Speaker comparison involves analysing speech and voice patterns to assess the strength of evidence for or against two speakers being the same person. Typically, we are provided with two sets of recordings: a reference recording which is known to have come from a suspect and the evidential or questioned recording, related to a crime.
Forensic voice analysis
We are able to digitally transfer recordings from a range of audio devices and formats. Our scientific staff will examine and compare the voices on a number of phonetic and acoustic parameters. Alongside the best audio equipment, we use advanced acoustic software with in-house modifications for forensic analysis. We are also in the process of developing, testing and implementing automatic biometric systems for use in speaker comparison cases, which complement the analyses made by our experts.
Our methods are compliant with the Appeal Court rulings R -v- Anthony O’Doherty ( NICA 20) and R -v- Flynn & St John ( EWCA Crim 970). All our analyses are subject to quality control by a second expert.
We will provide a report which satisfies the guidelines for expert evidence in the relevant jurisdiction. Speaker comparison conclusions are stated in terms of support for the view that speakers in different recordings were the same, against the view that they were different speakers: in the form ‘the evidence provides strong support for the view that the questioned caller is the suspect’, for example. The scale of support statements used is that recommended by the (UK) Association of Forensic Science Providers.
Speaker comparison cannot provide the same strength of evidence as DNA, for example, so terms like ‘a match’ or ‘identification’ are not used. We make the limitations of the analyses clear in our reports and recommend that this evidence is used in conjunction with other evidence, as recommended by the International Association for Forensic Phonetics and Acoustics (IAFPA).
We have carried out speaker comparison in a huge number of cases. Some high-profile cases are provided in our example case archive.
Other terms include: speaker identification, speech comparison, voice identification, voice analysis, voice comparison, voice pattern analysis