Although I had heard of this new-fangled “spatial audio” now supported by Apple, my devices are all so old they are limited to good old-fashioned stereo.
And I like it that way.
I mean, just because you give “surround sound” a new name doesn’t mean I’m gonna fall for it.
And “surround sound” doesn’t work in headphones, in spite of all the demos trying to convince you that this ultra-separated stereo recording can make you think a sound is coming from in front of, behind, or above you.
I was wrong.
While I still don’t think headphone based “surround sound” is anything more than two-speaker stereo with fancy mixing, spatial audio turns out to be something quite different. And I discovered it by accident.
A few months ago, I picked up some Apple AirPods to use as noise cancelling headphones while spending many weeks working in a noisy warehouse. Being able to turn noise cancelling on and off was, on its own, a slight form of magic. At least, that’s how I felt when I first got to demo the BOSE noise cancelling headphones in the Denver airport two decades ago. Today, however, noise cancelling is built in to even cheap headphones.
I read that these AirPods supported spatial audio, but when I tried to listen to the demos it just sounded like stereo to me.
New name, same scam. Or so I thought.
Later I read that spatial audio was only supported on newer devices that the ancient ones I had. This intrigued me. Why would the device’s horsepower matter?
I learned why, quite by accident.
I swear I heard something…
I got to use a new-model iPad and was watching HULU using my AirPods. I thought nothing of it, until I turned my head to look at something. I heard the sound in my right ear.
Oops. Had I actually not turned these headphones on, and was blaring HULU through the speakers? How embarrassing.
I checked and my speakers were silent. What just happened?
I resumed playing the video, this time paying attention to the sound to see if, somehow, the iPad speakers were turning on. As I turned my head to test again, the sound was heard to shift to the closer ear.
I felt a tad bit of magic, as I realized turning my head was shifting how the audio was playing, simulating listening to a TV at a fixed point in space. I had never heard anything like this before in headphones. After all, headphone sound doesn’t move.
And now I know what makes spatial audio more than just surround sound. Sensors in the headphones, combined with processing in the playback device, are able to create custom mixes of the audio as your head moves. It’s difficult to describe, beyond just saying “it’s as if the sound was real and you weren’t wearing headphones.”
If your iDevice supports it, there is even a test built in to the Bluetooth connection settings for the AirPods:
When I first tried this demo, I switched from Stereo Audio to Spatial Audio and it just sounded like a better stereo mix. But when I tried again, now aware of what spatial audio was, I found I could turn my head away from the screen and the audio mix sounded like it was coming from the screen to the left or right of me, depending on where I turned.
Very cool magic.
While I was a two-speaker surround-sound denier (I still am), I am definitely a believer of spatial audio.
Not all apps support it, but the ones that do provide a very new experience when using headphones to listen to audio.
Until next time…
Google “Head related transfer functions”
Interesting. So the thought is it recreates a sounds that our brain is interpreting. I was big into binaural sound when that was all the rage with early podcasts, but it never sounded any different than stereo to me except for the effects they would do with it. I suppose this is like that, but the demos don’t really make me think to look up, or behind me, etc.
Congratulations. Now Apple can not only track where you are via Bluetooth, they can also track your head movements and for example tel which sounds cause you to move your head. And we pay for being able to be monitored.
At least it’s just for their own corporate profits, and not to sell to advertisers? #LesserOfTwoEvilsIsStillEvil