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How LE (Low Energy) Audio is set to transform the listening experience


24th February - Valencia.

"The goal of Bluetooth LE Audio is to provide a set of tools that will cope with any wireless audio application — any combination of music and voice — that anyone is likely to come up with for the next 10 to 20 years." Nick Hunn, CTO Wifore Technology


An exciting future with LE Audio

The road has been long and winding but LE Audio, standing for ‘Low Energy’ Audio, is set to transform the quality and ways we consume sound. Not only will Bluetooth LE Audio allow audiences to hear and share our work in much higher quality, but the new standard is so flexible that it may very well spark new ways to conceive sound-centric art and entertainment.

Having been released at CES show 2020 by the Bluetooth SIG as part of Bluetooth 5.2, The Bluetooth LE Audio standard allows devices to transmit sound streams across the low-energy spectrum, but it will do so using a new compression algorithm (LC3) that maintains the same high audio quality you get from Bluetooth right now. Manufacturers who build products to match the new set of specifications can design wireless products that get nearly double their current play time, or even shrink the battery to reduce the overall device size.

The goal is to transmit a high-fidelity signal at the minimum bit rate. Doing so minimises space and bandwidth requirements for storage and playback. A low bit rate results in greater compression and reduced audio quality. Meanwhile, a high bit rate results in less compression and greater audio quality.


Change in Profiles and codecs and synchronicity

Bluetooth has always been synonymous with wireless audio.  As part of the Bluetooth classic protocol for audio, an audio streaming profile has been used to transmit audio data. ‘Profiles’ are pieces of code that define possible applications and use cases: they specify the general ways that Bluetooth devices communicate with each other. The first audio profile that Bluetooth developed was Headset, which was soon replaced by Handsfree to accommodate car connectivity. It was intended for wireless, single-sided headsets in call centres or cordless phones at home.

Then in 2006, Bluetooth released another audio profile, A2DP, which allowed for higher-quality audio transmission. A2DP was designed to unidirectionally transfer an audio stream in up to two-channel stereo from one device to another. In addition a codec (short for “compression/decompression”) complex algorithm was used to process audio data to make it smaller so it would be easier to send over the Internet or wirelessly from your phone to your headphones.

Some of the most popular codecs used today include SBC, AAC, aptX, and MP3. Using a codec is necessary because the less data Bluetooth needs to transmit, the more reliable the connection is.

As consumer expectations of audio quality rose, the limitations of the profiles started to become clear under Bluetooth Classic Audio. Handsfree and A2DP profiles ``don't really work together,” says Nick Hunn, CTO of WiFore Technology, because “the Handsfree and A2DP profiles were designed without anybody ever really thinking that you’d want to swap between them.” For example, if you’re listening on your AirPods to some desert blues and a phone call comes in, classic Bluetooth has to go through considerable hoops just to stop playing the song and take the call. “It’s not a clean solution,” he said.


The moves from the Hearing Aid industry

A major thrust for a new technology came from the Hearing Aid community. Hearing aids and hearing-loss prevention and treatment techniques had improved over the years, however people with hearing loss still felt restricted in certain situations, like when trying to engage in a conversation with several people talking over each other or watching a video without subtitles. ElectronicDesign. Connectivity was based on one device such as a hearing aid or headset from a smartphone. Traditional Bluetooth was also heavy on battery usage and sound quality and range was limited.

“The hearing aid industry sat down with the Bluetooth SIG and said, ‘Look, things are changing. We want to connect hearing aids, but we think there is a bigger market for this.”

Hearing Aid companies required an ability to stream to more than one device using Broadcast mode and Bluetooth standards, easy installation and low energy usage. Also with assistive listening at public venues such as theatres, gyms and cinema there needed ability to cut extraneous noise and improve synchronisation of audio with that on the phone or other devices.

Many modern products from hearing aids to ‘Apple based devices’ were building on the profile with their own stacks and codecs to achieve functionality which were otherwise not possible in each other’s ecosystem. The infrastructure was therefore cluttered and complicated.


Benefits of LC3 Codec

LE Audio will allow audio companies to revert back to standardised practises rather than create proprietary audio codecs. The new Low Complexity Communications Codec (LC3) offers better audio quality and efficiency than AptX and SBC, thus extending battery life from supported products. By accepting a standardised codec for LE Audio, companies can work together rather than against each other to provide greater flexibility and opportunities.

As an example Laird Connectivity have recently released LE Audio evaluation kits. These new kits are comprised of Laird Connectivity’s BL5340 Bluetooth 5.2 development boards, a custom audio interface board, and Packetcraft’s comprehensive software solution for LE Audio. The BL5340 is the most advanced, most secure and highest performing dual core MCU wireless solution available. This series of robust, tiny modules features the Nordic Semiconductor nRF5340 SoC and directly targets the highest performance with the lowest power budget. Packetcraft’s LE Audio solution includes the link layer, host stack, and LC3 codec. Packetcraft’s software is Bluetooth qualified and designed specifically for ultra-low power resource-constrained embedded devices. Together, these solutions provide a platform that gives developers everything needed to start creating Bluetooth LE Audio products such as wireless microphones, broadcast audio for infrastructure, and much more.

The LC3 codec has been developed by the Fraunhofer Institute and Ericsson and has led to possible transmission in the Super bandwidth of 32 kHz plus which can outperform SBC at half the bit rate. The result is that it increases battery life and provides greater flexibility, higher sound quality and noise cancellation.


The opportunities for the future

With over 20 silicon companies so far involved in developing new chips for LE Audio applications the market is set to boom for a variety of different devices which will enable new experiences including:

  1. Broadcast Audio   - for TV, gym, airport, Multi language, boosting hearing capability
  2. Audio Sharing  - Share Audio content to friends, groups etc
  3. Gaming Mode – Bi-directional stream, mobile gaming plus chat, wireless remote devices.

The type of devices will all have characteristics of:

Being long lasting, save on power consumption, including Integrated SOC, Robust connectivity, noise cancellation, higher standards, low latency, scalable, ability to personalise preferences.

The greatest opportunities will come in transitioning existing products using Classic capability where the ultimate goal will be to free the user from restricting features using LE Audio.

It therefore is no surprise that there is a great requirement for specialist embedded engineers that can optimise these market opportunities. CIS are Experts in finding the right matched people and have been finding highly skilled engineers for leading edge technologies for over 20 years. Make sure your next exciting LE Audio project opportunity is covered. Contact Aleksandra Wisna on +34 960 038 631 or on aleksandraw@cis-ee.com