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

In iOS 15 and macOS Monterey betas, Apple has quietly included a new audio feature called "Spatialize Stereo" that takes any non-Dolby stereo mix and creates a virtual spatial audio environment out of it.

spatialize stereo 1
The addition was first discovered by a Reddit user, who had this to say about it:

I assumed that if they ever did this it would warrant at the very least a mention in a Keynote, but unless I completely missed it today I don't think they said anything about it!

The greatest thing about this is that it supports EVERY audio track. Sure I'd pick Atmos Spatial Audio mixes over Spatialized Stereo every time, but for the moment there are only a dozen or so options for Atmos available on Apple Music, so this is such an amazing feature to have!

It's worth reiterating that Spatialize Stereo is different from Spatial Audio, which Apple brought to Apple Music subscribers earlier this week. Spatial Audio with support for Dolby Atmos creates a three-dimensional experience by moving sound all around you.

Spatialize Stereo meanwhile appears to be Apple's attempt to simulate the effect of having sound coming at you from different directions in a virtual environment. It doesn't utilize Dolby Atmos, but on the other hand it works with basically any content, although you do need AirPods Pro or AirPods Max headphones to access it. Here's how it works in the latest ‌iOS 15‌ beta:

  1. Connect your ‌AirPods Pro‌ or ‌AirPods Max‌ to your iPhone or iPad.
  2. Play some non-Dolby audio content on your iOS device.
  3. Bring up the Control Center.
  4. Long press on the volume slider.
  5. Tap the Spatialize Stereo button to enable it.

spatialize stereo
The same option can be found in ‌macOS Monterey‌ in the Control Center's Sound pane. In terms of sound quality, your mileage may vary, but it at least allows users to enjoy some of the benefits of spatialized sound on anything they listen to, and not just content that officially supports Spatial Audio. If you've been able to compare the two different modes, let us know what you think in the comments.

Related Roundups: iOS 15, iPadOS 15
Related Forum: iOS 15

Top Rated Comments

ElliotF Avatar
8 months ago
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.
Score: 20 Votes (Like | Disagree)
xalea Avatar
8 months ago
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.
Score: 18 Votes (Like | Disagree)
haruhiko Avatar
8 months ago
My 1997 Winamp memory is coming back.
That surround sound plug-in turned every MP3 into broken surround music ?

“Winamp… it really whips the llama’s ass”
Score: 16 Votes (Like | Disagree)
IceStormNG Avatar
8 months ago

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.
You're not alone. The thing is: Those headphones don't do real surround even if the the track is a native surround file. You just have left and right. What they do are audio effects that try to mimic the timing difference depending on the sound origin relative to your head.
For that purpose, a "reference head" is taken and measurements are based on that. The more your head differs from that, the worse it works. Our ears are all slightly different and our brain is used to our own ears.

In the end, Spatial Audio is just a fancy name for "virtual surround" which exists since many years. It will and can never be on the same level as true surround with speakers in a room. It will always cause some distortion to the track.
Also: Some headphones are better than others to playback virtual surround.
Score: 15 Votes (Like | Disagree)
ian87w Avatar
8 months ago
Err... Why? Putting on fake effects on regular audio files never sound good to me.
Score: 12 Votes (Like | Disagree)
RamGuy Avatar
8 months ago

In the end, Spatial Audio is just a fancy name for "virtual surround" which exists since many years. It will and can never be on the same level as true surround with speakers in a room. It will always cause some distortion to the track.
Also: Some headphones are better than others to playback virtual surround.
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".
Score: 10 Votes (Like | Disagree)

Related Stories

Spatial Audio Netflix Feature 2

Netflix Rolling Out Spatial Audio Support

Wednesday August 18, 2021 1:29 pm PDT by
Netflix is rolling out support for Spatial Audio on the iPhone and the iPad, based on reports shared by MacRumors readers and on Reddit. A Netflix spokesperson also confirmed to MacRumors that the rollout is underway. When playing compatible content in Netflix, Spatial Audio will be available as an option in the Control Center on iPhone and iPad for those running iOS 14 and iOS 15....
iPhone Hi Fi Apple Music Feature

