After completing the tutorial, you will have a solid understanding of how to use the Meta XR Audio SDK and will be equipped with the knowledge to continue developing your project and unlocking its full potential.

Ambisonics is a multichannel audio format that represents a 3D sound field. Think of it as a skybox for audio with the listener at the center. It is a computationally-efficient way to play a pre-rendered or live-recorded scene. The trade-off is that ambisonic sounds offer less spatial clarity and introduce more smearing than point-source sounds processed using a head-related transfer function (HRTF).

An HRTF describes how sound waves are filtered by the shape of a listener’s head, ears, and torso before reaching the eardrum. By applying HRTF processing to audio, point-source sounds can be rendered with precise spatial cues, making it possible for the listener to perceive the exact direction and distance of each sound in 3D space.

Use ambisonics for non-diegetic sounds such as music and ambiance.

Learning objectives:

Load and explore the Ambisonics Meta XR Audio SDK sample.

Create a scene utilizing Meta XR Audio SDK features.

Further modify and manipulate your scene.

Prerequisites

Before proceeding with this tutorial, complete the setup steps outlined in the following sections:

Set Up Unity for XR development to create a project with the necessary dependencies

Set up your device to configure and test your project on a headset

Unity ID: Create or log in to your Unity account

Headset scene preview available only on Windows

To preview a scene in a headset, you must use the Meta Quest Link app on a Windows machine to connect to the headset. To simulate the headset view on a macOS (ARM only) or Windows machine, install the Meta XR Simulator asset in your Unity project.

Install the Meta XR Audio SDK

In a web browser, go to Meta XR Audio SDK.

Click Add to My Asset.

In the Package Manager under the Window dropdown, select My Assets > Meta XR Audio SDK.

Click Install.

Import the samples

Navigate to the Meta XR Audio SDK in the Package Manager.

Under Samples, select Import to add new scenes and assets to the Unity Project folder.

Once imported, the sample content will appear at the following path within your project: Assets > Samples > Meta XR Audio SDK > version > Examples Scenes.

Load the scenes in the folder.

Note: The samples are meant for Play Mode only testing using typical WASD keys and mouse control.

View the scene

Note: If you are developing on macOS, you cannot preview the scene on a headset. Use Meta XR Simulator instead.

Connect your headset using Link and put it on.

Open the Quick Settings window by selecting the clock on the left side of the menu bar.

Open Settings, select System > Quest Link, and toggle Quest Link on.

Select Launch Quest Link to start Link on your development machine and on your headset.

In your Unity project, press Play(►) to run the app on your headset.

Open the Ambisonics sample scene and run it on your headset. You will find a yellow ball in the center of the plane. It is outputting the ambient sound of a pleasant park which fully envelops the scene.

Create a blank scene

To gain some hands-on experience, recreate the ambisonics sample from a blank scene. After that, follow guidance on how you can make your new scene even more dynamic and get even more experience with the Meta XR Audio SDK.

You can create your new scene alongside the provided samples within the Assets > Samples > Example Scenes folder. Right click in the Project window and select Create > Scene > Scene.

Give your new scene a name, like Testing.

Recreate the ambisonics scene

Every new scene includes some default GameObjects:

Main Camera The default camera contained in all new Unity projects. In the next step you will need to add some additional functionality to it in order to be able to navigate around your scene.

Directional Light The default light source contained in all new Unity projects. Directional lights emit even and consistent lighting across the entire scene.

Update the main camera

Select the Main Camera in the Hierarchy. Update the X, Y, and Z coordinates to correspond to the sample we are recreating. This will update your starting position when you run the scene.

In the Hierarchy, select the Main Camera, and in the Inspector, scroll down to the bottom and select Add Component.

Select Scripts > First Person Control.

The First Person Control enables users to move around with the WASD keys as well as look around using the mouse.

Update the directional light

Select the Directional Light in the Hierarchy.

