For reversal -- Chief Justice Weintraub, Justices Jacobs, Proctor, Hall and Mountain, and Judges Conford and Sullivan. For affirmance -- None. The opinion of the Court was delivered by Proctor, J.
This case brings the method of voice identification through the use of the spectrogram, the so-called voiceprint, before us once more. We previously considered this method in State v. Cary, 49 N.J. 343 (1967), on remand 99 N.J. Super. 323 (Law Div. 1968), remanded again 53 N.J. 256 (1969), aff'd 56 N.J. 16 (1970).
On March 31, 1967, the Middlesex County Grand Jury returned indictments against the defendants for threatening to do bodily injury to one Albert Soffer unless the sum of $7,400 should be paid to the defendants, in violation of N.J.S.A. 2A:105-4. Soffer subsequently informed the trial court that he would refuse to testify, even if cited for contempt, because he was fearful for his life and the lives of his family. The State alleges that the police recorded a
telephone conversation made in March, 1967 by Soffer from police headquarters. During that conversation, incriminating statements were allegedly made by the other party or parties to the conversation. The State seeks to compare the defendants' voices with the voice or voices engaged in the conversation through the use of the voiceprint method, and consequently moved for an order compelling defendants to submit to a voiceprint test. After receiving testimony from several witnesses, the trial judge denied the request, holding that the State had failed to meet its burden of establishing general scientific acceptance of the voiceprint method. The judge further found that the length of the five-year time span here involved -- from the recording of the original telephone conversation to the then current date -- precluded use of the method in any case. This Court granted the State's motion for leave to appeal before consideration by the Appellate Division.
Voiceprint analysis is a method of sound identification which utilizes the spectrograph machine. This machine decomposes the sound of the human voice into frequency components which are graphically recorded, thus producing the spectrogram or voiceprint. Voiceprints are then compared by persons trained in the use of the method for possible identification purposes. Although the machine was invented during World War II, it was not until the 1960's that Lawrence Kersta conducted experiments in spectrography at Bell Telephone Laboratories which convinced him that there were unique characteristics of each person's voice which could be used for reliable identification of individuals by spectrograms.
At the time we previously considered this development in State v. Cary, 49 N.J. 343 (1967), the scientific support for the validity of this voice identification method rested solely on the testimony of Kersta. We held that the testimony of one man alone would not be sufficient evidence to establish the reliability of the method's results. We believed it was unreasonable to compel the defendant to submit
to the test until more evidence was produced in support of the reliability of the method for accurate identification. The case was consequently remanded to the trial court for further testimony concerning the method's reliability. We said:
"An actual demonstration which shows the accuracy of the voiceprint process would be desirable. The testimony of experts in addition to Mr. Kersta who believe that voiceprint identification is scientifically sound would be helpful. Although we do not wish to dictate in advance the details of the hearing, we do feel that something more than the bare opinion of one man, however qualified, is required." 49 N.J. at 352.
On remand the State was unable to produce expert testimony to support the opinion of Kersta; the trial court held that testimony based on the voiceprint method of identification would not be admissible at trial, and therefore declined to compel the defendant to submit to the test. 99 N.J. Super. 323 (Law Div. 1968). We remanded the case once more in order to give the State additional opportunity to produce expert testimony, 53 N.J. 256 (1969), but it was unable to do so, and we affirmed, 56 N.J. 16 (1970).
Our reluctance to accept the voiceprint method in Cary on the basis of the testimony of Kersta alone was later supported by scientists who criticized his experiments. See Ladefoged and Vanderslice, "The 'Voiceprint' Mystique," Working Papers in Phonetics (U.C.L.A. 1967); Bolt, and five others, "Speaker Identification by Speech Spectrograms: A Scientists' View of its Reliability for Legal Purposes," 47 Journal of Acoustical Society of America 597 (1970). The criticisms of Kersta were directed to his conclusion that the voiceprint method was sufficiently reliable for legal purposes. Kersta's critics believed that the restricted nature of his experiments ...