What is Auracast broadcast audio?
Auracast is the Bluetooth SIG name for broadcast audio in Bluetooth LE Audio. It is built on isochronous channels, which the Bluetooth SIG says were introduced in Bluetooth Core 5.2. There are two kinds:
- Connected isochronous streams are point to point, for example a phone to a pair of earbuds, with acknowledgement.
- Broadcast isochronous streams are one to many and sent without acknowledgement. The Bluetooth SIG says a broadcast can reach an unlimited number of receiving devices, and a broadcast group can carry up to 31 streams.
For events, that means a venue can send the room audio, a translation or a commentary track to every guest who has a compatible device. The Bluetooth SIG describes this as a bring-your-own-device model: listeners use their own earbuds, headphones, hearing aids or cochlear implants, so the venue does not hand out and collect dedicated receivers. Transmitters can be built into sound systems or run from a phone or tablet.
Early venue deployments listed by the Bluetooth SIG include performing arts venues, a university arts centre, churches, a theatre and a cathedral.
Does Auracast use the event WiFi or internet?
No. A broadcast runs directly from the transmitter to listeners over Bluetooth radio. It does not pass through the access points and does not use internet bandwidth. It still matters to the network plan in three ways:
- Shared radio band. Bluetooth LE radios work in the 2.4 GHz band, the same band used by 2.4 GHz WiFi, many wireless controllers and other short-range devices. In Australia, ACMA lists 2400 to 2483.5 MHz among the shared frequencies used by low interference potential devices, which operate under a class licence with no individual licence needed.
- Audio sources on the network. If the broadcast carries a remote presenter, an interpreter working off site or a streamed program, that audio arrives over the internet first. A dropped connection then becomes silence in every listener's ear.
- Joining through signs and phones. Guests often join a broadcast by scanning a QR code or using an app on their phone, which sits next to the WiFi details on your signs.
Our wireless microphones and spectrum article covers the other radio systems that share a stage with event WiFi.
How should event WiFi be planned around broadcast audio?
The aim is to leave 2.4 GHz as quiet as practical and keep any audio that depends on the internet on its own protected path.
| Planning item | What to do |
|---|---|
| Guest WiFi bands | Steer guests to 5 GHz and 6 GHz where devices support it. Limit 2.4 GHz to devices that need it, at lower transmit power. |
| 2.4 GHz channels | Use non-overlapping 20 MHz channels only, and fewer 2.4 GHz radios than 5 GHz radios in dense areas. |
| Access point capacity | Keep to about 50 active devices per access point and about 900 m² per access point in open areas. |
| Remote audio feeds | Put interpreters and remote presenters on a wired or dedicated link. A video call needs about 1.5 Mbps in both directions per site. |
| Backup path | Add a second internet path with automatic failover for any session where remote audio feeds the broadcast. |
A site survey before the event shows what else is already using 2.4 GHz in the venue, such as building systems or neighbouring tenants. For exhibitions, our guide to trade show WiFi interference explains why crowded halls need this check most.
How should multi-room events name and secure broadcasts?
Bluetooth SIG guidance for broadcast transmitters treats the broadcast name much like a WiFi network name, and it raises points that apply to conferences and venues with several rooms:
- Clear names. Name each broadcast after its room or language, for example Ballroom English or Room 2 Mandarin, so guests pick the right one from a list.
- Signals pass through walls. The guidance warns that people in neighbouring rooms may receive a broadcast, and recommends setting transmit power to the minimum that gives reliable coverage in the intended area.
- Encrypt private sessions. Public broadcasts often run unencrypted. Where content is confidential or personal, such as a board briefing or a members-only session, the guidance says encryption should be used. The broadcast code is 4 to 16 characters and can be shared on a printed card or a QR code.
- Separate languages. Language versions should go in their own subgroups, so a listener chooses English or a translated stream rather than hearing both.
- Low latency for live speech. For live events where listeners also hear the room, the guidance points to low-latency settings so that audio and lip movement stay in step.
- Limited streams per transmitter. Airtime limits how many streams one transmitter carries, so plan one transmitter per room or language group.
Our partner AV specialists can integrate transmitters at the sound desk, while the network plan keeps the feeds and the WiFi out of each other's way. See event lighting and sound.
Should venues replace hearing loops with Auracast?
Not yet. The Bluetooth SIG itself recommends adding broadcasts alongside existing systems, and notes that hearing loops still have a role. Many hearing aids in use today rely on a telecoil to pick up a loop, and not every guest has a phone, earbuds or hearing aids that support LE Audio broadcast.
Australian accessibility requirements also continue to refer to established hearing augmentation systems. A 2022 Australian Government consultation on hearing augmentation in public transport premises discussed induction loops reached through a hearing aid telecoil, with options such as covering at least 80 per cent of the area served by the public address system. It did not mention Bluetooth broadcast.
For event organisers, the practical approach is:
- Ask the venue what hearing augmentation is installed and which rooms it covers.
- Treat broadcast audio as an additional option for guests with compatible devices, not as the only one.
- Check any accessibility obligations for your event with the venue or a qualified access consultant. This article is general information, not legal or compliance advice.
What should organisers test before the event?
- Walk test. Join each broadcast with at least two different phones and earbuds, and walk the room edges and the corridor outside.
- Neighbouring rooms. Confirm a private session cannot be heard next door, or that it is encrypted.
- WiFi under load. Run the guest WiFi with a realistic number of devices while the broadcast is on, and check both for dropouts.
- Remote audio failover. Unplug the primary internet link during a test call and confirm the backup takes over before listeners notice. See backup internet.
- Signs. Put the broadcast names, any codes and the WiFi details on the same signs at the entry and in each room.
If you are planning a conference, faith service or performance with broadcast audio, send the floor plan, the room list and the audio plan through our contact page and we will suggest a network layout around them.
Questions people ask
What is Auracast?
Auracast is the Bluetooth SIG name for broadcast audio in Bluetooth LE Audio. One transmitter sends an audio stream that any number of nearby compatible earbuds, headphones and hearing aids can receive.
Does Auracast use the venue WiFi or internet?
No. The broadcast goes directly over Bluetooth radio. It shares the 2.4 GHz band with WiFi, and any remote audio it carries arrives over the internet first, so both still need planning.
Can people in the next room hear an Auracast broadcast?
They can. Bluetooth SIG guidance notes that broadcasts pass through walls and recommends the lowest transmit power that covers the intended area, plus encryption for confidential or personal content.
Does Auracast replace a hearing loop?
Not at this stage. The Bluetooth SIG recommends adding broadcasts alongside existing systems such as hearing loops, since many listeners still rely on a telecoil or do not have compatible devices.
How do guests join a broadcast?
Usually by choosing the broadcast name in a list on their phone or hearing aid app, or by scanning a QR code. Private broadcasts also need a code, which can be printed on a card.
Sources
- Bluetooth SIG: 10 frequently asked questions on LE isochronous channels
- Bluetooth SIG: How to design an Auracast transmitter (guidance document)
- Bluetooth SIG: Venues worldwide are already deploying Auracast systems (August 2025)
- Bluetooth SIG: How Bluetooth is creating a more accessible world
- ACMA: Low interference potential devices (LIPD) class licence
- ACMA: Wireless microphones
- Australian Government: Hearing augmentation in infrastructure and premises (Transport Standards consultation, 2022)
Event dates, prices and product details can change. Check the organiser or manufacturer before you plan around them. Planning figures are starting points; every network is confirmed against the actual site.