'Spatialize Stereo' Feature in iOS 15 and macOS Monterey Simulates Spatial Audio for Non-Dolby Content

[SueperDrive]

One massive difference with "native" Dolby Atmos tracks on Apple Music is that the source has been mixed with Dolby Atmos in mind from the getgo.

Sure, you are virtualising when playing back on headphones as you only have two speakers. But comparing this to the age-old surround virtualisation we have had for years isn't fair.

If you are using a Windows PC and run old surround virtualisation tech like Dolby Headphones or Creative CMSS:3D that have existed for a very long time, you apply it to music from iTunes or whatever. You are taking a 2-channel source and apply algorithm/DSP, trying to map it to 7-channels, and that is then being played back and simulated by your 2-channel headphones.


With Dolby Atmos tracks on Apple Music, Apple receives new masters from the record labels where Dolby Atmos is already in the source. How much time and attention the labels and producers have put into their Dolby Atmos mixing will differ. But Apple is receiving source material directly with Dolby Atmos metadata attached.

There is no algorithm/DSP trying to redefine how this 2-channel source should be upsampled to 7-channels. The labels and producers themselves have worked directly and attached the metadata telling Dolby Atmos what should be played where within Dolby Atmos 360-degree sphere of sound.

Obviously, when being played back on a pair of 2-channel headphones, you are still faced with simulated playback. But the whole idea behind Dolby Atmos is to have a reference format used by the creators and throughout the entire playback chain. When using headphones supporting Dolby Atmos, the headphones are supposed to follow the Dolby Atmos spec and be capable of interpreting and handling the Dolby Atmos metadata. So even though it's still simulations, the source and the simulation being done are talking the same language, providing a much more cohesive and better experience overall. The source contains the metadata telling the headphones exactly where in this 360-degree sphere the audio is supposed to come from, and Dolby Atmos capable headphones are supposed to simulate this with decent precision. It's not pure guesswork like it was with things like Dolby Headphones etc., back in the day.


Dolby Atmos is not like your regular surround either. Dolby Atmos doesn't limit itself to the old static notion of 5-channel, 7-channel surround. With Atmos, you have this 360-degree sphere, and you can mix your playback to have sound coming from any point within this sphere. You can have up to a total of 128-channels per track. Even if you have 12-channels in your home theatre, a Dolby Atmos track will most likely contain metadata that exceeds the number of static channels you have in your setup. But if your home theatre supports Dolby Atmos, it should read this metadata and apply simulation using all the channels you have available to try to do whatever it can to achieve best the playback information contained in the metadata.

If it was just virtualisation there would be no need to have Dolby Atmos tracks on Apple Music. Apple could just implement the spaceilised setero feature and virtualise all the 2-channel tracks into "Spatial Audio".

Are you sure about that?

Dolby Atmos for Home Theater is not 360 degree. Only the Cinema version is capable of this. As home user you are getting a 5.1 or 7.1 track with metadata for the upper channels.

And I don't think that all of the available Dolby songs on Apple Music are really in Dolby Atmos as in 5.1 or 7.1 plus metadata. Thats because of two reasons:
1. there are very few Atmos Albums out there because the mixing is time demanding
2. when you switch the Dolby Spatial on or off in the settings during the playback, the change ist immediately. If this would be a separate track, there would be a buffer or loading time.
Thats why i think that this is just upmixed with dolby headphone like algorithm.

Only when the Feature will be available on Apple TV paired with a Dolby Atmos receiver, we will be able to se what the real soundtrack is.

 

[Zeke92]

A lot of folks used to listening to stereo will prefer stereo over anything else just because that’s what’s familiar to them. It’s expected, really. Some folks don’t like the Apple Pencil because it erases without flipping and the screen doesn’t feel like paper when they use it. Some folks don’t like touch screens because they’re used to the mouse.

Lol nice try but there technical issues with a lot of the Dolby Mixes. Some of the instrument sound muddled. The midrange sounds muted and vocals sound over processed with an echo. A lot of people’s objections are technical. We will have to wait and see but right now they are taking stereo mix’s and up mixing them to atoms just so that they could be put into our 2 ears with 2 air buds. It doesn’t make sense. A good stereo master is incredibly immersive.

 

[Unregistered 4U]

Lol nice try but there technical issues with a lot of the Dolby Mixes. Some of the instrument sound muddled. The midrange sounds muted and vocals sound over processed with an echo. A lot of people’s objections are technical. We will have to wait and see but right now they are taking stereo mix’s and up mixing them to atoms just so that they could be put into our 2 ears with 2 air buds. It doesn’t make sense. A good stereo master is incredibly immersive.

