The quick changing of amplitude envelope (amplitude modulation) is the inherent properties of speech signals. They are analyzed by the auditory system and are reflected in the auditory sensation as a sequences of some "events", that participate in creating of phonetic images. The dynamics of frequency distribution of events is considered to be used by listeners as a determinants of some consonants. However, this supposition are inconsistent with the psychoacoustics experiments showed that listeners can't determine the frequency of amplitude irregularities of tonal components. Current work consists of the discussion of this problem and results of experiments where the perception of an amplitude jumps in different frequency format area was studied using the synthetic quasi--syllable. The results obtained give evidence that the phoneme interpretations "know" the frequency of amplitude irregularieties.