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Post by Boomzilla on Aug 9, 2021 22:13:16 GMT -5
So Apple has announced a proprietary version of Dolby Atmos that they’re calling “Spatial Audio.” As of yet, I know nothing of it but the name.
I have read, though, that it works with your existing speakers (no additional amplifier channels or speakers required) and even works with headphones.
I’m curious.
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Post by AudioHTIT on Aug 9, 2021 23:52:16 GMT -5
So Apple has announced a proprietary version of Dolby Atmos that they’re calling “Spatial Audio.” As of yet, I know nothing of it but the name. I have read, though, that it works with your existing speakers (no additional amplifier channels or speakers required) and even works with headphones. I’m curious. I listen to it regularly through my 7.2.4 Atmos system (the Apple Spacial material triggers the RMC-1 into Atmos), I have also listened briefly with AirPod Pros. I think it sounds very good, in fact the best of any of the attempts to expand music into the listening space — DynaQuad, Quad (SQ, QS, CD-4), and previous Dolby Digital codecs including the DSU. The closest thing to it is SACD, DVD-A or Blu-ray audio, but they don’t have heights. I can’t pick a poll choice however as I just think “CD” is a different experience, sometimes better, sometimes worse, but it’s stereo — Apples and Pomegranates. It is also (to the best of my knowledge) not lossless — unlike the rest of Apple’s catalog that was recently upgraded. So put me down as — I like it, I listen to it. We’ve talked about it in this thread apple-music-lossless-spatial-amazon |
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Post by Boomzilla on Aug 10, 2021 9:42:48 GMT -5
So does your processor need to hav the Dolby Atmos codec for SA to work at all, or will it work with analog stereo amps?
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Post by AudioHTIT on Aug 10, 2021 10:16:01 GMT -5
So does your processor need to hav the Dolby Atmos codec for SA to work at all, or will it work with analog stereo amps? While it does seem possible to listen to spatial audio with just two speakers, they and the system driving them need to be what I’d call ‘Atmos capable’. For example a pair of HomePods by themself can’t do it, but HomePods coupled to an TV can. The document below explains what it takes from Apple devices. I’m not sure if any system without at least one Apple device can yet produce Spatial audio, for instance with my system, my spatial music source is TV, though the rest is non-Apple. support.apple.com/en-us/HT212182 |
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KeithL
Administrator 
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Post by KeithL on Aug 10, 2021 10:34:42 GMT -5
Here's a link to the description in the original press release...
And here's an article that describes it in more detail... As I understand it, what "Spatial Audio" does is to use input from things like the accelerometer to "simulate a live listening experience". Apple is using the accelerometers in their AirPods and some of their other products to inform audio processing... They are tracking the motion of your head, then processing the audio in such a way that, when you rotate your head, the sound field rotates in relation to your head... So, let's assume you're listening to a concert, and the lead singer sounds like he's in the front of the room... With normal earbuds or headphones it would always sound like the singer was several feet directly in front of you, regardless of which way you were facing. If you turn your head, the sound field image, which is solely determined by the content and the speakers in the headphones or ear buds, "follows the direction you're facing".
But, with Apple's technology, when you rotate your head, the processor detects that motion, and adjusts the sound field, so the singer still sounds like he's in the same location in the room... So, if you rotate your head to the left, the processor moves his image in the sound field to the right by an equivalent amount, so his voice seems to be coming from the same direction...
So, if you were listening to that singer while walking around the room, and possibly turning in various directions, it would SOUND like the singer was standing in one place in the room....
This would more accurately represent what you would hear if you were actually at the performance... (And you can certainly see how it would make a phone conversation seem "more natural" and "more like you were talking to an actual person".)
However, to answer your question, from their description this technology is device specific... It relies on sensors like accelerometers in the specific Apple device that's doing it to track your head motion... And, also from their description, it works with "both ordinary content and Dolby Atmos content". (I would assume that it probably works with other sorts of surround sound content as well...)
(This sounds very much like an Apple-proprietary version of what the Smyth Realiser is said to do... ) It's also possible that they've also included other processing to simply "make other content sound more 3D" - but I haven't seen that specifically mentioned. I also see no reason why it wouldn't work with content that had been artificially upmixed from stereo into surround using the DSU... [added 12:40 PM] I stand corrected...
According to that last link Apple's "Spatial Audio" does do more processing besides "dynamic head tracking"... which still isn't available on Apple Music for now.
(They say: "spatial audio with dynamic head tracking is coming to Apple Music in the fall".) And, no, I have no interest in Apple products, or in yet another way to synthesize phony surround sound.
So does your processor need to hav the Dolby Atmos codec for SA to work at all, or will it work with analog stereo amps? |
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DYohn
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Post by DYohn on Aug 10, 2021 10:49:44 GMT -5
Where's the "Haven't heard it, don't intend to" selection on this poll?  |
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Post by marcl on Aug 10, 2021 13:15:11 GMT -5
Where's the "Haven't heard it, don't intend to" selection on this poll? I'm in the "Wasn't going to, but oh well it's free for three months so what the heck? Now I'll spend the afternoon trying to get it to work and find something I want to listen to." .... camp So ... works fine on ATV4K and plays Atmos. On my Win10 PC I have Dolby Access installed and the demos from it play Atmos on my XMC-2 just fine. Now I'm playing Spatial from iTunes and it shows up as DDSurround DDTrueHD7.1 so I don't think Atmos is being triggered. Same result using the Apple Music web app. As for how it sounds? Certainly great for background listening. What I want to do is listen to the Apple stream of some of my benchmark recordings that I have in 96/24 from known sources. It may be lossless after it leaves Apple's house, but we have no real idea what source files Apple has been given, and whether they have been pre-processed in any way. |
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Post by Boomzilla on Aug 10, 2021 13:15:23 GMT -5
OK - I've done some more reading, but still have a few questions...
