Auracast: Revolutionizing Accessibility in Audio

By Megan Quilter, Au.D

Bluetooth Low Energy Audio (LE Audio) and its associated features represent an advanced wireless audio technology, designed to deliver high-quality sound with minimal power consumption to all users.¹ In contrast to standard Bluetooth, which can be power-hungry and limited in functionality, Bluetooth LE Audio offers more efficient, faster, and clearer audio transmission. This is particularly crucial for hearing aids, where both battery life and sound quality are paramount. By incorporating Bluetooth LE Audio, hearing aids can stream audio directly from various devices—such as smartphones, TVs, and public broadcasting systems—with lower battery drain. This technology enhances both usability and convenience, introducing a line of new features and making it revolutionary in the hearing care industry.

One of the most promising advancements within Bluetooth LE Audio is Auracast™ broadcast. This innovative feature allows audio to be streamed wirelessly from a single source to unlimited Bluetooth-enabled devices, including hearing aids and cochlear implants. Auracast broadcast enables individuals with hearing loss to connect directly to public audio systems in venues like theaters, airports, and lecture halls, ensuring they receive clear, personalized sound without needing additional equipment.² This technology not only improves accessibility for those with hearing loss but also enhances the listening experience for everyone, marking a significant step forward in inclusive audio technology.

Accessibility remains a critical challenge for individuals with hearing loss, as traditional audio solutions often fail to deliver consistent, clear sound in various environments. This challenge affects not only those with hearing difficulties but also individuals with normal hearing, particularly in noisy or large venues. The European Hearing Instrument Manufacturers Association (EHIMA) addressed these challenges with the Bluetooth Special Interest Group (SIG) by proposing the need for a new codec with lower latency, a dedicated hearing aid profile, and to include a broadcasting mode.³ Bluetooth Auracast broadcast emerged as a transformative response to this proposal, offering a universal, high-quality audio experience that caters to anyone using a compatible audio streaming device which will include wireless headphones, speakers, and earbuds, as well as hearing aids and cochlear implants. By enabling direct, personalized audio streams to Bluetooth-enabled devices, Auracast broadcast ensures that everyone can access sound with clarity and ease.

Bluetooth LE Audio address’ current limitations with a universal protocol. Major industry players like Samsung, Microsoft, and Google have also recognized the value of this innovation and its potential to elevate and transform communication for users of hearing aids, earbuds, headphones, cochlear implants, and other electronic devices. Auracast broadcast is set to become a leading standard in broadcast audio technology, offering improved experiences for users globally.^{4,5, 6}

The adoption of Auracast-enabled devices is expected to accelerate rapidly, with widespread deployments anticipated in public venues like transportation hubs, theaters, and sports arenas. By 2027, the number of Bluetooth LE Audio-enabled devices will reach billions globally. This significant growth in compatible devices will likely drive Auracast transmitters’ installation in nearly 2.5 million public locations worldwide by 2030. These advancements will greatly enhance broadcast audio accessibility, particularly for individuals with hearing loss, while also creating scalable solutions for assistive listening, opening new business opportunities and revenue streams for manufacturers and service providers.^5,6

Technical Overview

Auracast broadcast leverages Bluetooth LE Audio to simultaneously deliver high-quality, low-latency audio streams to multiple devices. Bluetooth LE Audio and Auracast was introduced as part of the Bluetooth 5.2 specification. At the core of Bluetooth LE Audio is the Low Complexity Communications Codec (LC3). An audio codec (short for “compressor-decompressor”) is a digital signal processing technology responsible for encoding and decoding digital audio data. It compresses audio files for storage or transmission and then decompresses them for playback. Previously, Bluetooth utilized the Sub-band Codec (SBC) to handle audio transmission. While the SBC can deliver decent audio quality, it struggles to maintain high fidelity at lower bitrates, leading to noticeable audio degradation. Additionally, SBC has an increased latency, which can be problematic in scenarios where real-time audio synchronization is critical, such as in video conferencing or live broadcasts.⁷

The LC3 codec is essential for enhancing both sound quality and file size. It surpasses the older SBC technology by providing superior audio quality and greater efficiency, which translates to reduced power consumption and clearer, crisper sound. The capability of LC3 to deliver high-quality audio at lower bitrates represents a major development, allowing for more efficient bandwidth usage and extended battery life while maintaining an excellent user experience.^7,8

In 2023, Bluetooth released a technical report titled “Performance Characterization of the Low Complexity Communication Codec.⁹ This white paper summarizes the results of listening tests conducted during the standardization of the LC3 codec, comparing it to older Bluetooth codecs—Sub Band Codec (SBC) and modified Sub Band Codec (mSBC). (Figure 1) The report demonstrates that LC3 significantly outperforms SBC regarding audio quality, offering clearer, crisper sound that enhances the overall user experience.