There are “technical issues” with the mono -> Stereo mixes, too. “The audio is separated in ways that were never intended! Why are certain drums going to different ears??” It can be described in any way someone likes, but what it comes down to is “I like stereo because that’s what I’ve heard it all my life and anything that sounds different is, by default, bad.”

 

[jeffmetanna]

For those of you who still think surround sound in stereo is a gimmick, please search for "binaural audio" on YouTube (or this link)and experience yourself. Make sure you wear a headphone for this.

 

[Zeke92]

There are “technical issues” with the mono -> Stereo mixes, too. “The audio is separated in ways that were never intended! Why are certain drums going to different ears??” It can be described in any way someone likes, but what it comes down to is “I like stereo because that’s what I’ve heard it all my life and anything that sounds different is, by default, bad.”

What No! My point being is that most of the tracks seems to be converted Dolby Atmos and they sound muddled in an unintended way. That’s technical. If the song was originally mastered in Dolby Atmos great that’s what I want to what. If not, I want to what the original recording And now that we are typing I think we agree for the most part. But these converted mixes sound flattened in a weird way

 

[Zeke92]

For those of you who still think surround sound in stereo is a gimmick, please search for "binaural audio" on YouTube (or this link)and experience yourself. Make sure you wear a headphone for this.

Wow that was actually pretty incredibly. I turned around in my office thinking something was happening behind me

 

[Mr. Awesome]

I discovered this yesterday listening to music with my AirPods on iOS 15. It's a super neat feature.

Me too! I discovered that Youtube seemed to be working with Spatial Audio suddenly, and I couldn’t tell how.

 

[Squillace]

For those of you who still think surround sound in stereo is a gimmick, please search for "binaural audio" on YouTube (or this link)and experience yourself. Make sure you wear a headphone for this.

Correction : surround sound in music is gimmick.
I know the barbershop audio for years and it still amazes me. But it's closer to a movie experience than a music one.

 

[srbNYC]

It is an option. Turn it on or turn it off. Voila.

Or perhaps we should BAN chunky peanut butter, because it's gross and wrong.

 

[srbNYC]

Am I the only one who finds that stereo sounds better than spatial audio? I played a song, then went into the music settings and switched it between “off” and “always on” as the track was playing and found stereo to be so much better. I’m using AirPods Pro btw.

I can't find that "always on" option. Is that only on Apple Music, or in the Music app itself?

 

[EntropyQ3]

As a music producer who spends a lot of time and effort mixing to get just the right stereo sound field and 'wall of sound,' putting this kind of crap on top of one of my tracks would make me cry. lol. Please don't dishonor the work of many audio engineers and technicians, mastering experts, etc. by applying this junk to their tracks.

While I respect this, headphones aren’t loudspeakers, and the lack of any crossfeed between the stereo channels, nor associated time delays and frequency response effects that are inherent in loudspeaker reproduction is present with headphones.
Dolby headphone(tm), and similar schemes try to adress this.
From the description, it is difficult to see if this is what the simulated ”spatial audio” tries to do or if it tries to simulate some kind of surround soundfield. If it’s the first - nice. If it’s the second - iffy, since the soundfield information just isn’t present in the recording and has to be faked in a general way. Which can’t succeed, really.

 

[EntropyQ3]

For those of you who still think surround sound in stereo is a gimmick, please search for "binaural audio" on YouTube (or this link)and experience yourself. Make sure you wear a headphone for this.

I’ve made binaural recordings. There is no better way to record and reproduce a soundfield.
That said, music is rarely ”a soundfield”. Typically you want to simulate (since most music isn’t recorded live) musicians playing in front of you. Even when you do record a live classical performance, binaural isn’t necessarily ideal, since it records the venue in its totality but without the visual cues that reinforce our focus and directionality.

 

[odHbo]

I really like the sound of Dolby Atmos Spacial Audio over traditional Stereo. It sounds more full and detail rich to me. Stereo was louder (which my ears also liked) and comfortably familiar. But this is like HD tv where people didn’t like the increased detail in the beginning until it took over. Now no one wants to go back to SD.

I’ve been in the ultra high end audio industry for over a decade now and the experience garnered from what I refer to as “the chase for audiophile sound” has been mostly a huge disappointment. Expensive equipment, tiny music library and the mass alienation of the general public.