Apple Music's New Spatial Audio Feature Launches Today

Monday June 7, 2021 10:43 am PDT by
Spatial Audio, powered by Dolby Atmos for Apple Music is officially launching today, Apple announced during its WWDC keynote. Announced earlier last month, Spatial Audio provides a more immersive music experience for Apple Music subscribers at no additional cost. Spatial Audio will initially be available to thousands of songs on Apple Music, with the selection growing more in the future. The ...
maxresdefault

Apple's Zane Lowe Introduces Apple Music Spatial Audio

Tuesday June 8, 2021 9:40 am PDT by
Apple Music over the weekend highlighted a Spatial Audio-focused "special event," and it turns out that event is a discussion between Apple's Zane Lowe and music producers No I.D., Sylvia Massy, and Manny Marroquin. The Apple Music event can be watched in the Apple Music app or on YouTube, and it features Lowe and the music producers discussing the evolution of music and the sound...
maxresdefault

Apple and Billie Eilish Collaborate on Short Film Promoting Spatial Audio

Thursday August 12, 2021 6:52 am PDT by
Apple has teamed up with singer Billie Eilish on a new short film to promote Apple Music's recently launched Spatial Audio feature. The 90-second video, created by Apple Music in close collaboration with Eilish, mashes up the songs "Getting Older" and "GOLDWING" from the artist's latest album "Happier Than Ever." Eilish is seen singing in front of a vanity mirror, and as the song...
maxresdefault

Spatial Audio on Apple Music Promoted in New 'Beyond Stereo' Ad

Monday June 14, 2021 6:43 am PDT by
Just days after the launch of Spatial Audio on Apple Music, Apple has promoted the feature with a new "Beyond Stereo" ad set to "Mystery Lady" by Masego and Don Toliver. Spatial Audio, based on Dolby Atmos, is an immersive surround sound audio format that enables musicians to mix music so it sounds like the instruments are all around you in space. Thousands of Apple Music songs are available ...
homepod feature purple

HomePod Will Support Spatial Audio for Apple Music, But Not Lossless Audio

Monday May 17, 2021 1:34 pm PDT by
Apple Music will be gaining support for two new audio formats in June, including Spatial Audio and Lossless Audio, but MacRumors has received confirmation that the HomePod and HomePod mini will not support Lossless Audio. Apple's website does indicate that the HomePod will support Spatial Audio, but it's unclear if this includes the HomePod mini. Spatial Audio, based on Dolby Atmos, is an ...
spatial audio iphone 12 pro

Eddy Cue Says Spatial Audio on Apple Music is Equivalent to Watching HD Television for First Time

Tuesday June 8, 2021 8:00 am PDT by
Apple Music's new Spatial Audio feature started rolling out on Monday evening and officially launches today, and to mark the occasion, Apple's services chief Eddy Cue and Apple Music radio host Zane Lowe shared some thoughts. Spatial Audio, based on Dolby Atmos, is an immersive three-dimensional audio format that enables musicians to mix music so it sounds like the instruments are all around ...
apple music android listen now

Apple Music for Android Reportedly Won't Support Dolby Atmos

Tuesday May 18, 2021 2:55 am PDT by
Apple Music on Android devices will not include Dolby Atmos support when Apple launches Spatial Audio on the streaming service in June. That's the claim from MySmartPrice, which says it received confirmation from Apple India that the sound technology would not be crossing the divide between Apple and Android ecosystems. For anyone confused by all the audio nomenclature that's been bandied...

