Today, audio devices depend upon the use of Bluetooth Classic radio, also referred to as Bluetooth Basic Rate/Enhanced Data Rate (BR/EDR), a low power radio that streams data over 79 channels in the 2.4GHz unlicensed ISM (industrial, scientific, and medical) frequency band. Supporting point-to-point device communication, Bluetooth Classic is mainly used to enable wireless audio streaming and has become the standard radio protocol behind wireless speakers, headphones, and in-car entertainment systems. The Bluetooth Classic radio also enables data transfer applications, including mobile printing.

As the names suggest, Classic Audio operates on the Bluetooth Classic radio while LE Audio operates on the Bluetooth Low Energy radio. The Bluetooth Core Specification was enhanced in December 2019 to enable delivery of audio over Bluetooth LE, including the new LE Isochronous Channels feature - that didn't change. LE Audio will not only support development of the same audio products and use cases as Classic Audio, it will introduce "a new set of features that promise to improve their performance as well as enable the creation of new products and use cases," according to the Bluetooth SIG.

Bluetooth LE Audio builds on the 20+ years of industry experience and technology developments to enhance the performance of Bluetooth audio. It introduces the new Low Complexity Communications Codec (LC3), originally developed by the Fraunhofer Institute, also the source for the Advanced Audio Coding (AAC) technology and more recently the more advanced open standard LC3plus codec that combines support for high-resolution audio with low delay.

The new specification defines the use of LC3 audio codec, chosen for its robust low-power implementation possibilities - extremely suitable for hearing-aid applications - although not yet evolving toward the possibilities enabled by the LC3plus codec or similar technologies already available. The new set of LE Audio Specifications that are now finally released define the missing elements in the original 2020 framework, with the last one being the Public Broadcast Profile (PBP), which defines global, interoperable support for broadcast audio use cases, such as public address systems and televisions. The final specification now downloadable (approved July 5, 2022) defines "how a Broadcast Source can use extended advertising data (AD) to signal that it is transmitting broadcast Audio Streams that can be discovered and rendered by Broadcast Sinks that support commonly used audio configurations."

Another document that demands more attention is the Telephony and Media Audio (TMAP) Profile v1.0 that defines the set of Bluetooth features by specifying interoperable configurations of the lower-level audio services and profiles. "In addition to introducing new features to Bluetooth audio, LE Audio offers a new, flexible architecture that provides an ideal platform for future wireless audio innovation, and work within the Bluetooth SIG is already underway to bring additional LE Audio features and capabilities to market," the Bluetooth SIG states.

I'm very curious to see how much differentiation these initial Bluetooth LE Audio products will represent for consumers. In my opinion, the first thing they will notice will be the audio sharing feature, which is something new, and very likely will also imply that Bluetooth products (true wireless earbuds in particular) behave much more reliably when it comes to pairing to sources, and toggle between sources.

I am certain that the implementation will vary from manufacturer to manufacturer initially, since the concept of "switching" between Bluetooth sources is not yet clear - and I hope it doesn't imply people clicking furiously on their earbuds. Today, having a set of earbuds connecting to three different sources belonging to the same user, and switching reliably (fast!) between them is still a feature on the wish list. Being able to "find" another Bluetooth audio streaming source that another user wants to share with me - when most likely I'm busy listening to my own stream - is not evident. And when it comes to Auracast broadcast audio in public spaces, I have a long list of implementation doubts the more I think about it.

There's no question that it’s up to the manufacturers to find the right interface for users to be able to "tune in" to different Bluetooth streams, and that starts unavoidably with an app interface, which in turn runs on a smartphone that in turn supports Wi-Fi, which is a much more robust and efficient way to distribute broadcast audio channels. To switch on screen-less Bluetooth devices, passcodes, NFC, QR codes, and channel scanners, all those things (might) work in some contexts but not always. Earbuds alone with touch sensors, voice commands, and even physical buttons will not cut it. Of course, there's always the possibility to combine some sort of pairing using some of the tools in the Bluetooth set - but the usability and user interaction remains unclear for now.

Sound Better? Of course, manufacturers will promote new Bluetooth LE Audio products by saying that they sound better. Yes, LC3 offers much better quality compared to SBC, but don't forget that the majority of people who truly care about audio quality and are using wireless earbuds and headphones today are hearing AAC or even aptX. So, consumers will not notice any difference, and they are not going to check the bitrate to compare...

