It is a well‐known psychophysical fact that phase changes in a three‐component signal are audible provided that the frequency separation between the components does not exceed a critical value. A possible source of these effects is the phase‐dependent level of the ’’internal components’’ caused by an interaction within the ear of acoustic frequency components and ’’combination tones’’ of the form (n+1)f1−nf2. The experiments described in this paper are intended to verify this hypothesis by both psychophysical and electrophysiological experiments. The level of the internal component as a function of phase was psychophysically estimated in a forward‐masking experiment. Besides, single cell recordings in the cochlear nucleus of the cat were performed to investigate the phase dependence. It has been possible to demonstrate the interaction between acoustic components and combination tones for both experimental approaches. It can be described as a vector addition. Subsequent psychophysical and electrophysiological experiments on the detectability limits of combination tones have shown that these limits correspond to the maximum frequency separations for the audibility of phase changes.