Assistive Listening Knowledge Base

Technology

Infrared

Questions and sources on infrared assistive listening, which carries sound on invisible light to receivers worn with earphones or a neckloop.

Introduction

Infrared assistive listening carries a venue's sound on infrared light, modulated onto subcarriers such as 2.3 and 2.8 MHz, from emitters in the room to receivers that listeners borrow and use with earphones or a neckloop1,2. No hearing aid receives it directly: listeners need a receiver, which telecoil users can wear with a neckloop3. The signal travels by line of sight and does not pass through walls, which keeps the sound in the room but means emitters need a clear path to listeners4,2. Sunlight and incandescent or halogen lamps add noise at the receiver, so infrared is impractical outdoors in daylight and rooms with large windows need screening or extra emitters5,1. Sources differ on glass: Listen Technologies says its infrared signal cannot pass glass, and Williams AV that its 2024 transmitter cannot be concealed behind glass6,7. An expert guide says windows must be covered to keep the sound confidential, and a UK maker advises pointing radiators away from windows because infrared does not reflect off most glass1,8.

In the US, the 2010 ADA Standards define assistive listening systems to include infrared, and their advisory notes say infrared is typically the better choice where confidential transmission is important, while FM may suit some open-air assemblies better9. In 2006 a US Access Board advisory committee recommended infrared as the preferred system for courtrooms, also because privacy matters there10. Digital multichannel infrared transmission is standardised in IEC 61603-7, written for conference interpretation, which uses subcarriers from 45 kHz to 1 MHz and from 2 to 6 MHz11.

Questions

The questions that report evidence on infrared, including the shared ones on codes, receivers, neckloops, telecoils and what listeners prefer (also listed under Shared).

See these questions in the tracker, with its filters

Sources

74 sources in the library report on infrared, newest first, with undated web pages last.

  • 9 independent
  • 17 manufacturer
  • 4 standards body
  • 16 nonprofit advocacy
  • 8 trade body
  • 20 government

See these sources in the evidence library, with its filters

Sources of the introduction

  1. Comparison of Large Area Assistive Listening Systems. Compton-Conley C. Hearing Loss Association of America (reprint), 2015. Nonprofit advocacy (reprinted by HLAA with the contact address of its Get in the Hearing Loop program; written by Cynthia Compton-Conley, PhD, of Gallaudet University; who paid for the original is not stated) ↩︎ https://www.hearingloss.org/wp-content/uploads/comparison-of-large-area-assistive-listening-systems.pdf
  2. Infrared, FM and Audio Over WiFi. RNID. RNID (Royal National Institute for Deaf People), 27 May 2026. Nonprofit advocacy (RNID, UK charity) ↩︎ https://rnid.org.uk/information-and-support/technology-and-products/assistive-listening/infrared-fm-and-audio-over-wifi/
  3. Coupling Options: Ways to Connect to Assistive Listening System Audio. Kaneb A (credited on the chart). Hearing Loss Association of America (HLAA), 2026. Nonprofit advocacy (Hearing Loss Association of America, a US consumer organisation for people with hearing loss; the chart is credited to Andrea Kaneb and names no funder) ↩︎ https://www.hearingloss.org/wp-content/uploads/documents/advocacy-resources/hlaa-coupling-options-als-chart.pdf
  4. Infrared (IR) Assistive Listening Systems. Center for Hearing Access. Center for Hearing Access, The John G. Shedd Institute, undated (read 9 October 2026). Nonprofit advocacy (Center for Hearing Access, an initiative of The John G. Shedd Institute for the Arts; it states that it accepts no donations from hearing-related vendors) ↩︎ https://centerforhearingaccess.org/infrared/
  5. Interference Problems of Fluorescent Lamps Operating on High Frequency Electronic Ballasts with Infrared Remote Control Equipment and Infrared Simultaneous Interpretation System. Wu M (Martin Wu Kwok-tin). Energy Efficiency Office, Electrical and Mechanical Services Department, Hong Kong SAR Government, August 2003. Government (Electrical and Mechanical Services Department, Hong Kong SAR Government; written by a department engineer) ↩︎ https://www.emsd.gov.hk/filemanager/en/content_764/infrared_interference_emsdweb.pdf
  6. Why Use Infrared? The Unique Benefits of ListenIR for Privacy and Security. Listen Team (Listen Technologies). Listen Technologies (blog), 10 October 2025. Manufacturer (Listen Technologies, which sells the ListenIR products described as well as FM, hearing loop, Wi-Fi and Auracast systems) ↩︎ https://www.listentech.com/secure-infrared-assistive-listening-listenir/
  7. IR T3 Infrared Transmitter user manual (MAN 295). Williams AV, 6 November 2024. Manufacturer (Williams AV, maker of the SoundPlus IR T3 transmitter described) ↩︎ https://williamsav.com/wp-content/uploads/2024/11/MAN-295-IRT3-User-Manual.pdf
  8. IRMTX750 Infra Red Modulator & Radiator: Installation and Maintenance Manual (Revision 2). Current Thinking Ltd. Current Thinking Ltd (Infra~Hear range); copy hosted by a French audiovisual reseller, January 2011. Manufacturer (Current Thinking Ltd, a UK maker of the Infra~Hear infrared assistive listening products described) ↩︎ https://www.la-bs.com/Objets/IRMTX750_me.pdf
  9. 2010 ADA Standards for Accessible Design. US Department of Justice. US Department of Justice (ada.gov), 15 September 2010. Government (US Department of Justice) ↩︎ https://www.ada.gov/law-and-regs/design-standards/2010-stds/
  10. Justice for All: Designing Accessible Courthouses (recommendations from the Courthouse Access Advisory Committee). Courthouse Access Advisory Committee. US Access Board, 15 November 2006. Government (US Access Board federal advisory committee of 35 members, among them the Hearing Loss Association of America, courts, architects, code bodies and disability groups) ↩︎ https://www.access-board.gov/ada/additional-resources/designing-accessible-courthouses.html
  11. IEC 61603-7:2003 Transmission systems of audio and/or video and related signals using infra-red radiation, Part 7: Digital audio signals for conference and similar applications. IEC Technical Committee 100 (Audio, video and multimedia systems and equipment). International Electrotechnical Commission (webstore abstract), 22 May 2003. Standards body (International Electrotechnical Commission; the full text is sold, the abstract is free) ↩︎ https://webstore.iec.ch/en/publication/5660

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