Effects of the telephone on perceived voice similarity: implications for voice line-ups

Authors

  • Francis Nolan University of Cambridge
  • Kirsty McDougall University of Cambridge
  • Toby Hudson University of Cambridge

DOI:

https://doi.org/10.1558/ijsll.v20i2.229

Keywords:

voice similarity, voice line-ups, voice parades, earwitness identification, telephone transmission

Abstract

This study is relevant to forensic cases where an earwitness claims to be able to remember and identify a voice, and, more generally, to voice recognition. Given that a voice may have been heard over the telephone, it is important to know the effects of the telephone on voice quality. In particular we may ask whether the perceptual distance between two voice samples is affected by telephone transmission. In this paper the effects of the telephone are tested by an experiment using fifteen speakers of Standard Southern British English from the DyViS database of accent-matched young adult male speakers. For each possible pairing of speakers (including same-same pairs) twenty listeners heard a short speech sample from each of the two speakers and were asked to rate the distance between the two voices on a scale of 1 (very similar) to 9 (very different). The speech samples had been recorded simultaneously in both studio and telephone quality and were heard in ‘studio only’, ‘telephone only’, and ‘mixed (telephone and studio)’ pairs. Average similarity ratings across all speaker pairings for the three media conditions showed that the same pairs of voices are judged to be more similar when recorded over the telephone than at full bandwidth. When presentation qualities are mixed the voices sound more different for the listener; it is likely that the different transmission characteristics are being conflated with the voice differences. Implications for forensic cases are discussed.

Author Biographies

Francis Nolan, University of Cambridge

Francis Nolan is Professor of Phonetics in the Department of Theoretical and Applied Linguistics at the University of Cambridge. His research interests range over phonetic theory, intonation, connected speech processes and speaker characteristics. His long-standing involvement in forensic phonetics covers both fundamental research and casework, including expert speaker identification and the use of voice parades. He believes that forensic phonetic practice needs to be underpinned by advances in phonetic theory, and the problems posed by forensic phonetics in turn stimulate the development of phonetic theory. He is a founding member of IAFPA and President of the British Association of Academic Phoneticians.

Kirsty McDougall, University of Cambridge

Kirsty McDougall is a British Academy Postdoctoral Fellow in the Department of Theoretical and Applied Linguistics, University of Cambridge, and Fellow and Director of Studies in Linguistics at Clare College, Cambridge. She was previously a Research Associate on the forensic phonetics projects DyViS and VoiceSim. Her research interests include speaker characteristics, theories of speech production, phonetic realisation of varieties of English, and forensic phonetics. She is a member of IAFPA.

Toby Hudson, University of Cambridge

Toby Hudson is a research assistant in the Education First Research Unit in the Department of Theoretical and Applied Linguistics, University of Cambridge. He has a B.A. and an M.Phil. in Classics from the University of Cambridge. Among other research projects, he has previously worked on the forensic phonetics projects DyViS and VoiceSim. His research interests are in all aspects of phonetics and phonology, especially forensic phonetics, language acquisition, language technology, and the documentation of endangered languages. He is a member of IAFPA.

Published

2013-12-17

How to Cite

Nolan, F., McDougall, K., & Hudson, T. (2013). Effects of the telephone on perceived voice similarity: implications for voice line-ups. International Journal of Speech, Language and the Law, 20(2), 229–246. https://doi.org/10.1558/ijsll.v20i2.229

Issue

Section

Articles

Most read articles by the same author(s)

1 2 > >>