Auracast

Auracast could be awesome.

If you’ve ever been frustrated by trying to “just listen to some music” on any ridiculously dysfunctional combination of phones, various proprietary (and buggy: looking at you, Chromecast) casting technologies overlaid on unreliable WiFi networks, or the short range and short-sighted “nobody will ever need more than 1 source and sink” A2DP Bluetooth connectivity, then Auracast looks to be a gift from the gods.

It might sound odd, but Auracast is really retro: Auracast is little more than a modern take on the old fashioned low-power analogue FM radio transmitters that your (grand)father/mother may have used last century to get music from their iPod to a stereo or car radio. Except now it’s a higher quality digital transmission, and of course connected to your phone/devices.

BTW, I’m purposely not calling this new magic “Bluetooth Auracast” - even its owners, the Bluetooth SIG, don’t call it that - they want to disassociate from all the negative vibes that “Bluetooth” has accumulated over the past 20+ years. And rightly so, my experiences thus far - with one exception that is 100% at JBL’s feet - is that Auracast has none of the common “Bluetooth” problems:

• 1:1? Nope: this is pirate radio time! Everyone’s a (local area) broadcaster!
• short range? Nope: “up to 100m”, for real (tested one device through a brick wall and then 98m of open ground: a-ok; a headset started hiccuping at about the 91m mark)
• low quality? Nope: 48kHz LC3 (default is lower to support hearing aids)
• high latency? Nope: can be as low as 10ms (20ms for 48kHz)
• secure? no, but it wasn’t meant to be: this is broadcast radio: if you want to broadcast your secret plans to an audience of thousands except for that one guy, Auracast is not for you

The catch at present: as of mid-2025 it’s still “too new” and there are many half-baked implementations. One of the most egregious examples is JBL: despite apparently licensing the Auracast trademark, etc, their products cannot be used to receive from non-JBL Auracast transmitters. Their app provides no facility to scan for or select arbitrary broadcasts (they seem to have hard-coded a stream ID in their devices?). Hopefully they will provide an update at some point that properly supports Auracast.

Quality

Auracast provides two quality levels:

• Standard Quality (SQ) - 16 or 24kHz sampling rate
• High Quality (HQ) - 48kHz sampling rate (“up to CD quality”)

All Auracast transmitters must support SQ and may optionally be reconfigured for HQ, or both simultaneously. If shopping for a transmitter for music/etc, you will want to look out for a HQ transmitter. Transmitters used in public spaces are mandated to always transmit a SQ stream, and in addition a HQ stream if desired. This guarantees all Auracast receivers will work yet allows higher-quality receivers as an option. Personal transmitters can get away with one or the other. For example, the HomeSpot BA210 has a button that can be used to switch between SQ and HQ - but can’t do both at the same time. The difference in sound quality for music, even to my poor hearing, is quite significant, and I have HQ receivers so I run the transmitter in HQ.

JBL do not provide a means to switch stream quality - for JBL to be in compliance with the Auracast standard they must be simultaneously transmitting both SQ and HQ, however I see no indication they are.

Latency And Reliability

Auracast allows a transmitter to select from a handful of different latency options: the higher latency versions afford greater resilience to interference (i.e. higher latency equals more reliable).

The Three Players

Auracast requires three things:

1. a Transmitter
2. a Receiver
3. an Assistant for the Receiver

The Transmitter can be easy: this can be a phone, a dongle you plug into your vinyl record player, a fancy box you install in a public arena, or even a “bridge” that has a BT A2DP receiver on one side and a Auracast transmitter on the other (some JBL speakers can act this way, as can the FlooGoo FMA120).

The Receiver is simple: it’s the headset, speaker, earpiece or other device receiving the broadcast and turning it into audio. There’s nothing to configure, which is just as well as receivers are often small and absent any sophisticated user interface (a button or two at best). e.g. the HomeSpot JY300 earphones have a button that switches through a number of preconfigured broadcasts.

The Assistant is the user interface for the Receiver: it’s what you use to configure the Receiver - to “tune the Receiver in” to a broadcast. This is typically an app on your phone, but could also be a small touchscreen on a Receiver case for example (as with the JBL Tour Pro 3 earbuds).

This is also where it can get confusing: the connection between the Assistant and the Receiver is often via traditional non-broadcast Bluetooth, this requires pairing your Receiver to your Assistant but only for the purposes of control, not audio. For example the QKAudio app on the phone is used to create presets on the HomeSpot JY300 earphones (a Receiver). Once preset, you can disconnect the phone and pick between the broadcasts using the ‘circle’ button on the headset.

JBL

JBL prominently advertise “Auracast” for their newer range of speakers. However they currently provide no facility to receive Auracast broadcasts from other transmitters - i.e. they do not provide an Assistant. Their existing companion app would be the right place to provide an Assistant and would expand their utility greatly.

A Word on Security

Auracast use the terms “open” and “closed” for non-encrypted and encrypted streams; this gives you an idea of the use cases they intended: an open area (e.g. one big stadium), or a closed area (e.g. a theatre in a cinema multiplex). Not “secure”.

I have to wonder what use case someone has for “securely” transmitting a radio signal to countless receivers. The Annual Conference of Evil Doers, perhaps? Though I’m sure Mr Bond would simply scan the QR code provided to all attendees, or pick up one of the “secured” headsets at the door, and happily listen in.

Auracast encryption is not intended to be secure, it is and does address two real-world problems:

1. selectivity: Auracast may well become ubiquitous anywhere audio is broadcast: railway stations, conference centres, theatres, and so on; all of these require selectivity. Radio does not respect walls - if you’ve ever tried to pick a particular WiFi SSID in the CBD of a modern city, you’ll know why being able to just scan a QR code and connect is a nice feature to have. Encrypted broadcasts are hidden so they don’t clutter up the list of open streams.
2. confidentiality in the “I’m whispering to the person sitting next to me” meaning of the word, not “I’m conveying nation-state secrets”: a passcode at least means someone has to make a token effort to lean in and overhear; Auracast is made for you and I, not for the UN Security Council

Auracast does have one unfortunately likely real-world problem that is inherent to any radio service: a malicious actor (vandal/mischief maker) in the broadcast audience can - with the right tools - hijack the radio transmission from the legit transmitter, and substitute their own instead. This is largely the same problem from the days of pirate radio.

Encryption is enabled or not independently of stream quality settings, however some implementations conflate the two. i.e. the HomeSpot BA210, in SQ transmission mode, always sends a non-encrypted stream; in HQ mode it enables encryption by default, you need to use a configuration app to disable encryption.