The study participants were “trained listeners,” and the results indicate that individuals with normal hearing can perceive the improved audio quality of LC3. Although the study did not include individuals with hearing loss, these findings suggest that LC3 can enhance the listening experience for those who can discern these differences. Even for users who might not notice a significant difference in audio quality, LC3 still provides important advantages, such as improved efficiency, reduced power consumption, and high-quality- particularly significant benefits in hearing aids.

This study underscores the dual advantage of LC3: it enhances the listening experience for those who can perceive it while delivering broader technological improvements that benefit all users, making Auracast a versatile and forward-thinking solution for assistive listening environments.

Until now, Bluetooth technology has been limited to transmitting audio to only one device simultaneously. In contrast, Auracast broadcast enables a single audio source to stream simultaneously to unlimited receiving devices. This capability transforms public spaces like theaters, lecture halls, and transportation hubs by allowing users to access broadcasts via their own devices, including hearing aids and earbuds. Auracast manages multiple synchronized audio streams with minimal latency, ensuring a seamless real-time audio experience for all users without perceptible delay.^7,10

To effectively operate Auracast, both a transmitter and a receiver are required, as well as an Auracast Assistant. The transmitter, which serves as the audio source, can be integrated into various systems such as public address systems, computers, televisions, hearing aid accessories, or any signal of interest that supports Bluetooth LE Audio technology. This transmitter continuously broadcasts the audio signal using Bluetooth LE Audio capabilities, making it available for any compatible receiver within range. Once an Auracast broadcast is detected, it is displayed as an available audio stream on the user’s device. For instance, in a theater, a person might see the option to connect to the main audio feed of the performance, while in a transportation hub, multiple broadcast streams for different announcements may be available. A list of broadcasts is then displayed, allowing the user to select the desired stream easily. Devices equipped with Bluetooth LE Audio technology and Auracast can detect and select the desired broadcast. Users can select which audio stream they want to receive at any given moment: a public announcement, live commentary at a sports event, background music in a public space, or audio from a television in a home environment. This connection process is designed to be quick and seamless, eliminating the need for the traditional pairing process that Bluetooth users are accustomed to. Once the stream is selected, the device’s codec activates to decode the compressed audio data, converting it back to its original, uncompressed form, allowing the device to reproduce the sound for the end user to experience accurately.^10,11

To effectively use Auracast technology, an Auracast Assistant will typically be needed to help users find and select the available audio broadcasts.¹¹ The Auracast Assistant is an interface that appears on the user’s device, such as a smartphone, smartwatch, computer, or tablet, and is similar to that of a Wi-Fi access point. This assistant becomes particularly important in environments with multiple broadcast options, such as a busy airport, a concert hall, or a sports stadium. When a user is within range of Auracast broadcasts, the Auracast Assistant can automatically scan for available audio streams. The assistant then presents a list of streams to the user, allowing them to easily select the broadcast they wish to hear. The Auracast Assistant simplifies the process of connecting to the desired audio source, ensuring that users can quickly and conveniently access high-quality, synchronized sound without needing to manually search for or pair with specific broadcasts.^6,10,11 This makes it an essential tool for maximizing the benefits of Auracast in various settings.

The new specifications introduce the ability to use encrypted Auracast broadcast codes, adding a layer of privacy to your listening experience. Broadcast transmissions can be private (encrypted) and open (unencrypted).¹² This is especially useful for personal or sensitive transmissions, in more controlled listening environments. For more general or public use,  broadcasts are recommended to be unencrypted, making it easily accessible to anyone within range. This flexibility allows Auracast to cater to a wide range of scenarios, from personal listening sessions to large public broadcasts, all while maintaining control over who can tune in.

To determine if a device supports Auracast, first check its technical specifications and Bluetooth version, ensuring it supports Bluetooth LE Audio (introduced with Bluetooth 5.2).¹² Look for broadcast capabilities in the device’s settings or firmware updates, as Auracast relies on these features for simultaneously broadcasting audio to multiple devices. Additionally, manufacturers might explicitly mention support for Auracast if the device is intended for use in environments where this broadcasting feature is prevalent, such as in public venues or modern home entertainment systems.

Accessibility and Daily Life

Bluetooth LE Audio and Auracast broadcast are set to revolutionize accessibility and significantly enhance patient outcomes across various aspects of daily life. These cutting-edge technologies offer unprecedented improvements in how individuals, particularly those with hearing loss, interact with their environments.

In public spaces like theaters, lecture halls, conference rooms, and transportation hubs, Auracast enables direct audio streaming to hearing aids and other Bluetooth-enabled devices, eliminating the need for traditional assistive listening systems that often require cumbersome additional equipment. This seamless integration fosters a more inclusive experience for all users.

