Recommendation ITU-T H.870 (03/2022) Guidelines for safe listening devices/systems
Summary
History
FOREWORD
Table of Contents
Introduction
1 Scope
2 References
3 Definitions
     3.1 Terms defined elsewhere
     3.2 Terms defined in this Recommendation
4 Abbreviations and acronyms
5 Conventions
6 Safe listening: Introduction
     6.1 Background
     6.2 Personal audio system
          6.2.1 Consideration of headphones and earphones
          6.2.2 Note on individuality
          6.2.3 Guidance on measurement
7 Damage risk criteria
     7.1 Operational modes
     7.2 Uncertainty in dose estimate
8 Measurement methods
     8.1 Dosimetry
          8.1.1 Main related standards
          8.1.2 Definition of dose in the context of acoustic dosimetry
          8.1.3 Testing of dosimeter functionality
9 Sensitivity range and frequency response of headphones
10 Profiles
11 Health communication
     11.1 Purpose of including health communication as part of the standards for safe listening personal audio systems
     11.2 Key recommendations for communication as part of standards for safe listening devices
          11.2.1 Device interface user information
               11.2.1.1 Personal usage information
               11.2.1.2 Messages
          11.2.2 General information
          11.2.3 Information through means other than the device itself:
               11.2.3.1 User manual
               11.2.3.2 Packaging
               11.2.3.3 Website and advertising
12 Ambient noise control
     12.1 Passive attenuation of the background noise
     12.2 Active noise reduction of background noise
     12.3 Benefits of noise-isolating earphones
     12.4 Safety concerns associated with noise-isolating earphones
13 Volume control
     13.1 Volume limiting
     13.2 Password-protected volume control
14 Guidance on ancillary concerns
Appendix I  Status report
Appendix II  Dose estimation functionality for implementation in a personal audio system
     II.1 Introduction
     II.2 Main related standards
     II.3 Definition of dose in the context of acoustic dosimetry
     II.4 Weighting of different frequencies
     II.5 Signal capture point in a personal audio system (PAS)
     II.6 Handling of left and right channels
     II.7 Dosimeter implementation example
     II.8 Handling of computational complexity
     II.9 Handling of dose over days and weeks
     II.10 Case of unknown headphone characteristics
     II.11 Alternative audio signal capture point
     II.13 Uncertainties
Appendix III  European Standard EN 71-1 for toys
Appendix IV  "Music" versus "noise"
Appendix V  On stapedius muscle reflex
Appendix VI  Consideration of recovery phase
Appendix VII  Example of health communication
     VII.1 Recommendations to develop warnings and cues for action messages for device interfaces
     VII.2 Suggested flow (an example) of information as part of standards for safe listening devices
     VII.3 Example of how the information on listening parameters can be conveyed to the user
          VII.3.1 Information on use of weekly allowance
          VII.3.2 Information on how the user has used the allowance on any day
          VII.3.3 Listening time
     VII.4 Warnings and cues for actions
          VII.4.1 Examples of warnings and cues based on weekly use
          VII.4.2 Examples of messages based on daily use
          VII.4.3 Examples of messages with positive versus negative frame; and emotional versus rational appeal
Appendix VIII  Mechanism of hearing and impact of impact of sound
     VIII.1 Sound and waves
     VIII.2 Mechanism of hearing and hearing loss
     VIII.3 Measurement of sound energy
          VIII.3.1 Pressure
          VIII.3.2 Decibels
               VIII.3.2.2 dB SPL
               VIII.3.2.3 dBA
               VIII.3.2.4 dBFS
               VIII.3.2.5 dBHL
     VIII.4 Equal energy principle
Bibliography
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