Forensic Audio: An Introduction

What is Forensic Audio (Audio Forensics)?

The word 'forensic' is defined as, "Pertaining to, connected with, or used in courts of law or public discussion and debate." (The Random House Dictionary of the English Language, Second Edition - Unabridged. Random House, Inc.,1987). Hence, the term 'forensic audio' may be defined as the application of audio knowledge, technologies and methodologies to questions of civil and criminal law or public discussion and debate.

Forensic audio, or audio forensics, traces its roots to the need to identify recorded and broadcast voices during World War II. One of the first forensic audio techniques, the time-frequency-amplitude (t-f-a) spectrographic "voiceprint," was developed in 1941. Thereafter, newer and more powerful forensic audio techniques have figured prominently in such infamous cases as the John F. Kennedy assassination (to answer such questions as, "How many gun shots were there?", "What was the time interval between shots?" and "Was one of the shots an echo?") and the Nixon 'Watergate tapes' scandal ("How did the 18 minute gap get there, and what information was erased?").

Forensic sciences, including forensic medicine, forensic anthropology and forensic audio involve the application of sophisticated technologies and scientific methodologies to historical, criminal and civil investigation. Technologies and methodologies of forensic audio include the following specialty areas:

5. Sound identification
6. Event sequence analysis
7. Dialogue decoding
8. Other signal analysis

1. Voice identification
2. Audibility analysis
3. Enhancement
4. Authenticity analysis