1. The encoding of Spatial Audio (SA) is done at the source end by Apple. It's done with their proprietary variant of Dolby Atmos. Therefore, somewhere in the playback chain, you need an Apple device with their proprietary Apple SA decoder to "unpack" the virtual space encoded on the recording. This brings up my first question - Does the decoding step have to be done in hardware (aka Apple TV, Dolby-Atmos compatible AVR, or other device), or can the decoding be done in software (iTunes on a Mac, for example)?
2. The decoding of SA can be done with something like 32 channels if they're available (and if that many were encoded on the SA source bitstream). How does the decoder know how many channels are available for playback? What happens to the "unavailable" playback channels? Is that data discarded, or is synthesized into the down-mix for 2, 5, 7 or however many channels ARE available?
3. What percentage of the SA effects are lost at each reduction in playback channels? The SA codec is apparently intended for even 2.0 headphone listening, so obviously some of the virtual location information is still in the analog stereo output from the (multichannel) SA original.
Thanks - Boom
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Post by AudioHTIT on Aug 10, 2021 18:06:05 GMT -5
OK - I've done some more reading, but still have a few questions... 1. The encoding of Spatial Audio (SA) is done at the source end by Apple. It's done with their proprietary variant of Dolby Atmos. Therefore, somewhere in the playback chain, you need an Apple device with their proprietary Apple SA decoder to "unpack" the virtual space encoded on the recording. This brings up my first question - Does the decoding step have to be done in hardware (aka Apple TV, Dolby-Atmos compatible AVR, or other device), or can the decoding be done in software (iTunes on a Mac, for example)? 2. The decoding of SA can be done with something like 32 channels if they're available (and if that many were encoded on the SA source bitstream). How does the decoder know how many channels are available for playback? What happens to the "unavailable" playback channels? Is that data discarded, or is synthesized into the down-mix for 2, 5, 7 or however many channels ARE available?3. What percentage of the SA effects are lost at each reduction in playback channels? The SA codec is apparently intended for even 2.0 headphone listening, so obviously some of the virtual location information is still in the analog stereo output from the (multichannel) SA original. Thanks - Boom Pretty tough questions, here's my best shot. 1) The document I linked above tells you how to do it with a Mac, latest OS and Music App (we don't call it iTunes anymore 😊), but it also requires specific headphones or speakers, so I don't think you can say Hardware or Software, it seems to be both. Further, only specific later model Macs can do Atmos, my 2018 minis can't. 2) Really I don't know, but in the case of TV the stream is decoded to PCM & Dolby MAT, there is no 'bitstream' option to let your processor do it, but it does tell TV what it's channel config is. There is a limitation on the max number of channels either TV or MAT can support, I don't remember if it's 7.1.6, 9.1.6, 16 total, or exactly what, but data for Atmos is normally not discarded so I doubt that's the case. IMO TV is the best source for Spatial -- you can go on to an Atmos system or directly to AirPod Pros which sounded pretty good for the brief test I gave them. 3) 🤷♂️ No clue ... seems pretty academic. |
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Post by Boomzilla on Aug 10, 2021 21:48:49 GMT -5
Well, if new hardware is required for the SA codec to work at all, then it doesn't matter how impressive the effects are - Spatial Audio is DOA because the vast majority of consumers are NOT going to buy new Apple hardware just to have SA
Further, SA works ONLY with headphones, so the majority of listeners won't care at all.
You'd think that a company the size of Apple would do enough market research to realize that what they were planning wouldn't succeed at all BEFORE spending the R&D budget on such a boondoggle! But apparently not...
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Post by AudioHTIT on Aug 11, 2021 0:58:53 GMT -5
Well, if new hardware is required for the SA codec to work at all, then it doesn't matter how impressive the effects are - Spatial Audio is DOA because the vast majority of consumers are NOT going to buy new Apple hardware just to have SA Further, SA works ONLY with headphones, so the majority of listeners won't care at all. You'd think that a company the size of Apple would do enough market research to realize that what they were planning wouldn't succeed at all BEFORE spending the R&D budget on such a boondoggle! But apparently not... While it may be doa for you (and I respect that opinion as I also get annoyed by proprietary solutions), I think there are a lot of Atmos systems with TVs in them that are enjoying SA now, and even more iPhone / AirPod users who just think it’s cool. I’ll say it influenced me into getting an Apple One family subscription, though the Lossless content was the primary reason, and we already used most of the other One services anyway. But that’s what they’re looking for, that extra something to get you to subscribe. You could be right, I wouldn’t expect most traditional two channels guys to be jumping on it; I think it will depend on content continuing to be released that’s appropriate for the genre, if that dries up it’s dead. |
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