Stereo Sound vs. Spatial Sound

In the past few decades, stereo sound has been widely used in almost everything ranging from music recordings to live TV broadcasts. But like all other technology, stereo sound has its limits. And now with the imminent rise of augmented reality, the limitations of stereo are becoming really apparent.

Imagine a bird flying over your head in real life. Based on the way we perceive sound, you will be able to tell from which direction and at what distance the bird is flying. But when the sound of the same bird is recorded in the stereo format, we’re lost. With stereo audio it's only possible to determine the location of a sound on a horizontal plane, anywhere between left and right. But spatial audio, on the other hand, provides a completely immersive experience by mimicking the way we perceive audio in real life.

Spatial audio formats make it not only possible to place sounds in front of a listener on the horizontal plane, but also behind, underneath and above. It basically allows us to place sounds anywhere in a 3D environment.

Spatial audio for AR is a combination of object-based sound sources and binaural rendering that allows sounds to come from all directions while keeping the effects of distance intact. This means that in AR, when a visual object interacts with the environment or when you interact with a visual element, you’ll feel as if you’re interacting with the real thing based on the sound it produces. Spatial audio enhances that interaction by adding realistic 3D audio cues.

Using spatial sound in AR not only allows us to distinguish sounds from one another based on their pitch, loudness, location, and timbre, but also reproduces the spatial audio cues one perceives in real life. This results in an experience that is incredibly close to the real thing. When it comes down to the directional quality and benefits, spatial audio definitely beats stereo audio for AR.

Adding spatial sound to an AR experience not only makes it feel more real, it also improves the narrative dramatically. Without implementing spatial audio in AR, the user can easily lose track of where they should look next in an interactive experience. This results in decreased immersion. Spatial awareness breaks down and he or she might not follow the narrative anymore. Eventually the quality of the experience can decrease drastically.

Using spatial audio in an AR experience increases the narrative by adding spatial audio cues to direct the user, creating a more immersive experience. Spatial audio in AR opens up a world of possibilities for not only interactive games but for multimedia and films as well. Take a minute and imagine having AR objects all around you when playing a game but without any spatial audio. It’ll be near impossible to determine where the sound, and thus the object, is originating from.

The team behind Shanghai-based Directive Games are one of the few that have already taken advantage of the possibilities of spatial audio in AR. They introduced a new tank battle game at Apple's event last year. The game was being played on a tabletop with a futuristic virtual battlefield.

According to their CEO Atli Mar, you are not just controlling the game, you are in the game. The closer you get to the game, the louder the sound will be and if anything comes between you and the game the sound will subside much like in reality!

This game is just one of the few examples of the many games that will soon be out on the Apple and Google Play Store. So if you want to create relevant AR and VR productions then Spatial Audio is something that you just can’t overlook moving forward.

Want to know more about the possibilities of spatial sound in AR or VR? Reach out to me.

Loïs van Ruijven is Innovation Producer at Amp.Amsterdam