Assistive Listening Knowledge Base
  • Industry code of practice

Code of Practice for the Design and Operation of Assistive Listening Systems, Issue 1

From https://assistivelisteningknowledgebase.org/evidence/iscve-cop/ · record checked 13 October 2026

  • Audio Industries Committee on Assistive Listening Systems
  • Audio Industries Committee on Assistive Listening Systems; distributed by the Institute of Sound, Communications and Visual Engineers (UK)

Trade body (Audio Industries Committee on Assistive Listening Systems, an audio industry committee; distributed by the Institute of Sound, Communications and Visual Engineers; the code names no funder)

Summary

A UK code of practice for assistive listening, with a list of measurements for Auracast systems.

Key findings

  • Clause 7.1 (page 17) says a minimum provision of venue receivers is still needed because listeners cannot be expected both to bring a working compatible hearing device and to know how to connect and use it.
  • Clause 7.2.2(iv) (page 18) encourages witness testing with hearing-loss users and their own compatible devices where practical, with feedback documented. Clause 11.3 (page 37) says it is useful to obtain the views of a hearing aid user or hard-of-hearing listener because perceived intelligibility may differ from that of listeners with normal hearing or mild hearing loss.
  • Clause 11.1 (page 36) calls for measurements at normal receiver heights and positions, considering the effects of full occupancy. Separate receivers should be tested in their intended positions, such as a pocket, belt clip or lanyard, for seated or standing use as appropriate. Clause 11.2 asks for coverage checks throughout the area and test positions marked on a room plan.
  • Clause 10 (page 35) applies its handover guidance to any assistive listening system; the operation and maintenance manual includes equipment handbooks and system operating instructions alongside drawings, coverage maps, commissioning reports and commissioned settings.
  • Clause 7.8 explains that faults can go unnoticed until a person with hearing loss uses the system. Its minimum routine check uses a listening device and a normal-use source, including speech at the normal microphone distance, with a tester able to judge the received level and quality. It recommends checks during events because the audience and its activity can alter RF and optical signal levels (page 28).
  • Clause 7.8 recommends listening through a test device with a source representative of normal use, using a tester familiar with the correctly operating system. Checks should be at least as frequent as other audio-system checks, at intervals no longer than monthly, weekly for regular use, before each event and regularly during events (pages 28-29).
  • Clause 7.8 asks for routine results in a system logbook, review of status-monitoring records, repeat performance tests appropriate to the technology, and fault or power-loss alerts where active monitoring is possible. It calls for checks after relevant building work, room reconfiguration, sound-system changes or operation by a third party, and benchmark testing when a new maintenance organisation takes over (pages 28-29).
  • Clause 10 calls for a documented complaints process, communicated to customer-facing staff and advertised to hearing-device users, designed for prompt resolution (page 35). Clause 11.3 says hearing aid users and hard-of-hearing listeners may perceive intelligibility differently from listeners with normal hearing (page 37).
  • Clause 11.3 checks the received speech first with a recording and then with a source representative of normal use, such as a talker at the system microphone speaking at a normal level, position and distance. Listening checks assess intelligibility, frequency balance, noise and distortion; problems call for objective tests to establish the cause (page 37).
  • Clause 4.15 defines competence through relevant current training and experience, access to the necessary tools, equipment and information, and ability to perform the task. Informative Annex F lists ISCVE as an organisation for assessing competence.
  • Clause 11 recommends that the installer or system specifier carry out performance tests after installation, including subjective and objective appraisals. Clause 11 allows some simple one-to-one systems to be assessed subjectively, depending on the technology and installation, with objective measurements if there is uncertainty. It requires a test report for venue management and does not require a separate external assessor for every installation (pages 35-36).
  • Clause 10 calls for operator training at handover, an operation and maintenance manual with as-fitted drawings, coverage maps, commissioning reports and equipment settings, and an opportunity for the operator to hear a demonstration. At least one venue representative should be trained and equipped to perform routine tests, and customer-facing staff should receive refresher training.
  • Annex A.3 (informative) lists the measurements that should normally be made on Auracast systems: frequency response, audio signal level, signal-to-noise ratio, coverage (signal strength and packet loss), latency, network performance, interference from other RF transmissions and a subjective assessment; STI is optional.
  • Clause 11 asks for a "certificate of compliance" after testing, and for measurements at the normal listening height (1.2 m seated, 1.7 m standing for systems that transmit to hearing aids), taking account of a fully occupied space.
  • Clause 9.8 recommends that the time difference between audible speech in the assistive listening signal and the acoustic sound, at similar sound levels, be 30 ms or less where possible, with 40 ms the limit of acceptability, counting the whole signal chain. With a video display of the talker, audio-to-picture timing should preferably be under 40 ms and no more than 50 ms.
  • In large venues, the stream may need to be delayed, or split into zones with different delays, to align with the acoustic sound.
  • The delay discussion in clause 9.8 (pp. 34-35) applies its 30 ms preference and 40 ms limit to audible speech signals of similar level. It notes that percussive music may require a shorter delay, and that a level difference of even a few dB can reduce the perceived discrepancy.
  • Clause 11.3 (page 37) recommends checking audible delay or echo between received assistive sound and room sound using live speech, and checking timing against live mouth movements or video; an apparent timing discrepancy calls for objective latency measurement.

Limits

A UK industry code, not an international standard. Written when Auracast was "not yet fully defined" and no systems were installed; Annex A is informative.

Read the original

iscve.org.uk/standards/assistive-listening-guide-and-code-of-practice

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Cited in

Cite this source

Audio Industries Committee on Assistive Listening Systems. Code of Practice for the Design and Operation of Assistive Listening Systems, Issue 1. Audio Industries Committee on Assistive Listening Systems; distributed by the Institute of Sound, Communications and Visual Engineers (UK). December 2023. https://iscve.org.uk/standards/assistive-listening-guide-and-code-of-practice/ (accessed 13 October 2026).

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