In the inspector window on the left side of the Unity Editor, under Transform, update the rotational coordinates to match that of the Ambisonics sample. This will adjust the light source’s direction and how it dissipates throughout the scene. It has a very negligible effect in such a simple scene, but when you view the completed scene later you’ll notice how the shading on the sphere is effected by these adjustments.

Recreate the plane

Now add a plane to the scene, this will act as the floor. Giving you a surface to navigate upon. Right click in the Hierarchy.

Select 3D Object > Plane.

First, adjust the default position and scale of the plane. Select the Plane in the Hierarchy. Under Position, update the Y coordinate to correspond to the sample we are recreating. This will ensure the plane is underfoot when running the sample. Additionally, Increase the Scale for the X, Y, and Z coordinates to match the sample. This will give you more space to move within your scene.

Next, update the material of the plane to match that shown in the example scene. In the Project window at the bottom of the Unity editor, navigate to Assets > Samples > Meta XR Audio SDK > version > Examples Scenes > materials.

Drag the Ground material file to the plane you created in the Scene window.

Recreate the audio source

Right click in the Hierarchy.

Select Audio > Audio Source.

Rename the new audio source to AmbisonicAmbience.

First, adjust the default position of the audio source. Select AmbisonicAmbience in the Hierarchy. Under Position, update the X, Y, and Z coordinates to correspond to the sample we are recreating. This will ensure the audio source is centered when running the sample. Note that this won’t effect how you perceive the sound within the example, as it is all-encompassing. Which is the usual nature of ambient sounds in a scene.

Next, update the Audio Resource to Afternoon Suburban Park Babbling Brook Birds Tetrametric in order to match the sounds we hear in the sample.

Now update the Output to Master (SpatializerMixer) to ensure the sounds are coming through on the proper channel for you to hear.

Enable the Loop option. Additionally, adjust the Volume and Spatial Blend to match the sample as well.

Next, update the 3D Sounds Settings to match the sample by setting the Doppler Level to 0 and the Spread to 360. This will ensure the sound doesn’t change based on the listeners velocity and that the sound traverses in all directions from the source.

Select Custom Rolloff in the Volume Rolloff dropdown and reduce the Max Distance down to 100.

Right click on the volume key in the bottom right corner of the 3D Sound Settings graph and select Edit Key… set 0 for Distance and set 1 for Volume. This will ensure that the volume is unaffected by distance from the source.

Now add some additional components to the new audio source. Select Add Component and search for Mesh Filter. Add this component and set the Mesh to Sphere, allowing you to identify the location of the audio source when you run the scene.

Next, select Add Component and search for Mesh Renderer. Add this component. Under the Materials dropdown, set the material to AmbisonicObject1 to match the sample.

Finally, select Add Component for a final time and search for Mesh Collider. The default settings already match the sample.

View completed scene

Use Link to view your new scene from your headset. Alternatively, Meta XR Simulator can be used to view the scene.

Open your newly created scene, Testing.

In your Unity project, press Play(►) to run the app on your headset.

Congratulations! You’ve recreated the Ambisonics sample scene.

Further modify and manipulate

You can take your newly created scene even further to get some additional experience implementing some of the other features provided in the Meta XR Audio SDK. Below is some guidance on how you might further develop your new scene.

To start, add an additional audio source, as depicted in the SourceDirectivity sample. This will allow you to gain an understanding of how audio source directivity can be utilized to create dynamic, layered sound scapes. Gain some experience with layered soundscapes and experience how multiple audio sources can be incorporated into a single scene.

Next, explore the acoustics features provided in Meta XR Audio SDK. These features provide spatial cues beyond the direct path HRTF, including reflections and reverb. This creates a sense of space and helps to anchor spatial audio sources into the world. You can select which acoustic model Meta XR Audio will use for rendering and then adjust the available parameters for acoustics. Try to implement the script featured in the RoomAcoustics sample scene into your scene and explore how you can modify it to change how the sounds in your scene are perceived.