It's not, I assure you. It uses psychoacoustic properties of audio to simulate actual surround sound. I've been using it in gaming for years. You can literally hear when an enemy is behind you vs in front of you, and anywhere in the 360° around you. You can easily pinpoint their location in your head.
Pixel Buds Pro have this same kind of programming and you can enable it when watching surround sound content on your phone. You can even have it play regular audio but make it sound like it's coming from the direction of the phone. When you turn your head, the audio follows the phone and it sounds like the audio is coming from the phone in 3D, not just panned L or R in stereo. (I haven't played with this much, and I hope I'm not misremembering that last part which iPhone also has.)
Here's a computer generated example using these techniques. Headphones are required! Listen to this with ordinary headphones with no additional spatial processing enabled.
To my ears, it sounds like the 3 channels of the source audio are little spheres rotating around the top of my head like a halo. The music sounds distinctly different when it's behind me or in front of me. The distance away from my head is not far, though.
A technique like this will never be perfect, and this is not the best example I've heard. The best would be using my Logitech gaming headset in a game. It's not perfect because everyone's ears are shaped differently, and your brain learns the microtonal differences which your specific ears cause as sound echo's around your outer ear and ear canal. This might be why I hear these music examples as above my head while others might hear it revolve directly around their ears or perhaps a little lower than their ears.
I enjoy how ignorant people who don't understand a technology dismiss is with snark and get upvoted by others. Wait, what's the opposite of enjoy?
It's like how religious fundies with little education make fun of our best scientific theories with arguments that boil down to "I'm ignorant, so I don't believe this". Congratulations on being on the same level.
I listened to you link after commenting and it is absolutely an accurate representation of basic Spatial Audio for normal headphones! Thank you for sharing. I went through with Spatial Audio off and it astounded me, then was surprised when Spatial Audio ON made it less impressive. It’s because on Apple devices, it has the sound come more from where the video is coming from. For regular music, it doesn’t do that.
You're not supposed to listen to pre-procrssed audio like that with additional spatial audio processing. You're supposed to listen with ordinary headphones.
I got some AirBuds Proz and was blown the fuck away listening to music with Spatial Audio. I would love to try using them for games, but I’m sure they work like garbage on my Windows machines. Still, VERY cool tech.
They will just be normal earbuds on Windows, just like my Pixel Buds Pro. Even worse because I have to "forget" then rconnect the Buds from scratch every time I boot my PC. They will always say "connected" with no actual way to switch to them.
I make digital music myself. I've had that moment myself, where for a quick moment I thought, surely there could be some 'proper' way of rotating an audio source around your head.
And well, there is not, it is always just an effect thing.
As in, even in reality, our hearing is literally stereo, because we've got precisely two eardrums, two membranes that do the detection.
Yes, the ear flaps shape the sound, but you can do the same shaping with just effects. Make it a bit more muffled when it comes from behind, for example, and hope you don't need to also portray that something muffled comes from the front. And of course, always slap a heavy virtualizer effect on there.
In the end, it's smokes and mirrors that our brain then interprets as something spatial. I don't have a problem with smokes and mirrors. I do still find it humorous, though.
I don't really follow your logic, how else would you propose to shape the audio that is not "just an effect".
Your analogy to real life does not take into account that the audio source itself is moving, so their is an extra variable outside of just stereo signal -which is what spatial audio is modelling
And your muffling example sounds a bit over simplified maybe? My understanding is that the spatial stuff is produced by phase shifting the LR signals slightly
Finally why not go further? "I don't listen to speaker audio because it's all just effects and mirages to sound like a real sound, what only 2^16 discrete positions the diaphragm can be in" :p