References and Resources

Audio Loudness Standards, Recommendations and Guidelines

Reference ID Title Date Notes
July 2023
Comprehensive recommendations based on AESTD1008.
E-health multimedia systems, services and applications – Safe listening
June 2022
Requirements for safe-listening devices and systems (personal/portable audio systems, especially those for playing music) to protect from hearing loss. Glossary and background on sound, hearing and hearing loss.
Recommendations for Loudness of Internet Audio Streaming and On-Demand Distribution
September 2021
Latest AES guidelines on Distribution Loudness for streaming, on-demand and voice response systems. Successor to AESTD1004.
Loudness in Streaming
June 2021
Supplement to R128 for Streaming
Loudness Parameters for Short-Form Content
August 2020
Defines and specifies the values for advertisements, promos etc.
Loudness Normalisation and Permitted Maximum Level of Audio Signals
August 2020
The European Broadcasting Union’s primary document for radio and television. Brief, but includes links to 9 EBU and ITU reference documents with details.
Loudness Standard for Over-the-Top Television and Online Video Distribution for Mobile and Fixed Devices
January 2020
Covers devices, mobile or fixed, that receive OTT and OVD services. It describes management of loudness and dynamic range within a device, with or without the use of metadata.
Recommended Practice Loudness Guidelines for Over-the-Top Television and Online Video Distribution
July 2018
Guidelines based on AESTD1006.
Sound system equipment: headphones and earphones associated with personal music players - Maximum sound pressure level measurement methodology - Part 3
As the title indicates, this defines SPL measurement of consumer headphones and earphones and European exposure limits to protect hearing.
September 2016
Audio Guidelines for Over the Top Television and Video Streaming
Requirements for loudness and true-peak indicating meters
Loudness Guidelines for OTT and OVD Content
October 2017
The successor to AESTD1005. Guidelines for audio loudness of online video content, prepared by the AGOTTVS Study Group
Practical guidelines for distribution systems in accordance with EBU R 128
July 2016
Audio processing and transmission for radio as well as home receivers and video playout equipment
Loudness Metering. ‘EBU Mode’ Metering to supplement loudness normalization in accordance with EBU R 128
January 2016
Definitions of Integrated, short-term and momentary loudness. Describes ITU’s test signals for testing and calibration of loudness meters and measurement software.
Loudness Range: A measure to supplement loudness normalisation in accordance with EBU R 128
January 2016
Details on the algorithm, measurement and application of Loudness Range (LRA).
Practical guidelines for Production and Implementation in accordance with EBU R 128
January 2016
A large paper on strategies for normalization and leveling in production. Surround and stereo downmix corrections are covered, as well as alignment level and listening sound pressure level.
Algorithms to measure audio programme loudness and true-peak audio level
October 2015
Latest in series of standards that define algorithms to measure audio program loudness and true-peak audio level, a method of measuring the Integrated Loudness over entire program segments etc.
ATSC Recommended Practice: Techniques for Establishing and Maintaining Audio Loudness for Digital Television
March 2013
Guidance to broadcasters and creators of audio for TV content. Developed originally to describe loudness management for ATSC 1.0, it recommends production, distribution, and transmission practices.
Guidelines for audio loudness of online video content, prepared by the AGOTTVS Study Group
January 2012
Some requirements for audio metering devices that implement the loudness and true-peak algorithms specified in other ITU-R Recommendations.

Audio Loudness References

Title Author Date Notes
R. Byers
August 2021
Best practices for loudness measurement and normalization in audio storytelling production.
R. Byers
August 2021
Discussion of differences in using loudness measurement and normalization in radio and podcast production.
G. Ogonowski
October 2020
Discussion of audio sample rates and effects near full scale.
S. Norcross
October 2020
Study showing that subjects on average tend to match music content 3-4 dB higher than the speech-based reference signal when measured similar in loudness by ITU-R BS.1770.
Apple Developer article
Paper provides a model to improve accuracy of speech-gated loudness measurement when speech activity is low.)
E. Grimm
October 2019
4.2 million albums were analyzed for loudness aspects such as loudest and softest track loudness. Evidence of development of the loudness war was found
J. Starzynski
National Association of Broadcasters Engineering Handbook, 11th Ed., pp. 767-790
C. Bertin
SPL protection limits from WHO and ITU standards.
T. Lund
June 2015
Test results of SPL from real music players and headphones. Warns that consumers are at risk of hearing damage without limits on exposure.
J. Kean, E. Sheffield
April 2015
Investigation of dynamic range desired by listeners in range of environmental noise conditions with speakers and headphones.
H. Robjohns
February 2014 (Sound On Sound)
As ITU loudness becomes known, recognized mastering engineer Bob Katz considers the implications for those who make, mix and master music.
T. Lund
For five years, the author has systematically studied audio capabilities of Pod and Mobile TV devices... Taking test results and perceptual criteria into account, guidelines are given for optimum station handling of programs for Mobile devices.
F. Begnert, H. Ekman, J. Berg
October 2011
Study showing that normalization may yield different perceived loudness between program types.
E. Skovenborg, T. Lund
October 2008
Loudness range tolerance of listeners: for diagnosing potential problems in ingest material; as a quality check after processing, editing; for use in content delivery.
E. Skovenborg, S. Nielsen
October 2004
Fundamental evaluation of models of loudness perception before ITU BS.1770.
J. Riedmiller,
October 2003
Early studies of listener needs for consistent audio loudness in broadcast TV, satellite and cable television services.
E. Benjamin
October 2002
Comparison of methods for making objective measurements designed to correlate better with actual loudness (A-weighting, etc.)
Speech Levels in Various Noise Environments
K. Persons,
Speech Levels in Various Noise Environments
Soulodre, et al.
October 2023
Subjective tests to evaluate the perceived loudness of a broad variety of typical program materials.
G. Soulodre,
S. Norcross
October 2003
Metrics for rating the performance of objective loudness measures are evaluated.
G. Soulodre
May 2004
How the ITU-R is investigating objective measures for the perceived loudness of various broadcast program materials.

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