In Auracast, a broadcast is one audio stream that a transmitter sends out and advertises by name, for any number of nearby receivers to join without pairing. The word is doing precise work here: it is the same idea as a radio station — one signal, many tuned-in listeners — and it is what separates Auracast from every connect-two-devices Bluetooth habit.
Protocol details on this page follow the Bluetooth SIG’s public documentation.
The word, precisely
"Broadcast" is the operative word in Auracast, and it is not decorating the name — it is the specification. A broadcast is one audio stream that a transmitter sends out and advertises by name, which any number of nearby receivers can join without pairing. The Bluetooth SIG’s FAQ makes the scale explicit: "An unlimited number of in-range Auracast™ receivers can join a single Auracast™ broadcast, in much the same way a standard radio transmitter sends out one signal that any number of in-range radio receivers can tune in to."
Radio is the right comparison, and the SIG’s FAQ reaches for it three times. A radio station transmits once; every listener within range tunes in for free; the hundredth radio costs the station nothing. Auracast imports that model into Bluetooth: the venue or the phone transmits once, and every hearing aid, earbud and phone in range can tune in the same way.
The word also draws a boundary against the older Bluetooth habit. Pairing links two devices and only two; a broadcast is joined by selection, from a list, with no pairing step. The how-it-works page walks that four-step flow; this page stays on the word itself.
The three parts of a broadcast
A broadcast has three moving parts, and they divide cleanly.
The stream — the audio itself, encoded over LE Audio with LC3, transmitted once. The advertisement — the announcement that carries the "broadcast name, contents, configuration..." and more, which is what assistants sweep for and display as the pick list. The audience — unlimited receivers, with the design deliberately placing the power-hungry scanning task on assistants (phones, watches, remotes) rather than on small-battery devices like earbuds and hearing aids.
The advertisement is the part the scan list is built from, and it deserves special attention for that reason: the name a venue chooses is the menu text every listener sees. "Gate A16" needs no explanation; a generic stream name turns the join into a guess. The name travels inside the advertisement, so naming well is naming once.
Open and locked
Every broadcast is one of two kinds. An open broadcast plays for any compatible receiver that selects it — the default for venue audio meant for everyone. A locked broadcast is encrypted, and the announcement says so: the white paper’s wording is that the announcement provides "Whether the stream is encrypted, in which case the user needs to obtain a Broadcast_Code." Hosts deliver that code their own way — printed on a ticket, encoded in a posted QR — and until a device has it, an encrypted stream stays silent.
That is the entire privacy model, and it maps cleanly onto real venues: the sanctuary stream open to the congregation, the press-feed locked to its credential holders. The what-is page places the profile in the LE Audio stack, and the Samsung guide shows the phone-side version of the same lock.
An Auracast broadcast is always "a broadcast" — singular, countable, hosted. Somebody transmits it, names it, and decides whether it is open. That grammar is the fastest way to explain the feature to anyone: not a mode you switch on, but a stream someone is putting out, with a name, waiting to be picked.
FAQ
One audio stream that a transmitter sends out and advertises by name, which any number of nearby receivers can join without pairing. The Bluetooth SIG compares it to a radio station: one signal, many tuned-in listeners. The broadcast is the stream plus its advertisement — name, contents and configuration.
The SIG states an unlimited number of in-range receivers can join a single Auracast broadcast, in much the same way receivers tune in a standard radio transmitter's signal. More listeners do not use more transmitter bandwidth, because everyone hears the same stream.
No — and the difference is the point. Pairing links two devices; a broadcast is joined by selection, with no pairing step. The SIG's assistant white paper also notes that the power-hungry scanning task is deliberately taken away from small devices like earbuds and hearing aids and given to assistants such as phones.
Yes. A transmitter can encrypt the stream, and the announcement then indicates that a Broadcast_Code is needed. The host delivers the code however it likes — a posted QR code, a printed password — and only devices with the code can play the audio.
blafili Bicast XLR Transmitter
XLR and USB-C inputs with Bluetooth 5.2 and a broadcast mode for feeding several receivers at once. Built for studios, venues and shared listening.
- Bluetooth SIG, Auracast FAQ: "An unlimited number of in-range Auracast™ receivers can join a single Auracast™ broadcast, in much the same way a standard radio transmitter sends out one signal that any number of in-range radio receivers can tune in to."; assistant-UI join flow. bluetooth.com/auracast/faq/, accessed 2026-09-24
- Bluetooth SIG, "How to build an Auracast assistant" white paper: advertisements carry "broadcast name, contents, configuration..."; the Public Broadcast Announcement indicates "Whether the stream is encrypted, in which case the user needs to obtain a Broadcast_Code"; scanning taken away from earbuds and hearing aids (small batteries). bluetooth.com, accessed 2026-09-24
- Bluetooth SIG, Auracast overview: "shared from a single transmitter to unlimited devices—without pairing." bluetooth.com/auracast/, accessed 2026-09-24
- Bluetooth SIG, Public Broadcast Profile 1.0 — encrypted broadcasts and Broadcast_Code. bluetooth.com/specifications/, accessed 2026-09-24