What is Spatial Audio and What Does it Have To Do With Binaural Audio?

By _Ceva's Experts blog

February 20, 2023

At this point, you’ve probably heard a bit about spatial audio from all over, but what is spatial audio exactly? What is this big feature that Google, Apple, and Samsung are all including in their products? And is it the same thing as Dolby Atmos? This post will go into detail about what spatial audio is and why we should care. However, if watching something is more your speed, check out our webinar on the topic.

History of Audio

When we’re not using headphones or earbuds, we’re listening to sound in 3 dimensions. It comes from every direction (above, below, to the right, left, behind, in front, and everything in between), and our brains can decipher these sounds to determine direction.

Technology to emulate this natural experience anywhere has been a pursuit for well over a century. In 1881, a French engineer named Clement Ader invented the Théâtrophone, which used 80 telephone transmitters connected across the stage of the Paris Opera. These transmitters created a binaural stereoscopic sound (a method of recording sound with two microphones arranged to replicate the 3D stereo sound one perceives in real life). With this, appreciators of the opera could listen from as far away as two kilometers.

In World War I and the early part of World War II, acoustics played a large part in determining the direction of aircraft. Each country had their own unique ways of picking up and amplifying noise to help hear the plane engines and determine their direction. Looking back they look a bit comical, but it’s clear audio was a key war technology.

About 30 years later, in 1972, Neumann released their first commercial binaural recording system, allowing the replication of spatial sound to be simplified and consistent across various applications. Technology and methods have since improved, including a newer technique of using arrays instead of just two distinct microphones to get a more detailed recording of a given space.

Today, advanced audio techniques are being integrated in all sorts of audio applications (from music to gaming) on all sorts of devices like sound bars, headphones, TWS earbuds, automobiles, and XR devices.

Spatial Audio Family Tree

The way we listen to audio has also changed through the years. It’s started with mono output like you’d hear from a radio. All of the sound came from one source. But then sound evolved into using more speakers to give listeners a more engaging and encompassing sound experience.

The earliest form of this was stereo sound, with two speakers, then into quad sound with 4 speakers. This advanced to surround sound, with 5.1, 7.1 (where there are 5 and 7 speakers, respectively, and a single subwoofer for lower frequencies), and large speaker arrays (way more than 7) for more spatial output.

While 5.1 and 7.1 surround sound systems emulated sound around you, it was only really in a single plane around you as those speakers surround you at about the same height. Dolby Atmos has come into the audio space to give audio cues of sounds above and below you, creating a more immersive experience.

So what IS Spatial Audio?

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