Cancellation methods quantify the ear’s internally produced difference tones

Evidence

For quantitative psychoacoustical measurement of the nonlinear distortion products (mainly difference tones) produced in our hearing system, two methods are available ~ the method of cancellation and the pulsation-threshold method. The cancellation method uses an additional tone produced by the electronic equipment to have the same frequency as the difference tone, but being variable in amplitude and phase. This separately produced difference tone is added to the two primaries delivered to our hearing system. The subject adjusts the level and phase of this additional tone until the audible difference tone totally disappears. This way, the audible difference tone produced by our hearing system is cancelled. The level of the additional tone necessary for cancellation is a measure of the amplitude of the difference tone produced internally by our hearing system. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1530

Categorization

• DEFINE: Explains the cancellation method for measuring internally produced distortion products.
• corroborated: 2 independent passages support this claim — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1530