All content in this course uses:

Spatial audio 

 is a specialized form of audio that creates a three-dimensional sound experience and is used extensively in XR applications. Spatial audio more accurately represents sounds in the real world and, more importantly, the user’s proximity to the sound’s source. This setup gives users a greater sense of presence in a scene.

In this tutorial, you will learn how to implement spatial audio in an application, including an example where spatial audio is used on a mesh in a 3D model viewer.

Traditionally, audio is captured and reproduced in two channels: this is known as 

. These channels are commonly assigned to the left and right playback devices, such as a set of earbuds or pair of left and right speakers, and offer distinct audio signals. This configuration can help generate a perception of sound directionality, but it falls short of achieving genuine spatial audio fidelity.

, on the other hand, uses sophisticated algorithms to consider both the position of the listener and the sound source, enabling it to replicate how the sound would behave in a particular environment. Spatial audio allows users to precisely identify the source of the audio in relation to their position in all directions, including whether the source is coming from in front of, behind, above, or below the listener.

Spatial audio gives user’s a greater sense of presence in applications. This sense of presence can aid in immersion for entertainment applications, but it can also be very useful in training and testing applications where it’s important to test a user’s ability to identify important audio cues they would experience in a real-world site.

In this tutorial, you’ll learn how to configure a project to use the Magic Leap Soundfield Plugin, apply spatial audio to an object, and review an example of spatial audio in use in a 3D model viewer.

Overview

Before you begin working through this tutorial, you should make sure your development environment is set up for Magic Leap 2 development and download the example prototype project.

If this is your first time developing in Unity for the Magic Leap 2, make sure you have your development environment configured properly using one of the following guided options: 

 from the Magic Leap 2 developer documentation.

This tutorial will guide you through the implementation of this feature in your own application using an example prototype. If you want to explore the code of the prototype yourself, download the 

Before you begin

Just like with any Magic Leap 2 project, the first step is to add the 

Now that your camera is configured, add a few simple objects to the scene, such as grabbable cubes that you can move around. Add Audio Source components to these objects and select an Audio Clip for those sources. For your convenience, we have provided a few simple sounds for you to experiment with. You may also want to enable 

 for testing purposes. Configure the Audio Source as you typically would for spatial audio by enabling 

If you tested your project now, you would have simple 3D audio that you would expect from a typical 3D project. You can even test audio in the Editor and get the same result by moving the Audio Sources around relative to the 

. You will hear the volume increase and decrease as the distance changes and the balance between left and right channels change when the source is moved from side to side relative to the

. In the example shown here, we have also added toggles for each source’s audio and labels to make testing a bit easier.

Basic 3D audio setup

The following setup instructions are also detailed in 

Magic Leap’s Soundfield Plugin for Unity documentation

, but the high-level steps are also outlined below. 

The Soundfield Plugin is located in the Unity Packages section of the Magic Leap Hub Package Manager. The Soundfield Plugin will be saved to the same 

 folder that was created when you downloaded the first set of Unity tools through the Magic Leap Hub Package Manager. You can see the file path by selecting the "Open Folder" button under the package name in ML Hub Package Manager.

Make note of this file path, as it is needed to install the package in Unity.

To install the Magic Leap Soundfield plugin from the Package Manager, select 

, navigate to the Soundfield Plugin location, then select the 

 file in the most up to date version folder. 

During the installation, a few warning dialogs may pop up to indicate that certain aspects of your spatializer are not configured yet — you’ll fix that next.

Once the Plugin is installed, all that remains is to enable it in your project. In the 

: If you are a Windows user and encounter errors when loading the Soundfield plugin, you may be missing the Visual Studio Redistributable C++ libraries on your machine. You can get the necessary libraries directly from 

With the Soundfield Plugin enabled, you can now add Magic Leap’s spatial audio to a scene. The Soundfield Plugin requires an additional component to be added to both the 

 GameObject as well as the audio listener located on the 

To enable the Soundfield spatial audio on your camera, add a MLListener component. 

The MLListener component allows you to customize the way that audio is perceived in your application. You can leave this component’s settings at their defaults for now, but if you want to customize the component, you can learn more about its properties in Magic Leap’s 

Once the basic Audio Sources are configured to your liking, add an MLPointSource component to the audio source GameObjects. These additional options will allow you to configure other, more nuanced sound properties for the audio for your environment, which you can learn much more about in 

Magic Leap’s documentation on this component.

, you will be able to visualize some of these properties in the Scene view.

 Distance properties are in real-world meters.

If you test your project now, the soundscape will feel more intuitive and realistic.

Magic Leap Spatialized audio setup

The Soundfield spatializer is incredibly powerful and we encourage you to explore some of its other features detailed in 

Magic Leap’s Soundfield Audio documentation

For example, Audio Sources with the Soundfield components applied to them will be obstructable by any object that has a collider attached to it. To test this, you could add another mesh to your scene and arrange it so that the mesh can be placed between the user and the Audio Source. Make sure to scale the mesh up so that it is a meaningful sound barrier. 


You can also visualize the sound during runtime using 

More things to try with the spatializer

Now that you know how to set up spatial audio, let’s check out an example of how this feature can be combined with other interactive functionality.

In this example, the user is using a 3D model viewer with hand tracking, and the audio emanating from the model is spatialized.

Spatial audio in context

In this tutorial, you learned how to implement spatialized audio on the Magic Leap 2 with the Soundfield plugin. You can learn more about spatialized audio with the following resources:

You may also want to learn more about out the other features highlighted in the example prototype:

Unity Version 2022.2