What is volumetric audio recording?

Volumetric audio recording is a technique that captures sound in a way that mimics how our ears perceive sound in the real world. It captures not only the level of sound (loudness), but also the location and movement of sound sources in a room or environment. This allows for a more immersive listening experience, as the listener can perceive the sounds as if they were actually in the room where the recording was made.

There are a few different methods used to achieve volumetric audio recording. One of them is to use a grid of multiple Ambisonics microphone arrays to capture sound from different angles and positions. Additionally, the 6 degrees of freedom (6DoF) higher-order Ambisonics (HOA) rendering approach to volumetric audio recording allows the listener to move freely around the recorded space, experiencing the sound as if they were actually present in the environment.

You can imagine that a single Ambisonics recording is like a 360 camera but for sound. It captures the sound around the listener, and the Ambisonics format allows for rotation or selection of a particular direction. Extended to multi-point Ambisonics, you can achieve teleportation from one position to another. However, by using a dedicated renderer like the ZYLIA 6DoF renderer plugin, it is possible to create an infinitive number of listening points within a given space, e.g., live concert. Interpolation and rendering of volumetric sound are possible even if we have a limited number of Ambisonics microphones.

The six degrees of freedom refer to the three linear (x, y, z) and three angular (pitch, yaw, roll) movements that can be made in a 3D space. In the context of volumetric audio recording, these movements correspond to the listener's position and orientation in the space and the position and movement of sound sources.
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The resulting audio can be played back through surround sound systems or virtual reality technology to create a sense of immersion and realism.

Volumetric audio recording and 6dof rendering approach is used in a variety of applications, such as virtual reality, gaming, film, television and interactive audio installations, where the listener's movement and orientation play an important role in the experience. It also allows for a more immersive and realistic listening experience, as the listener can move around the space and hear the sound change accordingly, just as they would in the real world.