Planning Auracast assistive listening

Rules of thumb

• Plan for the full room. People absorb 2.4 GHz signal. An empty room always looks better than the event will.
• Mount high and central. Around 2.5 to 4 m, with a clear view over the audience’s heads.
• A solid wall means a new zone. Concrete, stone and brick block most of the signal; give the space behind them its own transmitter.
• One cell covers roughly 15 to 30 m. Larger rooms use several cells sharing one broadcast, overlapping by about 10 to 20%.
• Use the lowest power that works. Less spill into neighbouring rooms and less interference.
• Keep at least 2 m from Wi-Fi access points. Wi-Fi is the strongest interferer on most sites.

The three-check sign-off

A strong signal alone is not a pass: a signal meter cannot see packets colliding in a busy band. Sign off only when all three pass.

• Signal at target at the farthest seats, at ear height.
• A quiet band at the busiest hour, checked with a Wi-Fi analyzer or spectrum analyzer.
• A real listening test with the receivers people will use.

A good audio feed

Coverage gets the signal to every seat; the feed decides what people actually hear. Most installs add assistive listening to an existing system that routes analog audio, and the sound operator is watching the loudspeakers, not the assistive listening mix. So the feed has to look after itself.

• Use a dedicated output. A spare aux, matrix or DSP output that carries only the assistive listening mix, labelled and protected from scene recalls.
• Follow the main mix. Take it after the channel faders, so what the operator brings up or mutes is what listeners hear.
• Skip the loudspeaker processing. No room correction EQ, loudspeaker delay, crossovers or feedback suppression. They tune the room, not the headphones.
• Keep the level steady. Automatic gain control or gentle compression, so quiet and loud talkers arrive at the same level.
• Gate the open mics. Noise gates or an automixer keep unused microphones from adding room noise and echo.
• Include everything. Speech, music, playback, video audio and announcements.
• All-digital system? If there is nothing analog to tap, someone, usually the customer, must have the DSP programmer add a dedicated output. Agree who and when before installation day.

What the IT team needs

Networked transmitters need PoE+ ports, multicast with IGMP snooping for shared broadcasts, and a handful of management ports. BroadcastPlan generates the exact list for each design.

Standards and conformity

IEC 63087:2026 and the ISCVE Code of Practice already set out how an assistive listening system should be assessed and reported; IEC 60118-17, specifically for 2.4 GHz streaming systems, is still being written. See how BroadcastPlan Pro's standards readiness record maps onto each one →

Glossary

Auracast. Bluetooth LE Audio broadcast: one transmitter, any number of compatible receivers, phones and hearing aids.

dBm. Signal level. Closer to zero is stronger: −60 dBm is stronger than −75 dBm.

Cell. The area one transmitter serves well.

Master and extender. Transmitters that carry the same broadcast, so listeners move between cells without a gap.

Program. One audio feed, such as the main service, a second room or a translation.

AGC. Automatic gain control: evens out loud and quiet sources so listeners don’t have to keep adjusting the volume.

DSP. The digital signal processor that routes and processes audio in many modern sound systems. A new output usually means someone has to reprogram it.

Spill. Signal that reaches beyond the room, into spaces that should not hear it.

Listening area. A place where people listen, such as the seats or a standing area. Coverage is judged inside listening areas.

Broadcast Code. A password on an Auracast broadcast, so only people who have it can listen. Useful where neighbours must not hear.