Tom breaks down the Bluetooth LE Audio profile, why it’s needed, and when and where you can expect to see it in your devices.
Featuring Tom Merritt.
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I already have Bluetooth and I have to say I’m not that impressed.
But now they say there’s Bluetooth LE Audio for my music?
Should I trust this?
Don’t be. Let’s help you Know A Little More about Bluetooth LE Audio.
Bluetooth LE Audio is an implementation of Bluetooth LE with a focus on audio quality. So what is Bluetooth LE you might ask.
Bluetooth LE stands for Bluetooth Low Energy. It’s technically separate from the regular Bluetooth spec but it’s also administered by the Bluetooth Special Interest Group ( you can listen to our episode on Bluetooth 5 for more on that. Bluetooth LE uses the same frequency as Classic Bluetooth, 2.4 Gigahertz, and it can share a radio antenna, so the two specs are often implemented together. In other words your phone, Bluetooth speaker or headphones might have one or both. But your earbuds are the most likely to have Bluetooth LE in order to save on battery life.
Let’s take a quick dip into where it came from. Nokia researchers adapted Bluetooth in 2001 for low power use and in 2004, published something they called Bluetooth Low End Extension. Continued development with Logitech and other companies including STMicroelectronics led to a public release under the name Wibree in October 2006. The Bluetooth SIG agreed in June 2007 to include Wibree in a future Bluetooth spec, but sadly did not agree to keep the name. It was integrated into Bluetooth 4.0 as Bluetooth Low Energy and marketed as Bluetooth Smart. The iPhone 4S was the first smart phone to support it in October 2011. The Bluetooth Smart name was phased out in 2016. It’s now just called Bluetooth LE, currently grouped under Bluetooth 5. So yes it’s *technically* not the same but it essentially works like a mode of classic Bluetooth. (Pause for shouting of people who say it’s not like that at all, really).
Bluetooth SIG defines profiles for both Bluetooth Classic and Bluetooth LE, basically a definition of how it works for a particular application. One of the LE profiles is the Mesh profile which lets LE devices forward data to other LE devices to create a mesh network. There are a lot of profiles including battery, proximity sensing, internet connectivity, and… tada! Audio.
Since for many folks, Bluetooth means headphones and speakers, the official publication of the Bluetooth LE Audio profile got a lot of attention.
Bluetooth LE Audio’s protocol defines features that expand what low-power devices can do, specifically for audio.
Some of what Bluetooth LE Audio can do already exists. Qualcomm’s aptX Adaptive or Sony’s LDAC codecs offer high quality audio compression and low latency. You just need to pay Qualcomm or Sony to use them. Or you could engineer your own proprietary solution. Which costs you the time to research and develop it.
But you don’t need any of that anymore.
Bluetooth LE Audio will support up to 48 kHz, 32-bit audio at bitrates from 16 to 425 Kbps, with 20-30millisecond latency versus Bluetooth Classic’s 100-200 millisecond latency, all while going easy on your battery. And it costs a manufacturing company exactly nothing to implement. The magic of industry standards.
Instead of LDAC or aptX, Bluetooth LE Audio uses the LC3 codec. It can deliver higher quality audio at the same bitrate as Bluetooth Classic’s SBC codec and SIG claims it can do better audio than SBC at half the bitrate. That means higher quality audio will use less power.
There’s also a feature called Auracast which lets unlimited audio devices – called “sinks” in the parlance – but we’re talking about speakers and headphones what have you – connect to a single audio source. For instance everybody in the gym could connect their wireless headphones to a single TV. Everybody in a theater could wear earbuds to get improved movie audio. Users can select Auracasts like they would a WiFi network. Depending on how the OS handles them they’ll probably show up as a little list of ‘Auracast Broadcasts” and you would select from the list the one you want to hear. Auracast also supports connections by QR code and NFC, so that may be an option sometimes too. And yes, Auracasts can be password protected if you just want to share with friends, and those can show in the list with a lock.
Here’s another example SIG gives, airport gate announcements. Let’s say you’re at gate C17. There could be an auracast just for gate C17 and then a password-protected one for the gate agent. That way the gate agent hears the airport announcements meant for them and you hear just the announcements for your gate and don’t get confused by that “board now” announcement from C18 next door.
Now you may be wondering how you’ll see that list of Auracasts on your small earbuds. You’ll need an “assistant” most often a smart phone- though I suppose it could be a laptop or tablet or some such thing. On the “assistant” device you select the broadcast. The assistant then passes on the information to connect to the headphones or speaker which then connect to the broadcast directly. You won’t be dragging down the battery of the assistant device after that.
A few other notable features.
Bluetooth LE Audio also lets each earbud maintain its own connection with the source device. Right now with Bluetooth, only one earbud connects to the source device and then somehow passes along the audio to the other earbud. This is a tricky thing since the head blocks most wireless connections so you have to find a way around it. That’s why the first wireless headphones always wired the two earphones together. Apple lets each earbud in its airpods make a direct connection to an iPhone but that method is proprietary. With Bluetooth LE Audio, more earbud makers can do it as part of the spec. Word is Apple will adopt Bluetooth LE Audio as well, whether they use it for this feature or not.
This should also make it easier to switch between audio source devices.
Bluetooth LE Audio is also better at managing packet loss when you’re at the edge of the range. Bluetooth LE– without the Audio profile– tries to make sure every packet arrives. And if it can’t, it terminates the connection and then reconnects and starts over. This is a good thing when you want to get every bit in a file. For audio streams though, it means your audio cuts out more when you’re at the edge of the range. Bluetooth LE Audio, since it’s specific to audio, takes a different approach to packets. It limits the time a packet has to to be retransmitted so that once it’s too old to matter, you know it’s the “oooh-we-oo” from the last verse– it gets tossed aside and doesn’t cause the stream to be interrupted. The new LC3 audio codec can compensate for this packet loss so you don’t hear skipping. And it should work the way Qualcomm’s aptX Adaptive or Sony’s LDAC codecs have worked over Bluetooth up until now, by reducing the quality a little until the connection gets stronger. So basically instead of skips and dropouts at the edge of the range you may just get slightly tinnier sound.
And praises be, Bluetooth LE Audio supports hearing aids and implants. A huge benefit for devices that really do need battery efficiency. Bluetooth SIG expects most new phones and TVs to be hearing loss accessible within the next few years.
So how can you get it?
Some devices may be able to support Bluetooth LE Audio with a software upgrade so check with your manufacturer to see. In fact Android 13’s beta supports it already. But will they? Maybe? However, maybe not. Your best bet is to check for new devices to see if they support it.
You should be able to find more and more products supporting Bluetooth LE Audio over time. In other words, I hope you know a little more about Bluetooth LE Audio.