Bluetooth might be revolutionising the audio world… again. Stuart Corner finds out what the latest innovation, Bluetooth Auracast, is and how it’ll impact our day-to-day lives.

Imagine being in an airport, waiting for your flight. Instead of having to listen to the cacophony of flight announcements while you stare at a TV screen trying to entertain you, silently, you can hear the TV sound through your Bluetooth earbuds, without the distraction of numerous announcements knowing that you will also hear when your flight is called.

Or, imagine working out at the gym, and instead of facing multiple silent screens and piped music, tuning into sound from one interesting video, or hearing your choice of workout-inspiring music.

Those are just two of the ways in which a new version of Bluetooth, Auracast, is set to change the way we experience audio in public places dramatically. The Bluetooth Special Interest Group (SIG) — the global body responsible for the Bluetooth standard — estimates that 60 million locations worldwide have the long-term potential to benefit from deploying Auracast broadcast audio.

And for people with hearing difficulties (whose ranks are growing as the population ages), Bluetooth Auracast promises to deliver better quality sound, a hearing experience in public spaces greatly superior to today’s telecoil technology and to greatly improve the overall experience of using hearing aids controlled via smartphone apps.

The Bluetooth SIG is talking up the potential of Auracast, big time.

It says Auracast will: “Enable us to fully enjoy television in public spaces, unmuting what was once silent and creating a more complete watching experience and it will allow us to hear our best in various public venues and environments.”

There are predictions that Auracast will become pervasive. The SIG quotes Chris Church, a senior staff engineer at Qualcomm Technologies suggesting that, if Auracast happens to become unable in a particular location: “You’ll quickly wonder where it has gone and how you managed to live without it for so long.”

So how does Auracast work? With today’s Bluetooth technology a receiver, such as wireless earbuds or a hearing aid, must be ‘paired’ with a Bluetooth transmitter, such as a smartphone, to receive a signal from that transmitter.

With Auracast, the Bluetooth transmitter transmits both its audio stream and a separate Bluetooth data stream identifying itself and details about the content of the Bluetooth data stream. An app on a Bluetooth Assistant, typically a smartphone, can display a list of all available Auracast data streams enabling the user to select one and instruct an Auracast receiver. For example, an earbud to connect to that data stream.

In a large venue such as an airport, Auracast transmitters would be dedicated, specialised devices, but a smartphone will also be able to act as an Auracast transmitter as well as an Auracast assistant, enabling a phone call or a song to be shared with other nearby users of Auracast capable devices such as earbuds.

The Auracast enhancement to Bluetooth was initially known as Audio Sharing. It’s part of the Bluetooth LE Audio specifications. LE (low energy) audio features were first incorporated in the Bluetooth 5.2 specification in 2019, but the full set was unveiled only in July 2022 and described by Bluetooth SIG chief executive Mark Powell as “the largest specification development project in the history of the Bluetooth SIG”.

LE Audio delivers improved audio quality and interoperability and reduced power consumption.

“One of LE Audio’s greatest achievements will be to open up the audio market to new entrants and make it easier to develop lower cost, lower complexity, non-proprietary products that have better synchronisation, lower latency, improved power consumption,” according to the Bluetooth SIG.

The introduction of Auracast LE Audio’s services in public places like airports, bars and gymnasiums will depend on the availability of technology and on the pace at which owners and operators of these venues choose to deploy it. However, LE Audio technology is likely to make an impact first in the hearing aid market, presently bedevilled by a lack of standards and by compatibility issues between hearing aids and the smartphones used to control and configure them.

It was, in fact, the limitations of the earlier Bluetooth technology, particularly for power-constrained devices like hearing aids, that precipitated the development of Bluetooth LE Audio and Auracast.

In 2014, the European Hearing Industry Manufacturers Association (EHIMA) joined the Bluetooth SIG to develop a new standard for hearing aids. The intention was to enable hearing device users to receive high-quality voice and media audio directly to these devices via Bluetooth and to ensure interoperability with any brand that used the technology.

Following these initial developments, the SIG says: “It soon became clear that developing a new audio standard could also bring significant benefits to the wider consumer audio market and address many of the limitations of Bluetooth Classic Audio.”

As a result, many of the enhancements in LE Audio will be of particular benefit to the millions of people with hearing difficulties who today rely on Bluetooth-powered hearing aids controlled and managed through smartphone apps. It will deliver much improved sound quality, better functionality and longer hearing aid battery life.

“The low energy audio feature of Bluetooth LE Audio will drive true global interoperability and standardisation and should deliver more selection choice and increase the overall accessibility for people with hearing loss,” Bluetooth SIG senior director for market development Chuck Sabin says.

