Auracast Broadcast Audio: One audio source transmits to any number of receivers
Auracast is a technology developed by the Bluetooth Special Interest Group (SIG) as part of the Bluetooth LE audio standard. This feature expands the possibilities of audio transmission via Bluetooth with the ability to send audio content from a single source to an unlimited number of receivers simultaneously. In practice, this can be thought of as a kind of Wi-Fi hotspot.
Until now, Bluetooth – the way we have been using it – has always provided a one-to-one connection between two devices. Auracast Broadcast Audio extends this, making it possible to send audio from one device to several receivers at the same time. This is achieved by using advanced audio transmission protocols as part of the Bluetooth LE audio standard.
Auracast Broadcast Audio can be used in different ways:
- Public areas: in airports or train stations, announcements can be transmitted directly to the headphones of the travellers involved. In museums, on guided city tours or even at concerts and clubs (keyword: “silent discos”), other areas of application are also conceivable: Only specific audio content is played in certain rooms.
- Teaching institutions: Lecturers can use Auracast to send customised educational content to students’ headphones.
- Accessibility: Auracast can be used to provide audio descriptions for the visually impaired. Another important aspect would be the possible integration with hearing aids. Hearing aids or cochlear implants can benefit from Auracast without relying on T-coils (telecoil or induction coil). Auracast could complement or even replace this technology by enabling direct and clear audio transmission to the corresponding hearing aids.
The technology behind Auracast Broadcast Audio
The great thing is that devices that support at least Bluetooth version 5.2 can already use Auracast. However, the relevant manufacturers would first have to activate this in the software. This is why, at the time of writing, there are not yet many headphones on the market that can handle Auracast. For example, the Samsung Galaxy Buds2 Pro (test) and the Sennheiser Momentum True Wireless 4 support this transmission technology. Some TVs have now also been equipped with it.
In terms of range, theoretically up to 400 metres and latencies of approx. 20 to 40 milliseconds should be possible. The new LC 3 codec (Low Complexity Communication Codec) is used here (see also our guide to Bluetooth codecs). The Bluetooth SIG has also given some thought to data protection: both encrypted (e.g. for home use) and unencrypted (e.g. at airports) streams are possible.