Auracast and BT LEA can benefit in the educational sector by allowing students to connect their hearing aids directly to educational content. This ensures uninterrupted access to information and helps create more inclusive learning environments. These technologies enhance inclusivity in workplaces by enabling employees to connect their hearing aids effortlessly to meetings, presentations, and collaborative spaces, ensuring full engagement and participation. At home, integrating Auracast into personal entertainment systems and electronic devices offers a seamless audio experience that benefits both hearing aids and those with normal hearing, creating a more inclusive and enjoyable environment for everyone. By incorporating Auracast into daily activities, individuals with hearing loss can experience a significant improvement in their quality of life, enjoying a new level of audio accessibility in all aspects of their daily routines.

Additionally, the impact of this technology extends into specialized fields such as aural rehabilitation and speech therapy, where they can enhance therapeutic outcomes by providing clearer and more efficient audio transmission. This is crucial for effective communication and learning. This type of integration opens exciting opportunities for research and development, promising to further enrich the fields of audiology, speech-language pathology, education, and workplace inclusivity.

Comparative Analysis: Auracast vs. Traditional Hearing Solutions

Bluetooth Auracast is set to revolutionize how we experience sound by complementing, rather than replacing, traditional hearing solutions like hearing loops. While systems such as telecoil and FM have long been crucial for individuals with hearing loss, Auracast introduces a new era of accessibility and convenience, taking auditory experiences to new heights. Unlike traditional telecoil systems, which depend on specific infrastructure and can be affected by interference, Auracast offers a state-of-the-art, flexible, and portable solution. It leverages Bluetooth LE Audio to stream high-definition audio directly to hearing aids, delivering unparalleled clarity and minimizing latency. This means users can enjoy richer, more detailed sound with less delay, enhancing their overall auditory experience.

Auracast can transform the user experience by eliminating the need for cumbersome additional equipment and complex setup procedures. Users can connect effortlessly to broadcasts in various environments, without the hassle of handling multiple devices. Its capability to stream directly to multiple devices simultaneously is particularly advantageous in challenging listening environments such as large auditoriums or noisy public spaces, where traditional systems may fall short.

While classic solutions like telecoil and FM systems remain invaluable, Auracast significantly enhances the spectrum of hearing technologies by offering superior clarity, simplicity, and user satisfaction. It bridges the gap between the well-established technologies and contemporary needs, representing a major step forward in hearing aid technology and enriching auditory landscapes.

Conclusion

As we stand on the brink of a new era in broadcast audio technology, Auracast broadcast is not just a step forward—it’s a leap into the future of wireless communication. Still in its early stages, this groundbreaking innovation is set to revolutionize how we experience sound in public and private spaces. Auracast is the example of audio accessibility being no longer a luxury but a standard. Whether you’re in a bustling transportation hub, a crowded theater, stadium, or the comfort of your living room, Auracast will deliver high-quality, synchronized audio directly to your personal device, making every moment more immersive, inclusive, and connected.

What makes Auracast truly exciting is its potential for explosive growth. According to industry experts, the next few years will see a dramatic increase in the adoption of Auracast-enabled devices and broadcasts. This technology is set to become ubiquitous, transforming not just hearing aids and earbuds, but how we experience our public and private soundscapes. Imagine a world where every venue, from theaters to museums to sports arenas, waiting areas to lecture halls, is equipped with Auracast, making it possible for millions of people—regardless of hearing ability—to tune into the same audio experience with unparalleled clarity and ease.

As Auracast gains momentum, it will enhance how we listen and create new opportunities for accessibility, inclusivity, and innovation. The rapid development and deployment of Auracast technology will unlock a future where seamless, high-quality audio can be experienced. This revolution is how we connect with the world around us- where everyone can hear and be heard. The future of sound is here, and it’s more thrilling than ever!

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References

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8. A Technical Overview of LC3 [Internet]. Bluetooth® Technology Website. 2020. Available from: https://www.bluetooth.com/blog/a-technical-overview-of-lc3/
9. Bluetooth SIG. ”Performance Characterization of the Low Complexity Communication Codec”. Technical white paper. Version 1. 2023 Jun 13.
10. Specifications | Bluetooth® Technology Website [Internet]. Bluetooth® Technology Website. 2019 [cited 2024 Sep 4]. Available from: https://www.bluetooth.com/specifications
11. Auracast - How It Works | Bluetooth® Technology Website [Internet]. Bluetooth® Technology Website. 2019 [cited 2024 Sep 4]. Available from: https://www.bluetooth.com/auracast/how-it-works/
12. Answers to Commonly Asked Questions About Auracast^TM Broadcast  AudioAuracastTechnology Website [Internet]. Bluetooth® Technology Website. 2023 [cited 2024 Sep 4]. Available from: https://www.bluetooth.com/blog/answers-to-commonly-asked-questions-about-auracast-broadcast-audio/