) or partially suppressed.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 silence followed by a gradual return of tinnitus to its original level. The effect lasts for 5 minutes or less