LE Audio and Auracast: The First Real Numbers
The replacement for classic Bluetooth audio is finally shipping on both ends. We measured what LC3 does to battery, latency and quality — and tried broadcasting to a room.
Tech Daily Review Desk
What changed
LE Audio is now in the phones, the earbuds and the hearing aids at once, which is the condition it needed. Auracast, the part that lets one source broadcast to any number of listeners, has started appearing in airports, cinemas and lecture halls.
LC3 is a more efficient codec, so it reaches the same perceived quality at roughly half the bitrate. Half the bitrate means less radio time, which means less power at both ends and more headroom when the band is busy. The broadcast part works because the stream is one-to-many with no pairing at all — a receiver joins it the way it tunes a radio station, which is also the reason it needs thinking about from a privacy point of view.
What is at stake
Because this is the first Bluetooth audio change in a decade that alters what the technology can do rather than how well it does the same thing. Sharing audio with a room, or with somebody else's hearing aids, is a different category of thing from a better codec.
Our method
Two pairs of earbuds supporting both stacks on the same phone, same programme, switched between classic and LE Audio. Battery was measured to a fixed cut-off rather than by the earbuds' own indicator. Latency was measured with a microphone against the source signal. The broadcast test used one transmitter and nine receivers in a 12-metre room, with a tenth receiver walking away from the source until it lost the stream.
What we recorded
| Measure | Classic (AAC) | LE Audio (LC3) | Auracast broadcast |
|---|---|---|---|
| Negotiated bitrate | 250 kbps | 128 kbps | 96 kbps |
| Playback time, same buds | 6 h 10 m | 8 h 45 m | 9 h 05 m |
| Phone battery, 4 h listening | 9% | 6% | 5% |
| Latency, audio to ear | 142 ms | 55 ms | 68 ms |
| Blind quality preference | 4 of 9 tracks | 5 of 9 tracks | not tested |
| Receivers before degradation | 1 | 2 | 9 with none |
| Range to dropout | 11 m | 14 m | 22 m |
What the data shows
The battery result is the headline: two and a half hours more from the same earbuds on the same programme, because the radio is working half as hard.
At half the bitrate our blind panel slightly preferred LC3, which is the point of a better codec and is still a strange sentence to write.
Latency fell from 142 ms to 55 ms, which takes Bluetooth from unusable for video to unremarkable for it.
Nine simultaneous receivers on a broadcast showed no degradation at all, and that is the capability classic Bluetooth simply does not have.
Caveats
Three things worth holding on to when you meet these figures somewhere else:
- "Bluetooth 5.3" on a box does not mean LE Audio, and LE Audio does not mean Auracast — three separate claims, routinely conflated
- Both ends have to support it, and a firmware update that enables it on the earbuds does not enable it on the phone
- An unencrypted broadcast can be joined by anybody in range, which is the intended behaviour in an airport and worth remembering everywhere else
What we would do
Do not replace working earbuds for this, but do check the box on your next pair — and check the phone, which is the end more likely to be missing it. The battery and latency figures are the real benefits for one listener, and they are substantial enough to be worth a tie-break between two otherwise similar products.
If anybody in your household wears hearing aids, this is the most useful thing in audio in years and worth seeking out deliberately. Broadcast audio from a television straight to hearing aids, with no pairing and no intermediate device, solves a problem that has had bad answers for decades. The same applies to anybody who has struggled with an airport announcement or a cinema.
Our verdict
Two and a half hours more playback, a third of the latency, slightly better sound at half the bitrate, and broadcasting to a room as a genuine new capability. The first Bluetooth audio change in years that is not just a number.
Behind this piece
Every product covered here was bought at retail and lived with for at least a fortnight before a word was written. Battery figures come from a scripted day rather than a manufacturer estimate, and sustained performance is measured warm — after half an hour of load — because that is the state a device spends most of its life in.
Where a firmware update changes a result, the piece is re-tested and the change noted rather than quietly corrected. No review unit arrives with conditions attached, and no score is agreed in advance with anybody.
Where to go next
If you are weighing this against the rest of the audio we have covered, the category archive lists every review in date order. The closest comparisons we have published are Matter and Thread, and Why Your Smart Home Still Is Not Simple (AirPods Pro 3) and Matter and Thread, and Why Your Smart Home Still Is Not Simple (Beyerdynamic DT 700 Pro X).
For the reference material behind these figures, the specification pages carry the measured numbers, and the common questions collect what people ask once something is in daily use.
