August 19, 2022

Scharon Harding

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

With today’s announcement, it’s the perfect time to 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 hard to pinpoint because they’re based on individual vendors. However, in its announcement, Bluetooth SIG said that the first consumer offerings “are expected to come to market in the coming months, and the Bluetooth SIG anticipates LE Audio product availability to ramp up as we approach the holiday season and end of the year.”

Bluetooth SIG today announced the full set of specifications for Bluetooth LE Audio. This is great news because when it first announced Bluetooth LE Audio in January 2020, the expected spec release date was in the first half of 2020. And work on the spec has been ongoing since at least 2015. Apparently, Bluetooth LE Audio was the “largest specification development project in the history of the Bluetooth SIG,” according to a statement from Mark Powell, Bluetooth SIG’s CEO.

The industry group also said today that companies could earn the qualification to add Bluetooth LE Audio support to their products.

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Why Bluetooth LE Audio?

Today’s Bluetooth devices either use a form of standard Bluetooth, like Bluetooth 5.2, also known as Bluetooth Classic, or Bluetooth LE, which prioritizes power efficiency. Bluetooth Classic, however, has been more appealing to audio devices, like wireless headphones, over Bluetooth LE. That’s because standard Bluetooth can reach a higher throughput by more frequent continuous radio usage, as explained by Nordic Semiconductor, a Bluetooth SIG member whose products include a Bluetooth LE Audio SDK. Bluetooth LE, contrastingly, uses its radio for the shortest possible time to conserve power.

Bluetooth LE Audio standardizes how audio is transmitted over Bluetooth LE using a new block-based transform codec called Low Complexity Communication Codec (LC3). The codec offers improved audio quality compared to Bluetooth Classic’s Sub-band Codec (SBC) while continuing the power-efficiency focus of Bluetooth LE.

For example, Bluetooth SIG has stated that while Bluetooth Classic’s SBC codec will usually encode a 1.5 Mbps audio stream to a 345 Kbps (0.345 Mbps) stream, Bluetooth LE Audio can compress the same stream at 160 Kbps (0.160 Mbps) and claims better audio quality than Bluetooth Classic.

As explained by audio publication SoundGuys, the SBC codec ranges from 345-240 Kbps. The bar graph below compares perceived impairment—ranging from very annoying (1.0) to imperceptible (5.0), as defined in the ITU-R’s BS.1116-3 [PDF]—for the SBC and new LC3 codecs.

You can look at Bluetooth SIG’s claims via the bar graph below, which claims Bluetooth LE Audio delivers audio quality that’s perceived better than Bluetooth Classic at the same or even lower data rates.

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Bluetooth SIG's expectations.
Enlarge / Bluetooth SIG’s expectations.

You can also hear purported differences in Bluetooth SIG’s Audio Codec Demonstration.

When Bluetooth SIG first announced Bluetooth LE Audio, it said it expected debuting LE Audio products to also support Bluetooth Classic to ensure backward compatibility with devices that lack LE Audio.