Two tones presented together produce audible combination tones in the ear

Evidence

When two primary tones with the frequencies hand 12 are presented to an ear, additional tones with pitches correlated to the frequencies 12 - hand … 2h - 12 become audible (see Chap. 14). Such audible distortion products can be cancelled by adding a tone of corresponding frequency and correct level and phase. Such cancellation, based on psychoacoustical perception, is called hearing cancellation. Based on purely objective methods and apparatus, distortion product emissions can be measured in the closed outer ear canal by a sensitive microphone. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 330

Categorization

• DEFINE: Defines hearing cancellation versus objectively measured distortion product emissions as distinct phenomena.