Apple Spatial Audio

[Rick Cornish]

Has anyone checked out Apple Spatial Audio with Dolby Atmos?

I just got a pair of AirPods Max and thought I’d check it out. I found this demo, which is very well-done:

https://music.apple.com/us/album/marvin ... 1570942456

As you’d expect, the evolution from mono to stereo is much more pronounced than from stereo to Atmos. Nevertheless, it is different, though I’m not sure it’s better.

SPOILER ALERT: you might want to check it out for yourself first before you read my next comment.

To me, it sounded like the effect of some of the “widening” plugins. Works OK on some things, but adds a little hollowness (like from some frequencies that are out of phase), on other things.

What do you guys think? In the not-too-distant future, will we all be turning out Dolby Atmos mixes of all our tracks?


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[stubbsonic]

It sounds like early noise-reduction decoding, or like a complex version of dynamic expansion-- like expanding based on frequencies and pan locations. The result seems much more to reflect dynamic changes as opposed to spatial ones. It's interesting. Once I adjusted to the dynamic expansion kind of sound, it was cool to hear it that way.

Seems like an odd thing to want to do to a mix.

[bayswater]

Is there a site with a good demo that doesn't require an Apple Music sub? What I heard seemed a little like the processing used in BBC 4 podcasts. I don't know what they do but it is quite distinctive.

[stubbsonic]

I'm unclear about the relationship between Spacial Audio and Dolby Atmos. Also, is this a codec situation (i.e., encoded during mastering, decode with special software and special headphones)?

[Rick Cornish]

I'm unclear about the relationship between Spacial Audio and Dolby Atmos. Also, is this a codec situation (i.e., encoded during mastering, decode with special software and special headphones)?

Here's some info I found: https://www.cnet.com/how-to/spatial-aud ... wwdc-2021/

The implication is that content will need to be processed through Dolby Atmos (or possibly Sony's 360 Reality Audio at some point in the future) in order for the listener to experience the "Spatial Audio" effect.

Let me know if you find out any more on the content development side.

[dix]

I'm unclear about the relationship between Spacial Audio and Dolby Atmos. Also, is this a codec situation (i.e., encoded during mastering, decode with special software and special headphones)?

It doesn't help that both Dolby's cinema spatial engine that's been in use for years, and binaural headphone version of Spacial Audio are both called "Atmos", but that's obviously deliberate.

I've never mixed in cinema Atmos, which can be scaled (yes, encoded) from 64 physical speakers to two from the same master audio file (a .DAMF), but I've kept an eye on the technology. The idea of Atmos Spacial Audio as a standard for music delivery (for headphones) always seemed like a passing fad, so I'm not up to speed on its particular particulars, but the workflow for both flavors (physical and virtual channels) are ostensibly identical.

Here's an article from last year that goes over basic concepts, but I'd love to learn more since I don't know beans and apparently Dolby Atmos ain't going away soon.
https://www.pro-tools-expert.com/home-p ... ment-r57h5

[Rick Cornish]

Here’s something on the Dolby site with a nice video

https://www.dolby.com/technologies/dolby-atmos/


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[dix]

A point worth noting, and that I keep forgetting, is that “spacial audio”, as defined by Apple, simply means audio sources stay put when you turn your head. A feature you get with Apple AirPods etc. Atmos is about surround sound, and can be experienced with or without spacial audio. …sort of a “duh” fact I know, but may be worth reminding

[Rick Cornish]

A point worth noting, and that I keep forgetting, is that “spacial audio”, as defined by Apple, simply means audio sources stay put when you turn your head. A feature you get with Apple AirPods etc. Atmos is about surround sound, and can be experienced with or without spacial audio. …sort of a “duh” fact I know, but may be worth reminding

Dix... this is from the CNet article I referenced above (bolding is mine):
"Spatial audio is Apple's term for a collection of audio technologies that bring 360-degree effects to video calls, movies and specially remixed music. Apple first introduced spatial audio on its AirPods Pro earbuds last year, and the company is now expanding the capabilities of other devices in the range.

While the technology that will power FaceTime calls is different, the spatial audio portion of Apple Music is Dolby Atmos Music. Dolby Atmos Music is one of two competing formats for providing surround and height effects in music -- the other is Sony's 360 Reality Audio. Apple hasn't made any pronouncements about Sony yet; Apple Music supports only Atmos for the moment.

"Listening to a song in Dolby Atmos is like magic," said Oliver Schusser, Apple's vice president of Apple Music and Beats, in a press release in May. "The music comes from all around you and sounds incredible."

The one thing that separates spatial audio on Apple Music from other audio technologies is the ability for the headphones to track where your head is in space, which helps with immersion. At CNET we've tried countless technologies that attempt to create surround from stereo headphones -- Dolby Headphone, DTS Headphone:X and so on -- but the effect disappears as soon as you move your head. In real life we are able to move our ears to help locate where a sound is coming from, especially behind us, so if you want to believe that you're in a 3D audio space, head tracking is essential.

In the case of the AirPods Pro and AirPods Max, the headphones have an onboard accelerometer which helps audio stay in place when you move around."

[CharlzS]

"Listening to a song in Dolby Atmos is like magic," said Oliver Schusser, Apple's vice president of Apple Music and Beats, in a press release in May. "The music comes from all around you and sounds incredible."

Oh no, I thought we were done with magic.