What signal strength is enough at the farthest seat?

Why it matters

Coverage tests need a stated method and pass mark: the SIG recommends a walk test without a numeric signal threshold, while one maker gives a range tied to its own receiver and signal level^1,2.

What the evidence shows

• No common numeric pass mark established here. The Bluetooth SIG recommends setting power by a walk test, repeated with the room occupied, without a pass/fail level¹. The UK code of practice lists signal strength and packet loss as coverage tests³. IEC 60118-17 will include a coverage measurement method⁴; IEC 63087:2026 includes coverage in its assessment report, but only its preview was read, so any numeric requirements in the paid text remain unchecked⁵.
• Makers use their own references. One maker states its 30 to 40 m coverage to -70 dBm on its own receiver²; its commissioning guide asks for an empty-venue reading "better than 60dB", with no sign or reference level, and does not publish the thresholds behind its pass marks⁶.
• Frame loss matters as well as signal level. An independent Ghent/imec simulation using 20 speech recordings, funded by imec and Flanders Innovation & Entrepreneurship and with a Cochlear co-author, found that interference causes lost audio frames and that more advanced packet loss concealment tolerates more frame loss⁷. One maker's guide treats poor quality despite a high signal reading as a sign of interference, for example from Wi-Fi⁶. A related Ghent/imec laboratory study, funded by imec and Flanders Innovation & Entrepreneurship and with a Cochlear Technology Centre co-author, uses about 2% frame loss as a general boundary below which almost none of the predicted quality scores fell into its lowest category, based on earlier analysis of 20 speech recordings. Its two-recording testbed study used an instrumental measure, without listeners; one recording had almost no scores in that lowest category even at about 5% loss⁸.
• The edge is steep. On that study's cabled testbed of two nRF5340 boards, mean frame loss without repeated transmissions rose from about 6% to about 22% over a 1 dB increase in attenuation, while four transmissions per frame held it at or below 0.4%⁸.
• Receivers differ. In Pro Audito's independent hall test of 53 rated pairs, with devices lent free by manufacturers, the same transmitter produced flawless reception on one receiver and severe dropouts on another⁹. Hearing aids and earbuds may receive less well than a phone, so a broadcast can appear in an app's list while being out of reach of the listener's own devices¹⁰.

Where sources disagree

One maker publishes its own acceptance level, tied to its own receiver, and does not publish the thresholds behind its pass marks^2,6; the sources reviewed do not establish a common reference receiver and pass mark. The numeric requirements of IEC 63087:2026 could not be checked from its public preview⁵.

What would settle it

A standard coverage measurement method, which IEC 60118-17 is to specify⁴, and published thresholds linking signal level and packet loss to listening results.

Planning while it is open

• Measure both signal strength and audio continuity (dropouts or packet loss) at the farthest seats^3,7.
• Repeat the walk test with the room occupied^1,6.
• Check reception with hearing aids or earbuds as well as with a phone or survey receiver, since they may receive less well¹⁰.
• Record the receiver used, because another receiver may give a different result⁹.

Sources

1. Auracast simple transmitter best practices guide, version 3. Bluetooth SIG, 17 October 2025. Standards body (Bluetooth SIG, an industry association funded by its member companies, which owns the Auracast trademark) ↩︎ https://www.bluetooth.com/wp-content/uploads/2022/10/Auracast-Transmitter_Recommendations.pdf
2. Auri coverage and install guide (application note UP3B609-01, rest-of-world edition). Listen Technologies and Ampetronic (Auri). Ampetronic, 17 April 2025. Manufacturer (Listen Technologies and Ampetronic) ↩︎ https://www.ampetronic.com/wp-content/uploads/UP3B609-01_RoW_Auri-Coverage-and-Install-Guide.pdf
3. Code of Practice for the Design and Operation of Assistive Listening Systems, Issue 1. 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), December 2023. 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) ↩︎ https://iscve.org.uk/standards/assistive-listening-guide-and-code-of-practice/
4. IEC 60118-17 (in preparation): assistive listening system for hearing aid users based on 2.4 GHz audio streaming. IEC TC 29 WG 13. International Electrotechnical Commission, undated (read 13 October 2026). Standards body (International Electrotechnical Commission) ↩︎ https://tc29.iec.ch/tc-activity/standards-under-preparation/
5. IEC 63087:2026 Assistive listening devices and systems for active assisted living. IEC TC 100. International Electrotechnical Commission, 18 September 2026. Standards body (International Electrotechnical Commission; the full text is sold, and only a preview is public) ↩︎ https://webstore.iec.ch/en/publication/95094
6. Auri user guide: RX1 commissioning tools (UP3B613-1). Listen Technologies and Ampetronic (Auri). Ampetronic, 2025. Manufacturer (Listen Technologies and Ampetronic) ↩︎ https://www.ampetronic.com/wp-content/uploads/UP3B613-01-Auri-User-Guide-RX1-Commissioning-Tool_A4_WEB.pdf
7. Evaluation of BLE-based audio broadcasting under probabilistic interference. Baert M, Moons B, Pittevils J, Song Y, Madhu N, Hoebeke J. Computer Communications 222:130-140, June 2024. Independent (Ghent University and imec; funding from imec and Flanders Innovation & Entrepreneurship; co-author Jowan Pittevils is affiliated with manufacturer Cochlear) ↩︎ https://www.sciencedirect.com/science/article/abs/pii/S0140366424001634
8. Experimental validation of a Bluetooth-based speech audio broadcasting model. Baert M, Pittevils J, Moons B, Hoebeke J. IEEE PIMRC 2024 (imec-IDLab, Ghent University; Cochlear Technology Centre), 2 September 2024. Independent (Ghent University and imec; imec.icon BLE2AV project financed by imec and Flanders Innovation & Entrepreneurship; one co-author from Cochlear Technology Centre) ↩︎ https://doi.org/10.1109/PIMRC59610.2024.10817355
9. Auracast transmitter-receiver compatibility test (with data workbook). Pro Audito Schweiz, 6 October 2025. Independent (Pro Audito Schweiz, Swiss hearing-loss association; no manufacturer funding, test products lent free by manufacturers) ↩︎ https://pro-audito.ch/news/auracast-transmitter-receiver-compatibility-test/
10. How to build an Auracast assistant: technical overview, version 1.0. Bluetooth SIG Market Development. Bluetooth SIG, 29 October 2025. Standards body (Bluetooth SIG, an industry association funded by its member companies, which owns the Auracast trademark) ↩︎ https://www.bluetooth.com/wp-content/uploads/2024/05/2403_How_To_Auracast_Assistant.pdf

Change log

• 10 October 2026Published with 10 sources.
• 13 October 2026Limited the signal-threshold claim to public evidence and clarified laboratory test limits.
• 13 October 2026Corrected the hall-test pair count, added affiliations and recording counts, and clarified predicted quality and mean frame loss.

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