Much more efficient? It can be. If the battery lasts longer, consumers will notice. That is a major selling point.

But just wait until we start adding features that increase usage. With marketing in the audio industry constantly promoting new audio experiences about "hearing things like you never heard it before," let's hope that Bluetooth will not create a new stigma of being only for those with hearing loss. You can bet that's what those sales guys pitching the latest Qualcomm Snapdragon Sound with aptX Lossless will say.

Another interesting angle. I noticed a recurring question on consumer tech websites: "But what’s currently unclear is whether we’ll need to buy entirely new devices to enjoy the benefits."

Well, as the saying goes, I have news for you...

That's the whole point! And not just once, but probably very regularly for the next 10 years or more, because wireless technology will keep evolving. Want headphones that last 20 years? Go wired.

For now, as way to celebrate the conclusion of this stage of specification updates, the Bluetooth SIG made a congratulatory video: https://vimeo.com/719177399/edb2978f9b

I'll confess the feeling I have after watching this video is the same feeling that I had when I reviewed Nick Hunn's book on LE Audio. That the team that worked on this for more than a decade has been so busy building what they envisaged that they didn't noticed what happened in the industry around them.

Now, does that detract from the value of what supposedly is available in the new specifications (12,000 pages, I'm told)? As described, this started with hearing aids, and it will be absolutely brilliant for hearing aids. Because that's precisely the market that has been struggling with Bluetooth, particularly since Apple released the AirPods and sold more units in one year than there are hearing aids in the world.

I think I already said what’s most important about this in my review of the book Introducing Bluetooth LE Audio by Nick Hunn. Clearly, the working group was targeting an efficient way to build on wireless audio streaming applications that Bluetooth conquered (to the surprise of many), with a more "efficient" and robust version for hearing aids. Other than that, there was the idea of creating audio sharing applications and audio broadcast, which is now Auracast. And I wrote about my concerns in my editorial the previous week.

In the book, Nick Hunn says that "a small group of users have constantly pressed for higher quality" - and will continue to do so. "Audio devotees kept clamoring for enhanced quality, with the digital age seeing calls for even higher sampling rates, lossless codecs and increased output levels. The fact that many people over 30 now have a level of hearing loss, which means they are incapable of hearing any of these ‘improvements’ doesn’t stop product marketing managers pushing for ever higher audio quality."

Being a part of this "small group of users" I know there is a disconnect because I've been working with and listening to "high-resolution audio" or "uncompressed" material and I am more interested now in knowing how we can truly transition to something more exciting, which might be spatial audio and personalized hearing with augmentation.

What I see in this "small group" are basically all the people who care about audio, have a passion for sound, and truly invest continuously in more and better equipment. And what do we see there? People who are still using cables and even have supported the industry decision to improve the 3.5mm jack with a compact balanced version, as an example. Most are willing to go the extra mile to get dedicated players and reproduction systems that support whatever is there that is better - including aptX Lossless, aptX HD, LDAC, or LDHC.

On the streaming services front, music is now available in lossless streaming quality and high resolution audio (pick one, for now...), but more importantly, there are very large companies, such as Apple, proposing that we move on from conventional stereo reproduction and embrace spatial audio with head-tracking and even HRTF profiles. And that will be done wirelessly - hence the clear need for more bandwidth and low latency.

All the required technology pieces of the puzzle are available today. They just don't fit in a specification that was written for different requirements 10 years ago.

Good thing that apparently the Bluetooth SIG is aware of this. After all, its members are precisely the very same companies that are investing today in "proprietary" or dedicated technologies and products that "go beyond" what is possible today with Bluetooth.

We just need to hope that it doesn't take another 10 years to write a specification that we need today and that could serve the very fast evolution that will take place with hearables and hearing augmentation, as another example. I truly don't believe that the companies active in this very high volume market will be willing to wait even half that long.

The part that left me hopeful is the conclusion of the recent Bluetooth SIG announcement saying clearly that, "In addition to introducing new features to Bluetooth audio, LE Audio offers a new, flexible architecture that provides an ideal platform for future wireless audio innovation, and work within the Bluetooth SIG is already underway to bring additional LE Audio features and capabilities to market."

The work starts now.

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