What is Bluetooth LE Audio? Explanation of the specification and its meaning for wireless audio

On Tuesday, the Bluetooth Special Interest Group (SIG), the industry group behind the Bluetooth wireless communications standard, announced the completion of its latest specification: Bluetooth Low Energy (LE) Audio. Like Bluetooth LE, Bluetooth LE Audio focuses more on energy efficiency than classic Bluetooth. It also aims to provide better sound quality than standard Bluetooth and introduces new features.

With today’s announcement, it’s time to take a look at Bluetooth LE Audio and what it means for future tech gadgets.

Bluetooth LE Audio release date

There are no Bluetooth LE Audio products available yet and release dates are difficult to determine because they are based on individual vendors. However, in its announcement, the Bluetooth SIG said that the first consumer offerings are “expected to hit the market in the coming months, and the Bluetooth SIG expects LE Audio product availability to increase as the holiday season and year-end approaches.””

The Bluetooth SIG today announced the full set of specifications for Bluetooth LE Audio. This is great news because when the company first announced Bluetooth LE Audio in January 2020, the expected release date for the specs was in the first half of 2020. By all accounts, Bluetooth LE Audio was “the largest specification project in the history of the Bluetooth SIG”. According to Mark Powell, CEO of the Bluetooth SIG.

The industry group also said today that companies can qualify to add Bluetooth LE Audio support to their products.

Why Bluetooth LE Audio?

Modern Bluetooth devices use either the standard form of Bluetooth, such as Bluetooth 5.2, also known as Bluetooth Classic, or Bluetooth LE, which prioritizes energy efficiency. However, Bluetooth Classic is more attractive for audio devices like wireless headphones over Bluetooth LE. This is because standard Bluetooth can achieve higher throughput through more frequent continuous use of the radio, as explained by Nordic Semiconductor, a member of the Bluetooth SIG whose products include the Bluetooth LE Audio SDK. Bluetooth LE, on the other hand, uses its radio communication for the shortest amount of time to save power.

Bluetooth LE Audio standardizes Bluetooth LE audio transmission using a new block-based transformation codec called the Low Complexity Communications Codec (LC3). This codec provides improved audio quality over the Bluetooth Classic Subband Codec (SBC) while maintaining the power efficiency of Bluetooth LE.

For example, the Bluetooth SIG has stated that while the Bluetooth Classic SBC codec typically encodes a 1.5 Mbps audio stream into a 345 Kbps (0.345 Mbps) stream, Bluetooth LE Audio can compress the same stream at 160 Kbps (0.160 Mbps) and claims the best sound quality. quality than Bluetooth Classic.

As audio publication SoundGuys explains, the SBC codec ranges from 345-240 Kbps. The histogram below compares the perceived distortion, ranging from very annoying (1.0) to subtle (5.0), as defined in ITU-R BS.1116-3 [ PDF ] for SBC codecs and the newer LC3 codecs.

You can read the Bluetooth SIG claims in the bar graph below, which states that Bluetooth LE Audio delivers sound quality that is perceived better than Bluetooth Classic at the same or even lower data rate.

You can also hear the alleged differences in the Bluetooth SIG audio codec demo.

When the Bluetooth SIG first announced Bluetooth LE Audio, it stated that it expects debut LE Audio products to also support Bluetooth Classic to ensure backward compatibility with devices that lack LE Audio.