What is Bluetooth Auracast? How does Bluetooth Auracast work?

Bluetooth technology has come a long way since its launch in the 90s. Back then it was mainly used for wireless headphones and transferring files between devices. But Bluetooth has evolved much over the past few decades.

Today, Bluetooth powers everything from wireless speakers and keyboards to wearables and beacons. And now, there is a new product appearing - Bluetooth Auracast.

What is Bluetooth Auracast?

Bluetooth Auracast is part of the exciting audio capabilities of the Bluetooth LE Audio standard. With Auracast, a single audio source can stream to an unlimited number of listeners at once. This opens up all kinds of exciting wireless audio experiences.

Some key features and capabilities of Bluetooth Auracast include:

1. Audio sharing : You can share audio from your smartphone, tablet, PC, or other device with multiple listeners at the same time. Everyone can listen with headphones or earbuds, allowing you to enjoy music, video, or other audio together. No more gathering around a single speaker.
2. Public Broadcast : Auracast enables public audio broadcasting to anyone within range using a compatible receiver. For example, using headphones, you can adjust the sound from TVs in public spaces such as bars, airports, and gyms.
3. Hearing aids : Auracast can help people with hearing loss overcome background noise in public areas by streaming directly to their hearing aids or receivers. It can also provide multilingual broadcasts in locations such as theaters and convention centers.
4. Unlimited Listeners : There is no limit to the number of devices that can receive an Auracast audio stream, unlike traditional Bluetooth pairing, which is a one-to-one pairing. The only limit is the range of the transmitter.
5. CD-quality audio : Auracast can play audio in uncompressed CD quality instead of relying on lossy Bluetooth audio compression like SBC or AAC. This enables high-fidelity wireless audio.
6. Encrypted Broadcasts : Auracast streams can be encrypted with a password for private listening, so only intended listeners can tune in. Public broadcasts can be open to anyone nearby.
7. Low Latency : Bluetooth LE Audio significantly reduces latency compared to classic Bluetooth, making gaming, watching videos or monitoring live music much better.
8. Longer battery life : LE Audio is much more energy efficient, reducing power consumption for transmitter and receiver devices.
9. Get translations : Some places can stream multiple tracks using Auracast. So you can listen to real-time translations of announcements, videos, etc. with headphones, which is extremely convenient when traveling abroad.

 Auracast brings Bluetooth audio into a new era and opens up exciting new use cases.

How does Bluetooth Auracast work?

What is Bluetooth Auracast? How does Bluetooth Auracast work? Picture 1

At the core of Auracast is the ability for a single transmitter to broadcast audio to an unlimited number of receivers at the same time. This is done using Bluetooth LE Audio, part of the Bluetooth 5.2 specification.

With classic Bluetooth, audio transmission works on a one-to-one basis. The phone connects to the speaker, the headset connects to the phone, etc. But Auracast creates an audio "bubble" within which compatible receivers within range can pick up the broadcast.

The transmitter streams audio via Bluetooth LE in an uncompressed format, providing CD-quality wireless audio. It uses an advanced audio coding scheme called LC3plus, which delivers high fidelity while minimizing latency and power consumption.

The receiver will then scan for available Auracast streams. Streams can be opened for anyone to access or encrypted with a password for private listening. When the receiver detects and finds the stream, it decodes the audio in real time and plays it through headphones or speakers.

All of this happens seamlessly without having to manually pair each listener. From the user's perspective, it's as simple as pressing Play on the player and putting on the headphones. The headphones will automatically sync and start receiving broadcasts.

Multiple Auracast streams can exist in the same region on different "channels" without impact. Listeners simply tune in to whatever stream they want. The range of a transmitter largely depends on the type of broadcast power it has. Lower power offers shorter transmission ranges of over 9m, while higher power models can transmit up to ~275m.

 The main advantage of Auracast is that it is bidirectional. Information flows in both directions between the transmitter and receiver. This enables useful features:

1. Volume control : The receiver can control the volume independently of the source.
2. Track information : Song titles and other data appear on the receiver.
3. Group mute : The transmitter can remotely mute all receivers at the same time.

For private listening, Auracast streams can be encrypted with a 128-bit key via AES encryption, just like what Bluetooth Classic uses. This prevents unauthorized listening of unencrypted public streams.

In summary, the two main components that enable Auracast are the LC3plus audio codec and the broadcast audio profile in the Bluetooth LE protocol stack. These enable high-quality, low-latency multi-listener streaming.

Which devices run Auracast Bluetooth?

Any device equipped with a LE Audio Bluetooth radio and integrated with the appropriate software can transmit or receive Auracast broadcasts. As of the time of writing, Auracast device support is still limited but growing rapidly.

Transmitter:

1. Samsung TVs : Neo QLED 8K, microLED TV 2023 - enabled via software update.
2. Tablet : Samsung Galaxy Tab S8
3. Smartphone : Samsung Galaxy S23, Google Pixel 7, Samsung Galaxy Z Fold 4, OnePlus 10T
4. Laptop : Dell XPS 13 Plus

Receiving device:

1. Earfun Air Pro 3
2. OnePlus Buds Pro 2
3. Technics EAH-AZ60
4. Samsung Galaxy Buds 2 Pro
5. 1More ComfoBuds Mini
6. Hearing aids (VOCE by Nexum)
7. Bluetooth 5.2 speaker or headset with Auracast support

While the number of options is still small, we're on track to see a huge explosion in Auracast-compatible devices. Any product with Bluetooth 5.2 can support it with the appropriate software update. By default, all upcoming devices with Bluetooth 5.3 or higher will include LE Audio/Auracast.

So if you're looking to buy Auracast-ready products now, focus on these key features:

Transmitter:

1. Bluetooth 5.2/5.3
2. LE audio support

Receiving device:

1. Bluetooth 5.2/5.3
2. LE audio support
3. The specific device mentions Auracast support

Expect more devices to support Auracast in the very near future.

Kareem Winters

Update 13 October 2023