Wireless audio transmission is unavoidable these days, especially when it comes to audio on-the-go. The progressive removal of headphone outputs on smartphones has driven users to purchase Bluetooth earphones, Bluetooth headphones and, more recently, True Wireless earphones, which are also connected via Bluetooth.
During CES 2020, the Bluetooth SIG (Special Interest Group) presented the next generation of the famous wireless transmission protocol that is designed to provide serious improvements in audio quality. Called LE Audio, this new Bluetooth standard will gradually replace the old Classic Audio standard.
Expected to be released in 2021, the first audio devices to adopt Bluetooth LE Audio will probably still be compatible with the old version to ensure backward compatibility with smartphones that aren’t already LE Audio compatible.
Bluetooth LE Audio: based on Bluetooth Low Energy
As their names suggest, the Classic Audio standard is based on classic Bluetooth radio transmission while the LE Audio standard is based on Bluetooth Low Energy radio.
In addition to improving the quality of audio transmission over Bluetooth headphones, earphones and speakers, the LE Audio standard introduces new features that allow new, more efficient Bluetooth devices and applications to be developed.
Bluetooth LE Audio: new LC3 codec
Bluetooth LE Audio includes a new high-quality audio codec that isn’t processor intensive, therefore requiring little power. In using the best compression techniques developed by Fraunhofer Labs, the Low Complexity Communications Codec (LC3) guarantees the best audio transmission quality by using less data. The LC3 codec gives developers greater flexibility, allowing them to make better design decisions with key product features such as audio quality and power consumption.
“Extensive listening tests have shown that LC3 will provide improvements in audio quality over the SBC codec included with Classic Audio, even at a 50% lower bit rate.”Manfred Lutzky – Head of Audio for Communications at Fraunhofer IIS
Developers will be able to take advantage of these energy savings to create products with an extended battery life or, in cases where the current battery life is sufficient, reduce size by using a smaller battery.
Bluetooth LE Audio: multi-stream transmission
One of LE Audio’s major innovations is the ability to transfer multiple, independent, synchronized audio streams between an audio source device (such as a smartphone) and one or more audio sink devices. Notably, this feature will improve the performance of True Wireless earphones by allowing the smartphone or DAP to send the right or left audio stream directly to the earphone, which is not currently the case. Today’s True Wireless earphones work using a master/slave pattern in which only one of the two earpieces (the master earpiece) is connected to the smartphone and receives the entire stereo audio stream. This earpiece then sends the left and right streams to the earphones, via the wireless connection between the two earpieces.
Thanks to LE Audio, acoustic and stereo imaging will be much better with True Wireless earphones.
Bluetooth LE Audio: hearing aids
Thanks to its low energy consumption, higher quality audio codec and multi-streaming abilities, the LE Audio standard can be used for hearing aids. It will therefore be possible for the same audio stream to send a corrected sound at different volumes to one of the earpieces so that it is precisely adapted to the hearing loss of the user.
“LE Audio will be one of the most significant advances for users of hearing aids and hearing implants.”Stefan Zimmer – Secretary General of EHIMA (European Hearing Instrument Manufacturers Association)
EHIMA’s engineers have contributed their specialist knowledge to help improve the audio experience, especially for those that are hard of hearing. As a result, within a few years most new telephones and televisions will be accessible for users with hearing loss.
Bluetooth LE Audio: Broadcast compatible
The LE Audio standard has more than one string to its bow and supports Broadcast Audio, which allows an audio source to broadcast one or more audio streams to an unlimited number of audio sink devices. This compatibility with Broadcast Audio opens up new opportunities, especially concerning audio sharing.
The Bluetooth audio sharing feature supported by LE Audio can be personal or location-based.
With personal audio sharing, people will be able to share their Bluetooth audio experience with others around them. For example, it will be possible to share music from a smartphone with friends that have LE Audio Bluetooth earphones or headphones, or to stream music from a smartphone to several Bluetooth speakers at the same time.
With location-based audio sharing, public venues such as airports, sports bars, gyms, cinemas, and conference centers can share Bluetooth audio that improves the visitor experience.
Bluetooth LE Audio: compatibility
The LE Audio standard isn’t compatible with the Classic Audio standard of current Bluetooth devices. To enjoy the features offered by Bluetooth LE Audio, the source (smartphone, DAP, computer…) and transmitter (Bluetooth earphones, True Wireless earphones, Bluetooth headphones, Bluetooth speakers…) will both have to be LE Audio compatible. An LE Audio source won’t be able to send sound to a Classic Audio transmitter, and vice versa. Consequently, when making a purchase it is important to check which standards are supported to avoid being disappointed due to incompatibility. Let’s hope that manufacturers start by using Bluetooth controllers that are adapted to both standards in their devices so that users won’t have to change all of their equipment at once…
Eventually, the Bluetooth Classic Audio standard will be replaced by Bluetooth LE Audio.