Immersive 360-degree sound formats like Apple’s spatial audio are increasingly looking like the next big thing in consumer audio tech. Giants like Samsung and Sony already have their own equivalents, and Apple has made spatial audio a key feature of the AirPods Pro the AirPods Max.
But what exactly is spatial Audio? How does it work, and most importantly, how can you start using it? Keep reading this spatial audio guide and we’ll show you.
What is spatial audio?
Spatial audio is how Apple brands its immersive, 360-degree sound tech, though the concept is sometimes referred to as “spatial audio” in more general terms as well. It’s essentially a form of surround sound wherein the origin points of different sounds stay in place even as you move around.
That sounds like plain, old, living room surround sound, right? Except spatial audio can keep those origin points in place even when the speakers themselves are moving, namely on headphones like the AirPods Pro and AirPods Max.
Say you’re watching a film on your iPhone where someone is loudly walking along the left of the screen. If the movie is compatible with spatial audio, you could turn your head to the left and the footsteps would then sound like they were coming from straight in front of you.
Being a form of 360-degree audio, spatial audio’s effect isn’t limited to a flat axis either. Like Dolby Atmos or DTS:X, spatial audio can add a sense of height, making TV and movie playback even more immersive.
How do I use spatial audio?
The most important thing is making sure you have the right hardware. Right now, the only Spatial-Audio compatible audio devices are the AirPods Pro and AirPods Max, so pick up one of those unless you want to wait for the rumored AirPods Pro 2. The AirPods Pro didn’t launch with spatial audio support, but it should download and install the required firmware automatically.
Next you’ll need a compatible source device, namely an iPhone or iPad running iOS 14.3 or later. However, not all older Apple devices will work, even if they can be updated to the requisite version. Here’s a list of spatial audio-compatible devices:
- iPhone 7 or later
- iPad (6th Gen) or later
- iPad Air (3rd Gen)
- iPad mini (5th Gen)
- iPad Pro 12.9 inch (3rd Gen) or later
- iPad Pro 11 inch (1st gen) or later
With these two devices you’re almost set, and remember that you can turn spatial audio on or off at your choosing. To turn if off while you’re already watching a video, open the Control Center, press and hold the volume control then tap on the spatial audio option to disable it.
To turn spatial audio on or off for everything, open Settings and navigate to the Bluetooth menu. In the list of connected devices, tap the “i” icon next you’re your AirPods then select whether to turn spatial audio on or off.
Also important to note is that media content must be available in the 5.1, 7.1 or Dolby Atmos surround sound formats for it to work with spatial audio. Unfortunately this means you can’t currently listen to music using Spatial Audio, as most tracks and albums are only produced in standard stereo.
Some music streaming services provide Dolby Atmos-compatible tunes, namely Amazon Music HD and Tidal. Still, Amazon limits Atmos playback to its own Echo speakers and Tidal seems to be keeping its immersive capabilities exclusive to Sony’s Spatial Audio rival, 360 Reality Audio. As such you can’t get spatial audio music from either.
You do at least have a choice of where to stream compatible TV shows and movies. Apple TV Plus, HBO Max, Disney Plus and Hulu all support spatial audio via their respective Atmos-enabled content. And, while Netflix isn’t currently on the list of compatible services, recent rumors suggest it could be testing spatial audio support for a full launch later this year.
How does spatial audio work?
There's a few things that are needed to make spatial audio happen. First, sound engineers will map the individual audio parts of a piece of content — dialogue, sound effects, non-diagetic music and so on — to specific points on a digital 3D space. Imagine a sphere build around the listener, with each sound source placed around it. This allows for those individual sounds to seemingly come from either side, behind, above or below you. Engineers can also adjust the “distance” of sounds so that they seem closer or further away.
Obviously, headphones don’t have a series of satellite speakers for “true” surround sound, and they can’t achieve a sense of height by bouncing sound off ceilings like Dolby Atmos does. So spatial audio’s surround sound effect needs to be purely digital.
Here’s where it gets a little complicated. 360-degree audio playback on headphones is achieved though Head Related Transfer Function (HRTF) filters, which digitally adjust how sounds are played so that they bounce into your ears in such a way that they appear to originate from a certain direction. It requires both ears for your brain to perceive the intended effect, which is why the technique is known as “binaural rendering.”
The extremely basic version is that your brain is tricked into thinking you’re receiving sound from a fully three-dimensional space even when it’s coming from a set of two drivers either side of your head.
Once the matter of fitting surround sound into a pair of headphones is settled, spatial audio can then use head-tracking to create that feeling of being able to love around (or at least look around) the 3D space. The AirPods Pro and AirPods Max therefore contain accelerometers and gyroscopes, which can track your head movements in relation to an anchor device: the phone or tablet that the headphones are paired to.
Because the anchor device contains the screen on which you’re watching the spatial audio-mastered content, the system can make sure that sounds are played from directions consistent with the on-screen action. All while you can move your head around inside that 3D space.