A spectrograph transforms the energy used in the production of speech into a visual graph of acoustical energy. The spectrogram of an unidentified speaker is compared with that of an identified speaker in order to find similar patterns. The majority of the courts which have considered the question have ruled that voiceprint evidence is admissible. See United States v. Smith, 869 F.2d 348, 351 (7th Cir. 1989); United States v. Williams, 583 F.2d 1194 (2d Cir. 1978), cert. denied 439 U.S. 1117 (1979). Although the District of Columbia Circuit has held that voice print evidence is inadmissible, see United States v. Addison, 498 F.2d 741 (D.C. Cir. 1974), the continuing validity of that determination is questionable in view of the Supreme Court's subsequent decision addressing the admissibility of scientific evidence in Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993).
Updated May 20, 2015