Changes of Human Voice Caused by Age, Disguise, and Simulation
W. Endres · The Journal of the Acoustical Society of America · 1971
In order to clarify whether visible speech spectrograms can be used to identify human beings, two questions must be studied: Does the formant structure of phonomes uttered by a certain speaker change over a longer interval of time? Can the formant structure be changed by disguise or is it even possible to imitate the formant structure of another speaker? Spectrograms of phonemes uttered by seven speakers and recorded over periods of up to 29 years showed that the position of formants and of the pitch of voiced sounds shifts to lower frequencies with increasing age of test persons. Speech spectrograms of texts spoken in a normal and a disguised voice revealed strong variations of formant structure. Visbile speech spectrograms of utterances of VIPs have been compared with those of imitators. The imitators succeeded in varying the formant structure and the pitch frequency of their voices, but they were not able to adapt these parameters to those of the imitated persons. In addition, a report is given on the results gained by comparing the voices of twins and their relatives.