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NCJ Number: 251608 Find in a Library
Title: Advancing Audio Forensics of Gunshot Acoustics
Author(s): Robert C. Maher
Corporate Author: Montana State University
United States of America
Date Published: April 2018
Page Count: 11
Sponsoring Agency: Montana State University
Bozeman, MT 59715
National Institute of Justice (NIJ)
Washington, DC 20531
US Dept of Justice NIJ Pub
Washington, DC 20531
Grant Number: 2014-DN-BX-K034
Sale Source: US Dept of Justice NIJ Pub
810 Seventh Street, NW
Washington, DC 20531
United States of America
Document: PDF
Type: Grants and Funding; Program/Project Description; Report (Grant Sponsored); Report (Study/Research); Research (Applied/Empirical)
Format: Document; Document (Online)
Language: English
Country: United States of America
Annotation: In addressing the need for improved scientific understanding of audio forensic evidence, particularly the analysis and interpretation of recorded gunshot sounds, the primary goal of this research was to create an apparatus and methodology for scientific and repeatable collection of firearm acoustical properties recorded without early sound reflections (anechoically).
Abstract: The project succeeded in obtaining good, repeatable gunshot recordings by using the specialized audio recording equipment and the standardized firearm test procedure. Researchers designed, built, and implemented a test rig that contained omnidirectional instrumentation microphones placed at 15-degree intervals on a semi-circular arc of 3-meter radius. A high-speed multichannel digital audio recorder served each microphone. Each firearm tested was fired from the center of the arc while the microphone system simultaneously and synchronistically recorded the acoustical wave forms from each angular position. The project involved the following seven components: 1) assembling and testing the microphone mounting system; 2) performance of the first round of gunshot recordings; 3) analysis of the new recording for consistency and reliability; 4) analysis of shot-to-shot variability; 5) analysis of muzzle-blast duration; 6) comparison of signal level as a function of azimuth and selected firearm; and 7) initial work on modeling and identification. It is now critical for forensic examiners in their gunshot interpretation to understand the strengths and weaknesses of the audio recording systems used in mobile audio recorders, particularly the miniature digital voice recorders carried by many law enforcement officers. 9 figures, listings of 8 scholarly products and 4 layman’s articles, and the website for the database
Main Term(s): Forensic sciences
Index Term(s): Acoustic environment; Evidence collection; Gunshot Sensors; National Institute of Justice (NIJ); NIJ final report
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