What is the Ambisonics format?

By Jakub Wasilewski

Nowadays the entertainment industry is more and more interested in immersive experiences when it comes to movies, video games and music. Along with already quite common 360 degree videos, there is also a growing demand for 3D audio. Surround systems like 5.1, 7.1 or cinematic 22.2 can surely deliver impressive effects, but none of them is an actual full spatial audio system. Mostly because once sources had been recorded, there is no way to change their positions freely.

​In order to obtain a real spatial audio, an entirely different approach is needed. An approach that should not perceive sound as list of spatially speaker-fixed sources, but as a whole soundfield instead. It is where an Ambisonics technique comes in handy. But before explaining what it actually is, let me begin with a quick overview of the Ambisonics.

​At the same time when the music audience was thrilled for the first time with “The Dark Side Of The Moon”, an Ambisonics idea has been conceived by Michael Gerzon from the University of Oxford. He realised, that using three figure-of-eight microphones and additional omnidirectional one, he can make a soundfield recording that can be expressed as four speaker-independent channels, the so called B-Format. It allows to store soundfield information in four channels and decode it later into specific speaker setup.

​As you can probably imagine, representing a whole soundfield using only four channels is not optimal. Spatial audio resolution is not very impressive when using a B-Format which is only 1st order of Ambisonics, In the 1970s It was difficult to achieve higher audio resolution due to the level of technical advancements at that time. Despite the fact that the Ambisonics technique was grounded on solid technical and mathematical foundation, it has not gained much attention or commercial success. 

In order to obtain higher orders of Ambisonics, which provides better soundfield representation and spatial resolution, a dense microphone array and advanced signal processing algorithms are needed. Both of these advancements are the cornerstones of the new recording system developed by ​ZYLIA.

ZYLIA 3rd order Ambisonics microphone

Fig. ​ZYLIA ZM-1 - a 3rd order Ambisonics microphone.

The ZYLIA ZM-1 microphone array is capable of recording sound in the 3rd order Ambisonics format. Recording in such format will be soon very relevant due to the recent announcements by Google and Facebook to add support for higher order Ambisonics playback in their players. Soon it will be possible to enjoy amazing spatial audio recordings on any web-enabled device. 

You need ambisonics microphone? Just try ZYLIA!