WWDC 2021 saw Apple announce iOS 15, macOS Monterey and a host of AirPods upgrades, but it seemingly held off announcing a particular audio feature: one that could add Dolby Atmos-style surround sound to any piece of media.
As spotted by reddit user u/hzfan, the current iOS 15 developer beta version includes a new “Spatialize Stereo” setting in Control Center. This apparently recreates the 360-degree sound effect of Apple Music’s spatial audio, even if the track wasn’t originally mastered for Atmos; this was previously a requirement.
Further investigation by 9to5Mac found that not only Spatialize Stereo available on macOS Monterey as well, but the fetaure reportedly works for both music and video. In the latter’s case that includes Apple’s 3D head-tracking capabilities, too. You’ll need the AirPods Pro or AirPods Max for this particular function, but, again, it will apparently work without the video having Atmos support.
It sounds like the Spatialize Stereo option essentially just uses upmixing, a long-established technique for enhancing stereo and even mono audio up to 5.1 surround sound. But while the concept isn’t new, this feature could provide a major boost to how you can enjoy music and video on your Mac or iPhone.
The main issue with Apple’s spatial audio tech is a relative lack of supportive content. For both video and Apple Music content, the song, TV episode or movie must be encoded for Atmos. While not particularly rare, such encoding is far from the norm. When spatial audio launched for Apple Music on June 7, only thousands of the service’s 75 million-strong song library were available in the Atmos format.
An easy toggle setting that spoofs the effect, but can apply itself to any track or video, has obvious benefits. u/hzfan said that they’d “pick Atmos spatial audio mixes over Spatialized Stereo every time,” so it’s safe to say the latter’s 3D effect might not be as convincing as true Atmos content. But hey, if it works well enough, it could be worth using until more content becomes available with Dolby mastering.
You’ll probably be able to try Spatialize Stereo for yourself come July, when both iOS 15 and macOS Monterey enter public beta ahead of their respective full releases this fall.