Summary
The SIG's recommendations for designing, installing and documenting simple standalone Auracast transmitters.
Key findings
- Section 1.2.1.2 (page 5) says High Quality stream support is not mandatory in BAP or PBP, so some Auracast receivers cannot receive and render those streams.
- A public Auracast transmitter must always transmit at least one Standard Quality stream, and products marketed for public locations must default to Standard Quality.
- Its example settings use a Presentation Delay of 40 ms, which it says all Auracast devices support; a flag can tell receivers they may render earlier.
- Transmitters should run at a long-term reference level of -35 dBFS (equivalent to 70 dB SPL) with a maximum of -3 dBFS.
- Recommends the lowest power that covers the intended area, found by walking the area with a receiver and raising power step by step, and repeating the check when the room is in use; mounting above head level reduces the effect of people.
- Section 3.2 (page 25), under Broadcast range, also asks installers to repeat the coverage check after the transmitter location changes, testing audio reception throughout the intended area.
- Encourages registering a public installation with the SIG.
- Says a transmitter can be designed to meet regulations worldwide at output powers up to +20 dBm, and that regulatory requirements differ between markets.
- Section 1.2.1.1 defines Standard Quality as the mandatory Broadcast Sink LC3 configurations at 16 or 24 kHz with 10 ms frames. Section 2.2 (pages 7-8) says public locations must make Standard Quality available for all audio content they provide through Auracast; the Broadcast quality guidance on page 25 repeats this for locations promoting Auracast availability.
- Section 1.2.1.2 identifies High Quality public broadcast audio with 48 kHz LC3 sampling; section 1.2.1.1 identifies Standard Quality with 16 or 24 kHz LC3 sampling.
- Section 2 (page 7) describes a standalone transmitter connected by cable to the output of a sound system or television; Figure 2.1 shows optical, HDMI ARC and analogue audio input examples.
Limits
Mostly recommendations; its mandatory statements come from the Auracast trademark requirements. It sets no numeric coverage or signal-strength pass/fail level.
Read the original
www.bluetooth.com/wp-content/uploads/2022/10/Auracast-Transmitter_Recommendations.pdf
Cited in
- How far does one transmitter really reach in a full room?Partly answered
- Which hearing devices can receive which systems?Open
- What signal strength is enough at the farthest seat?Open
- What audio level should the stream carry: -35 dBFS or louder?Disputed
- How much do crowds, phones and Wi-Fi reduce reliability?Open
- What commissioning tests and pass limits will the standards require?Open
- Can one venue offer several Auracast streams at once (languages, audio description, a mix for hearing aids), and how do listeners choose?Partly answered
- What does Auracast qualification and the Auracast logo cover, and what does it leave out?Partly answered
- How much do room acoustics and distance limit listening without a system, and what follows for choosing one?Partly answered
- How good is the sound each system delivers: bandwidth, codecs and speech understanding?Partly answered
- What should a venue specify and ask for when it buys an assistive listening system?Partly answered
Cite this source
Bluetooth SIG. Auracast simple transmitter best practices guide, version 3. 17 October 2025. https://www.bluetooth.com/wp-content/uploads/2022/10/Auracast-Transmitter_Recommendations.pdf (accessed 13 October 2026).
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