When a SINE TONE or COMPLEX TONE is played loudly enough, additional HARMONICs will be heard that are not present in the original tone. These added tones, being frequency multiples of the original tone, are called aural harmonics.
Like COMBINATION TONES, aural harmonics are a form of DISTORTION caused by non-LINEAR processing of the INNER EAR.
See also: HETERODYNE. Compare: DIFFERENCE TONE, OVERTONE, PARTIAL, SIDEBAND, SUMMATION TONE.