Assessing the admissibility of a new generation of forensic voice comparison testimony

This article provides a primer on forensic voice comparison (aka forensic speaker recognition), a branch of forensic science in which the forensic practitioner analyzes a voice recording in order to provide an expert opinion that will help the trier-of-fact determine the identity of the speaker. The article begins with an explanation of ways in which human speech varies within and between speakers. It then discusses different technical approaches that forensic practitioners have used to compare voice recordings, and frameworks of reasoning that practitioners have used for evaluating the evidence and reporting its strength. It then discusses procedures for empirical validation of the performance of forensic voice comparison systems. It also discusses the potential influence of contextual bias and ways to reduce this. Building on this scientific foundation, the article then offers analysis, commentary, and recommendations on how courts evaluate the admissibility of forensic voice comparison testimony under the Daubert and Frye standards. It reviews past rulings such as U.S. v. Angleton, 269 F.Supp 2nd 892 (S.D. Tex. 2003) that found expert testimony based on the spectrographic approach inadmissible under Daubert. The article also offers a detailed analysis of the evidence presented in the recent Daubert hearing in U.S. v. Ahmed, et al. 2015 EDNY 12-CR-661, which included testimony based on the newer automatic approach. The scientific testimony proffered in Ahmed is used to illustrate the issues courts are likely to face when considering the admissibility of forensic voice comparison testimony in the future. The article concludes with a discussion of how proponents of forensic voice comparison testimony might meet a reasonably rigorous application of the Daubert standard and thereby ensure that such testimony is sufficiently trustworthy to be used in court

Telephone Transmission and Earwitnesses: Performance on Voice Parades Controlled for Voice Similarity.

The effect of telephone transmission on a listener's ability to recognise a speaker in a voice parade is investigated. A hundred listeners (25 per condition) heard 1 of 5 'target' voices, then returned a week later for a voice parade. The 4 conditions were: target exposure and parade both at studio quality; exposure and parade both at telephone quality; studio exposure with telephone parade, and vice versa. Fewer correct identifications followed from telephone exposure and parade (64%) than from studio exposure and parade (76%). Fewer still resulted for studio exposure/telephone parade (60%) and, dramatically, only 32% for telephone exposure/studio parade. Certain speakers were identified more readily than others across all conditions. Confidence ratings reflected this effect of speaker, but not the effect of exposure/parade condition.ESRC; British AcademyThis is the author accepted manuscript. The final version is available from Karger via http://dx.doi.org/10.1159/00043938

Can we have faith jurors listen without prejudice? Likely sources of inaccuracy in voice-comparison exercises

Reviews the legal position governing the circumstances under which fact-finders in criminal proceedings, particularly jurors, are allowed to listen to audio recordings in the context of a voice-comparison exercise for the purposes of identifying the speaker. Examines the estimator and system variables that may affect the exercise's accuracy, and suggests potential safeguards that could be introduced to reduce misidentification