The last time I was impressed by digital music was at the Meridian showroom in NYC listening to MQA on DSP8000 S2s, a pair of $80,000+ speakers. It was great, and what I recall as the best demo was hearing the atmospheric sound that came from Aretha Franklin’s R.E.S.P.E.C.T. having been originally recorded in a stairwell. MQA seemed promising but went no where as far as what Apple Music already has here. I have yet to hear anything as enveloping and rich as that Meridian demo until I heard The Weeknd’s “Blinding Lights” in Atmos on my APM and from my Apple TV on a Sonos Arc surround sound system.

Dolby Atmos audio looks to me as a solid foundation for NEW music and NEW remasters. Artists have to intentionally plan for it. Thanks to the big streaming companies, this sound will reach far more ears than MQA has and soon traditional stereo speakers will be replaced with 360 atmospheric speakers.

Whether you like it or not, I think a new world of “audiophile grade” will emerge from here and it will be made up of younger ears chasing the best way to listen to Atoms music rather than wanting tube amps and FLAC.

Amazon, Apple, Spotify and Tidal have little to no interest in FLAC, D2A converters, turntables and traditional audiophiles.

 

[CoronaOnTap]

I’m probably in the minority among the posters here when I say I like the Spatialize Stereo better than the plain old stereo. Not everything sounds better and definitely not a fan of the anchor point for music but I’m enjoying the virtualization better for most stereo music content.

 

[sflagel]

While I respect this, headphones aren’t loudspeakers, and the lack of any crossfeed between the stereo channels, nor associated time delays and frequency response effects that are inherent in loudspeaker reproduction is present with headphones.
Dolby headphone(tm), and similar schemes try to adress this.
From the description, it is difficult to see if this is what the simulated ”spatial audio” tries to do or if it tries to simulate some kind of surround soundfield. If it’s the first - nice. If it’s the second - iffy, since the soundfield information just isn’t present in the recording and has to be faked in a general way. Which can’t succeed, really.

I totally agree. If Spatial Audio had just simulated listening to speakers, it would have been great (i.e, only Spatial Audio). Instead, they added Atmos to Spatial Audio and now we have guitars floating above you from left to right in Tom Sawyer and Neal Peart's cymbals rights next to your right ear...

 

[Nuvi]

A lot of folks used to listening to stereo will prefer stereo over anything else just because that’s what’s familiar to them. It’s expected, really. Some folks don’t like the Apple Pencil because it erases without flipping and the screen doesn’t feel like paper when they use it. Some folks don’t like touch screens because they’re used to the mouse.

And people that hate a thing will always be more vocal than those that like or don’t care one way or the other.

You do understand that it seems many if not the most Apple Music “Dolby Atmos” mixes are “poorly done cost cutters” or just plain utter crap. This has nothing to do “what you are familiar with”. In matter of fact I’m very familiar with Dolby Atmos mixes. I work in media industry and I have had possibility of critically listening mixining sessions in IMAX and Dolby Atmos mixing theatres. So I’m used to surround sound and definitely prefer it over stereo. However, I hate crappy surround. Even more so, if something is recorded with an intention of producing a Stereo mix (microphones and placement etc. ) and then few years/decades later one decides to do a “cost effective” new surround mix and master from old material which in some cases seem to be at least partially flat master, you end up crappy sounding money grab. On the other had, you could be listening a mint lossless stereo mix… at least for me it’s lossless all the way for Music. Naturally there will be some epic “audio journeys” in the future but they will be the polar opposite of a “cost effective” additional revenue source.

 

[Zeke92]

You do understand that it seems many if not the most Apple Music “Dolby Atmos” mixes are “poorly done cost cutters” or just plain utter crap. This has nothing to do “what you are familiar with”. In matter of fact I’m very familiar with Dolby Atmos mixes. I work in media industry and I have had possibility of critically listening mixining sessions in IMAX and Dolby Atmos mixing theatres. So I’m used to surround sound and definitely prefer it over stereo. However, I hate crappy surround. Even more so, if something is recorded with an intention of producing a Stereo mix (microphones and placement etc. ) and then few years/decades later one decides to do a “cost effective” new surround mix and master from old material which in some cases seem to be at least partially flat master, you end up crappy sounding money grab. On the other had, you could be listening a mint lossless stereo mix… at least for me it’s lossless all the way for Music. Naturally there will be some epic “audio journeys” in the future but they will be the polar opposite of a “cost effective” additional revenue source.

Exactly what I tried to explain. Thank you for this.

