How Apple's Spatial Audio Works—and How It's Different From True Surround Sound

Illustration for article titled How Apple's Spatial Audio Works—and How It's Different From True Surround Sound
Image: Apple

Smartphone audio is getting a little more advanced with two new features: Apple’s Spatial Audio for AirPods Pro and AirPods Max, which was pushed out with iOS 14, and Samsung’s 360 Audio feature, available on the Samsung Galaxy Buds Pro, which works similarly to Spatial Audio but under a different name.

Both these approaches to personal audio attempt to recreate the feel of surround sound from just two audio outputs pushed into your ears—so airplanes in movies sound like they’re zooming over your head, voices sound like their originating from different points in the room, and so on. The main focus is on movie and TV shows, rather than something like, say, The Flaming Lips’ Zaireeka.

To take advantage of Apple’s Spatial Audio, you need an iPhone running iOS 14 or later, or an iPad running iPadOS 14 or later. You’re also going to need a compatible pair of headphones—at the moment that’s either the AirPods Pro or the AirPods Max.

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The Galaxy Buds Pro.
The Galaxy Buds Pro.
Photo: Sam Rutherford/Gizmodo

Once you’ve ticked all those boxes, you also need to be using an app that supports Spatial Audio to make sure it’s pushing through a media format that’s been encoded with surround sound. Disney+, Hulu, HBO Max, Plex and, of course, Apple TV+ currently support Spatial Audio (Netflix is apparently working on it), but even in these apps only a selection of content will have full support for the standard.

On the Samsung side, for 360 Audio to work as intended you need the Galaxy Buds Pro in your ears, plus a device running Android 11 with Samsung’s One UI 3.1 on top—at the time of writing, only the latest Samsung Galaxy S21 phones run One UI 3.1, but presumably older devices will get the software update further down the line.

As with the Apple format, you need to be using compatible apps, too—specifically, apps that support Dolby Atmos surround sound. At the moment, those apps include Netflix, Apple TV+, Vudu, Disney+, and Amazon Prime Video, so you should be able to find something to listen to in fully immersive surround sound on your Galaxy Buds Pro.

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Enabling spatial audio in iOS.
Enabling spatial audio in iOS.
Image: Apple

Spatial Audio and 360 Audio take the same sort of approach, basically. They interpret the surround sound metadata built into the content you’re watching—the data that tells your device which sounds are coming from where—and translates it into subtle variations inside your headphones. Obviously all the sounds are coming from the left or right of your head, but they’re simulated in such a way that they don’t always appear to be.

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Neither Apple nor Samsung is sharing too much about how the algorithms that power these effects actually work, but with both technologies the experience is made more authentic because your AirPods Pro, AirPods Max, or Galaxy Buds Pro actually keep track of the direction your head is pointed as you’re listening.

Little tricks like delays to some of the sounds you’re hearing, and tiny adjustments in volume, can be used to mimic a surround sound setup. What’s more, as you move your head and your device, the sensors embedded in the hardware should adjust so that the audio moves and adapts with you.

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Your phone might already have Dolby Atmos on board.
Your phone might already have Dolby Atmos on board.
Photo: Caitlin McGarry/Gizmodo

The end result is, in theory, the best surround sound you can expect from a phone and a pair of headphones. Traditional surround sound systems usually fill a room, with the number of speakers (either wired or wireless) matching the number of audio outputs that are available, and physically occupying the correct spaces—with a couple of speakers behind you, for example.

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Right now, Dolby Atmos offers the most promise when it comes to smartphone surround sound. There are other technologies around, including DTS Headphone:X and the emerging 360 Reality Audio format from Sony, but in terms of the broadness of support and compatibility, as well as the breadth of capabilities that it brings to the table, Dolby Atmos is leading the way.

Dolby Atmos abandons the idea of separate audio channels (like 5.1) and instead places sound in specific positions in 3D space—up to 128 tracks can be encoded if needed. However many speakers there are in your living room (or the cinema you’re visiting) can then interpret that audio data and make sure that sounds are coming from the spot where they’re supposed to be coming from. You’re not going to get the same sort of experience as you do with your home cinema, but we were pretty impressed with Spatial Audio on the AirPods Max.

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New and improved smartphone surround sound is on the way.
New and improved smartphone surround sound is on the way.
Image: Samsung

Playing content in surround sound from your smartphone through some headphones is by no means a new idea. Most newish premium phones advertise Dolby Atmos support, as do most video streaming apps, though results so far have been patchy and largely underwhelming. Dolby Atmos already claims to be able to simulate some degree of immersive audio on compatible phones, so it’s worth checking what your current handset is capable of.

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The not-so-secret ingredient with the new tech from Apple and Samsung is knowing where your head is and where your device is in relation to each other, plus (we presume) a few extra tweaks and enhancements. As we’ve said, surround sound on phones has been fairly hit and miss so far, so we’re hoping that the new tech from Apple and Samsung turns out to be a substantial upgrade.

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DISCUSSION

crashingechelon
CrashingEchelon

AirPods Pro got me excited for this feature but I haven’t used anything yet that makes use of it. On my Xbox though I bought Dolby Atmos for headphones and it feels like witchcraft. I’m using Xbox branded stereo headphones with it and I’m amazed how good it works. I almost don’t want to game without headphones on. So if Apple’s Spacial Audio works just as well as Dolby Atmos I know I’m in for a fun time. 

Also this works out for me because I’m not in a position to get a surround system to blast in the house. I am considering an Atmos soundbar though.