Voiceprint

Voiceprint, or speech spectrogram, visual record of the sound waves of a human voice made by running a tape recording of a voice through an instrument called a sound spectrograph. The sound spectrograph was developed in the 1940s by U.S. scientists at Bell Research Laboratories. Voiceprints are used in the study of speech and hearing disorders. Police use voiceprints for evidence in the prosecution of criminal cases.