 

[Unregistered 4U]

I’ve made binaural recordings. There is no better way to record and reproduce a soundfield.
That said, music is rarely ”a soundfield”. Typically you want to simulate (since most music isn’t recorded live) musicians playing in front of you. Even when you do record a live classical performance, binaural isn’t necessarily ideal, since it records the venue in its totality but without the visual cues that reinforce our focus and directionality.

Music is a soundfield, though, isn’t it? I mean, even if musicians are playing in front of you, they’re not all playing from the same point on stage, there’s audio coming from center left right and rebounding off of the surfaces around you. Artists and mixers sometimes even prefer one studio over another due to the room’s acoustics enhancing the audio, so it would appear that the soundfield is important, just not usually had an opportunity to be captured and delivered to consumers.

 

[Unregistered 4U]

What No! My point being is that most of the tracks seems to be converted Dolby Atmos and they sound muddled in an unintended way. That’s technical. If the song was originally mastered in Dolby Atmos great that’s what I want to what. If not, I want to what the original recording And now that we are typing I think we agree for the most part. But these converted mixes sound flattened in a weird way

Oh, you DID say “a lot of” and “most”. I was reading absolutes where there were none! So, there ARE a few where you prefer the Dolby Atmos mix?

You do understand that it seems many if not the most Apple Music “Dolby Atmos” mixes are “poorly done cost cutters” or just plain utter crap. This has nothing to do “what you are familiar with”. In matter of fact I’m very familiar with Dolby Atmos mixes. I work in media industry and I have had possibility of critically listening mixining sessions in IMAX and Dolby Atmos mixing theatres. So I’m used to surround sound and definitely prefer it over stereo.

So… you’re familiar with Dolby Atmos mixes. And, just by that, I would guess that you would be more accustomed to some of the variances that others feel are “wrong” just because they’re not the stereo they’re used to. Which Dolby Atmos mixes currently available would you say are the good ones?

 

[Khedron]

Why release a “fake” version alongside promoting the real thing as a revolution?

Seems to undermine the whole messaging.

Yeah you can subscribe to a streaming service that has access to specially produced versions of songs that capture an artist’s true vision… Or just tap this option that automatically does basically the same thing…

 

[MrTemple]

Err... Why? Putting on fake effects on regular audio files never sound good to me.

Same reason people use upscaling for video.

The monkeyed-with version has less fidelity, more artifacts, but appears higher resolution/quality to less discerning eyes.

TONS of people love things like that. Many find it horrible.

 

[Lazlow]

I haven't heard a single one of these Dolby Atmos tracks that sounds even remotely good in my APPs. All of them sound like awful demos. I'll test it out maybe one day when I get a Atmos-capable surround sound system in my living room, but for now, no ma'am.

 

[skitidetdu]

Am I the only one who finds that stereo sounds better than spatial audio? I played a song, then went into the music settings and switched it between “off” and “always on” as the track was playing and found stereo to be so much better. I’m using AirPods Pro btw.

It is almost like hit and miss depending on the track and the stereo mix.

 

[Ace of aces]

It looks like there is some Spotify and Tidal employees trashing Apple's Dolby Atmos and Spatial Audio in this forum ... 🤣🤣
Sorry for you guys ... it's been a nice ride so far !!

#jealousy

 

[ErikGrim]

I totally agree. If Spatial Audio had just simulated listening to speakers, it would have been great (i.e, only Spatial Audio). Instead, they added Atmos to Spatial Audio and now we have guitars floating above you from left to right in Tom Sawyer and Neal Peart's cymbals rights next to your right ear...

If you listen to the Zane Lowe chat, Manny Marroquin says that because this is a new format to mix in, mistakes WILL be made. You'd think engineers would have learnt from the mono to stereo transition, but no. Give engineers a new toy and they will abuse it. Take the ATMOS mix of R.E.M's Drive; you have the engineer that clearly had access to individually recorded drums and had the bright idea to place you in the middle of the drum kit. Terrible idea! No one wants to listen to music with a bright tom in your left ear and a deep tom in your right.

Once these mistakes have been made and pointed out you'll see less of this, and things like "wandering instruments". The best way of utilising 360º mixing is to simulate listening to a band in front of you, in a room. Subtly enhancing the sound stage with real life reflections (reverb), but keeping the main focus tight. Use the space for atmosphere as the name suggests.

Not to say that it can't be used for great effective mixing either. The Gambler's new mix is a delight. And almost all the pop and electronic music works a treat too.