Popular Stories

maxresdefault

Review: M1 Max MacBook Pro After Three Months

Wednesday January 19, 2022 11:30 am PST by
It's now been a few months since the M1 Pro and M1 Max MacBook Pro models launched in October, and MacRumors video editor Dan Barbera has been using one of the new machines since they debuted. Over on the MacRumors YouTube channel, Dan has shared a three month review of his MacBook Pro to see how it has held up over time and how it's changed his workflow. Subscribe to the MacRumors YouTube ...
airpodsinear 1

AirPods Save Woman's Life With Feature Everyone Should Know

Friday January 21, 2022 2:13 am PST by
Apple's AirPods have been credited with saving a woman's life after a potentially fatal fall, People reports. When a 60-year-old florist in New Jersey tripped and hit her head in her studio, she lost consciousness and awoke heavily bleeding. With nobody around to call for help, she realized she had her AirPods in, and used a "Hey Siri" command to call 911. An operator was able to stay on the ...
iphone se 2020 top

New iPhone SE Likely to Launch in April Based on Production Timeframe

Wednesday January 19, 2022 6:44 am PST by
Apple suppliers will begin producing display panels for the third-generation iPhone SE this month, with final assembly of the device likely to start in March, according to information shared by display industry consultant Ross Young. Based on this production timeframe, Young believes the third-generation iPhone SE is likely to launch in the second half of April, or perhaps in early May at...
iphone 13 earpods

Apple to Stop Including EarPods With Every iPhone Sold in France From Next Week

Friday January 21, 2022 3:21 am PST by
Apple will no longer include EarPods with every iPhone sold in France, starting on January 24, according to a notice posted by a French carrier (via iGeneration). Apple was previously required to include EarPods in the box with the iPhone due to a French law that required every smartphone sold in the country to come with a "handsfree kit," but the law has now been changed in favor of reducing the ...
Spring 2022 Apple Products Feature

New iPad Air, Macs, and iPhone SE With 5G Likely to Be Announced at Apple Event This Spring

Thursday January 20, 2022 8:32 am PST by
Earlier this week, Bloomberg's Mark Gurman tweeted that Apple "will be holding a spring event" to announce a new iPhone SE and other hardware. In a recent edition of his newsletter, Gurman said the event is likely to occur in March or April. Gurman did not elaborate on what "other hardware" will be announced at Apple's purported spring event, but rumors suggest at least four products are...
appleeducation

Apple's US Education Store Now Requires Institution Verification to Buy Discounted Products

Wednesday January 19, 2022 2:22 am PST by
Apple is now requiring that customers in the United States verify that they're active students, teachers, or staff members at an educational institution in order to access education discounts on products. Previously, little verification was needed for customers to purchase products through Apple's education store in the United States. Apple's education stores offer models of the iPad and Mac ...
AirPods 3 New Firmware Feature

Apple Updates AirPods 3 Firmware to Version 4C170

Tuesday January 18, 2022 11:46 am PST by
Apple today released a new 4C170 firmware update for the AirPods 3, an update from the prior 4C165 that was made available in December. Apple does not offer details on what's included in new firmware updates for the AirPods‌, so we don't know what improvements or bug fixes the new firmware brings. There is no standard way to upgrade the ‌AirPods‌‌ software, but firmware is...
appleprivacyad cleaned

iOS 15 Patched Security Hole That Potentially Exposed Users' Private Apple ID Information to Third-Party Apps

Thursday January 20, 2022 3:32 am PST by
Apple patched two significant security vulnerabilities when it released iOS 15 that could have potentially exposed users' private Apple ID information and in-app search history to malicious third-party apps and allowed apps to override user Privacy preferences, Apple has revealed in a recent support document update. With most iOS, macOS, tvOS, and watchOS updates, Apple provides a list of...
apple watch series 7 aluminum colors yellowbg

Apple Watch Charging Bug Fixed in watchOS 8.4 Release Candidate

Thursday January 20, 2022 4:01 pm PST by
The watchOS 8.4 release candidate that was seeded to developers and beta testers this morning addresses an ongoing bug that could cause some Apple Watch chargers not to work properly with the Apple Watch. Back in December, we reported on a growing number of charging issues that Apple Watch Series 7 owners were facing. Since watchOS 8.3, there have been a number of complaints about...