Concepedia

Abstract

Several professional mimics selected by audition from a large group, were given intensive training on utterances of the eight “customers” in Doddington's 40speaker population [J. Acoust. Soc. Amer. 49, 139 (A) (1971)]. The training method uses an interactive DDP-516 computer to provide the mimic with immediate playback of his practice utterances as well as immediate A-B comparison between his own and customer utterances. Recordings of the best utterances from the best four mimics were processed by the computer verification system described previously [Doddington, op cit., and R. C. Lummis, J. Acoust. Soc. Amer. 50, 106(A) (1971)]. The system uses five features for verification: pitch, level, first, second, and third formant frequencies. If the acceptance-rejection criterion that yields equal-error performance in Doddington's speaker population is used for the mimics, 27% of the best utterances by the best mimics would be accepted. This acceptance rate compares to 1.2% for nonmimicking impostors. Extensions to the verification procedure are being studied that will make successful mimicry more difficult.