ASTM E3150-18(2023)
(Guide)Standard Guide for Forensic Audio Laboratory Setup and Maintenance
Standard Guide for Forensic Audio Laboratory Setup and Maintenance
SIGNIFICANCE AND USE
4.1 The design and configuration of an audio laboratory, as well as the maintenance of equipment, are factors that must be considered to ensure an optimal environment to produce the best results. This guide is intended to provide general guidance for laboratory setup and maintenance.
4.2 This document is not meant to be an all-inclusive guide on how to set up a laboratory; nor does it contain information pertaining to specific commercial products as it relates to computer hardware, forensic, and non-forensic software applications.
4.3 When dealing with equipment and technology outside your area of expertise, consult with an appropriate specialist.
SCOPE
1.1 This guide sets forth recommendations for the creation of a forensic audio laboratory space as well as the configuration, verification, and maintenance of the equipment contained within the lab.
1.2 In designing and configuring an audio laboratory, it is important to consider the acoustical environment/room of the laboratory, as well as climate control. Other than having a viable location for the laboratory, computer hardware and software applications are the most important components of a laboratory.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E3150 − 18 (Reapproved 2023) An American National Standard
Standard Guide for
Forensic Audio Laboratory Setup and Maintenance
This standard is issued under the fixed designation E3150; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2.3 AES Standard:
AES Recommended Practice for Audio Preservation and
1.1 This guide sets forth recommendations for the creation
Restoration – Storage and Handling – Storage of
of a forensic audio laboratory space as well as the
Polyester-Base Magnetic Tape, AES Standard 22-1997,
configuration, verification, and maintenance of the equipment
Reaffirmed 2008
contained within the lab.
2.4 SWGDE Standard:
1.2 In designing and configuring an audio laboratory, it is SWGDE Recommendations for Validation Testing
important to consider the acoustical environment/room of the
3. Terminology
laboratory, as well as climate control. Other than having a
viable location for the laboratory, computer hardware and
3.1 Definitions:
software applications are the most important components of a
3.1.1 For definitions of terms that may assist in interpreting
laboratory. this standard, refer to Terminology E1732.
1.3 This standard does not purport to address all of the
4. Significance and Use
safety concerns, if any, associated with its use. It is the
4.1 The design and configuration of an audio laboratory, as
responsibility of the user of this standard to establish appro-
well as the maintenance of equipment, are factors that must be
priate safety, health, and environmental practices and deter-
considered to ensure an optimal environment to produce the
mine the applicability of regulatory limitations prior to use.
best results. This guide is intended to provide general guidance
1.4 This international standard was developed in accor-
for laboratory setup and maintenance.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the 4.2 This document is not meant to be an all-inclusive guide
on how to set up a laboratory; nor does it contain information
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical pertaining to specific commercial products as it relates to
computer hardware, forensic, and non-forensic software appli-
Barriers to Trade (TBT) Committee.
cations.
2. Referenced Documents
4.3 When dealing with equipment and technology outside
your area of expertise, consult with an appropriate specialist.
2.1 ASTM Standards:
E1732 Terminology Relating to Forensic Science
5. Audio Laboratory Considerations
2.2 ISO/IEC Standard:
5.1 Environment—The physical environment, independent
ISO/IEC 17025 General Requirements for the Competence
of equipment, in and around a forensic audio laboratory can
of Testing and Calibration Laboratories
have a profound effect on the quality of work produced. Audio
laboratory design is a complex task and comprehensive refer-
ences should be consulted, including Refs (1-4).
This guide is under the jurisdiction of ASTM Committee E30 on Forensic
5.1.1 Acoustics—The acoustic environment of a forensic
Sciences and is the direct responsibility of Subcommittee E30.12 on Digital and
audio laboratory is the collection of ambient sounds and
Multimedia Evidence.
influences (for example, materials, resonances, echo), which
Current edition approved Nov. 1, 2023. Published November 2023. Originally
approved in 2018. Last previous edition approved in 2018 as E3150 – 18. DOI:
10.1520/E3150-18R23.
2 4
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Available from Audio Engineering Society, Inc. (AES), International
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Headquarters, 551 Fifth Ave., Suite 1225, New York, NY 10176, http://
Standards volume information, refer to the standard’s Document Summary page on www.aes.org.
the ASTM website. Available from the Scientific Working Group on Digital Evidence (SWGDE),
Available from International Organization for Standardization (ISO), ISO https://www.swgde.org.
Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier, The boldface numbers in parentheses refer to a list of references at the end of
Geneva, Switzerland, http://www.iso.org. this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E3150 − 18 (2023)
can affect the quality of a forensic audio analysis. Eliminate or separate computer for searching the Internet for unique codecs,
minimize sound distractions in the audio laboratory to prevent proprietary players, etc.
confusion as to what sounds are present on a recording (5).
5.2.2 Audio Equipment—Choose playback, processing, and
5.1.1.1 Acoustical impediments: recording equipment suitable for the task at hand, using
professional and broadcast grade equipment where possible.
(1) Background conversation, TV, radio, and music;
(2) Computer and equipment cooling fans; 5.2.3 Signal Path—The signal path is the complete route of
(3) Air conditioning units and airflow; and the audio data from the source through all of the connectors,
(4) Vibration. interfaces, cables, and software to the destination. Design
signal paths with the least amount of degradation. Use cables
5.1.1.2 Steps can be taken to mitigate external noise in the
and connectors of sufficient quality and minimal length to
laboratory, such as
minimize signal loss and reduce the opportunity for interfer-
(1) Using acoustic foam or other materials to absorb
ence. For analog audio runs, maximize the use of balanced
reverberation and echo,
lines over unbalanced lines (10, 13). Avoid stacking adapters to
(2) Designing the laboratory with acoustic traps,
interconnect equipment. It is preferable to use a cable designed
(3) Rerouting unnecessary HVAC ducts,
for the particular interfaces involved. Be aware of the imped-
(4) Using acoustic baffling within the HVAC ducts that are
ance and level of analog interfaces (7). Loudspeakers are not
present,
recommended for conducting forensic audio analyses, but if
(5) Using heavy wooden doors that seal tightly all around
otherwise used during an examination, ensure that they are
when closed, and
capable of reproducing the full frequency spectrum of the
(6) Using high-quality headphones during examinations to
audio signal.
reduce extraneous sounds and maximize the audibility of the
5.2.4 Transmission Format—Choose the signal format that
signal being examined.
transmits the audio data with the least amount of degradation,
5.1.2 Temperature and Humidity—Ensure the temperature
loss, or attenuation. This decision depends upon what formats
and humidity of the laboratory is within the manufacturer’s
are available on the equipment being used. Minimize the
specifications of the equipment. Equipment itself generates
number of digital to analog and analog to digital conversions
heat and requires adequate ventilation to prevent heat buildup
(14, 15).
that could affect the signal (AES Recommended Practice for
Audio Preservation and Restoration, (6)).
5.3 System Verification—Once the equipment and intercon-
5.1.3 Electromagnetic Interference—Interference from a va-
nections are configured, updated, or changed, run test signals
riety of electromagnetic sources can affect signal quality
through the various components to verify that everything is
(7-
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.