Today Bluetooth hearing aid users suffer from multiple standards and compatibility issues. Hearing aid support for iPhones was made available under Apple’s Made for iPhone (MFI) program in the iPhone 4S (2010) and iOS 7 (2013). Google created the Audio Streaming for Hearing Aids (ASHA) open-source standard and incorporated it into Android 10 in 2019. It has since become available on most Android smartphones with Bluetooth 5.0 and higher. These different and incompatible technologies have limited customer choice and driven up prices.

Auracast support was added to Android in release 13, which came out in August 2022. Samsung announced in September 2023 that Auracast support would be available via a software upgrade for its Galaxy Buds2 Pro and Samsung 2023 Neo QLED 8K TV.

Apple appears to be dragging its heels. Although support for Bluetooth 5.3 was introduced with the iPhone 14, neither iPhones nor Apple AirPods wireless earbuds yet support LE Audio and Auracast.

As to the availability of hearing aids that will support Auracast and LE Audio, Jabra claims the Jabra Enhance Pro 20 to be “the industry first hearing aid to connect to Bluetooth LE Audio and Auracast” and it lists the Samsung Galaxy S23, S23 + and S23 Ultra as compatible phones with Auracast support (however, the Enhance Pro 20 aids will work with other Android phones that support ASHA).

The ReSound Nexia hearing aid is also claimed to have Auracast support but does not appear to be available in Australia. Auracast support is also a feature of the latest Cochlear hearing assistance implant, the Nucleus 8.

Deployment of Auracast in public venues will depend on the availability of transmitters and the incentives that will spur venues to deploy it. Taiwanese company Nexum claims to have the first Bluetooth transceiver with Auracast broadcast audio. MoerLink has a USB version with a range of up to 20m. However, these are products designed for personal use rather than public places.

Chipmaker RealMCU is offering processors that support LE Audio and Auracast and in December 2023 semiconductor manufacturer Telink used an Auracast transmitter based on its chipsets to demonstrate Auracast broadcast audio in an auditorium, an airport sports bar and an airport gate. A similar demonstration was staged in Sydney in December 2023 to coincide with a Bluetooth member summit and interoperability testing event in the city.

A major application of Auracast is expected to be the delivery of audio via hearing aids in public places. This is a somewhat contentious topic. Today the worldwide standard system is the telecoil: a wire running around a venue transmits a radio signal that is picked up by a small coil in the hearing aid. The system is not without its limitations: coverage can be patchy.

On the face of it, Auracast would seem to win hands down as an alternative: it will be compatible with all other aspects of hearing aid operation supported by Bluetooth and comprehensive coverage of a venue will be easy to establish, simply by locating transmitters appropriately.

However, in contrast to the very bullish predictions for Auracast coming from the Bluetooth community there is some scepticism in the hearing assistance industry. One audiologist claiming over 40 years’ experience, writing in August 2022, said: “Telecoils and hearing loops remain the best and simplest solution for the foreseeable future and consumers will need access to both telecoils and Auracast for many years to come.”

Needless to say, the Bluetooth SIG has a rather different view its market research report: LE Audio: The Future of Bluetooth Audio lists one of the top use cases for Auracast as: “A high-quality, lower cost augmented and assistive listening technology in venues where a public address or hearing loop infrastructure is currently deployed.”

It estimates that, by 2030, there will be close to one million such deployments worldwide, second only to its 1.1 million estimate for ‘silent’ TV screens in public places.

However, the report does concede that: “From a regulatory perspective, much work also needs to be done to incentivise Auracast broadcast audio as a primary assistive listening technology in various public venues or within new buildings as standard.”

To estimate the likely impact of Auracast, a little history might be useful. It is more than 25 years since Bluetooth (the name is that of a 10th century Danish king who envisioned a united Nordic peoples) was announced by Ericsson, IBM, Intel, Nokia and Toshiba. Today it’s ubiquitous and the functionality it offers is taken for granted. However, that 1998 announcement showed just how different the world was then, and the extent to which Bluetooth’s promise of ubiquitous wireless connectivity has been fulfilled.

That first press release said: “Bluetooth will eliminate the need for business travellers to purchase or carry numerous, often proprietary cables by allowing multiple devices to communicate with each other through a single port… Enabled devices will not need to remain within line-of-sight and can maintain an uninterrupted connection when in motion or even when placed in a pocket or briefcase.”

The potential of Auracast is yet to be realised, but I’d go with the prediction about Auracast and LE Audio from Chris Church of Qualcomm mentioned earlier: “In few years’ time, just as with Bluetooth, we will wonder how we ever managed to live without it.”