Exercise - Spatialize button interaction sounds

  • 3 minutes

In this module, you'll learn how to spatialize the button interaction sounds and also learn how to use an audio clip to test spatialized button interaction.

Add a button

  1. To add the Button prefab, in the Project window, select Packages and type "PressableButtonHoloLens2" in the search bar.

    Screenshot of Button prefab in Assets.

  2. The button prefab is the entry represented by a blue icon. Click and drag the PressableButtonHoloLens2 prefab into the Hierarchy. With the PressableButtonHoloLens2 object still selected, in the Inspector window, configure the Transform component as follows:

    • Position: X = 0, Y = -0.4, Z = 2
    • Rotation: X = 0, Y = 0, Z = 0
    • Scale: X = 1, Y = 1, Z = 1

    Screenshot of Button transform. To focus in on the objects in the scene, you can double-click on the PressableButtonHoloLens2 object, and then zoom slightly in again:

Spatialize button feedback

In this step, you'll spatialize the audio feedback for the button. For related design suggestions, see spatial sound design

In the Audio Mixer window you'll define destinations called Mixer Groups, for audio playback from Audio Source components.

  1. To open the Audio Mixer window, In the Unity menu, select Window > Audio > Audio Mixer:

    Screenshot of Open Audio Mixer Window.

  2. Create a Mixer by clicking the '+' next to Mixers and enter a suitable name to the Mixer for example, Spatial Audio Mixer. The new mixer will include a default Group called Master.

    Mixer panel with first mixer.

  3. In the Hierarchy window, select the PressableButtonHoloLens2 then in the Inspector window find the Audio Source component and Configure the Audio Source component as follows:

    1. For the Output property, click the selector and choose the Mixer that you created.
    2. Check the Spatialize checkbox.
    3. Move the Spatial Blend slider to 3D (1).

    Screenshot of Button audio source.

Note

If you move Spatial Blend to 1 (3D) without checking the Spatialize checkbox, Unity will use its panning spatializer, instead of the Microsoft Spatializer with HRTFs.

Adjust the volume curve

By default, Unity will attenuate spatialized sounds as they get farther from the listener. When this attenuation is applied to interaction feedback sounds, the interface can become more difficult to use.

To disable this attenuation, you need to adjust the Volume curve In the Audio Source component.

  • In the Hierarchy window, select the PressableButtonHoloLens2 then in the Inspector window navigate to Audio Source > 3D Sound Settings and Configure as follows:

    1. Set the Volume Rolloff property to Linear Rolloff
    2. Drag the endpoint on the Volume curve (the red curve) from '0' on the y axis up to '1'
    3. To adjust the shape of the Volume curve to be flat, drag the white curve shape control to be parallel to the X axis

    Screenshot of Button 3D sound settings.

Test the spatialize audio

To test the spatialize audio in the Unity editor you've to add an audio clip in the Audio Source component with Loop option checked in on PressableButtonHoloLens2 object.

In the play mode move the PressableButtonHoloLens2 object from left to right and compare with and without spatial audio enabled on your workstation. You can also change the Audio Source settings for testing by:

  1. Moving the Spatial Blend property between 0 - 1 (2D non-spatialized and 3D spatialized sound)
  2. Checking and unchecking the Spatialize property

Try out the app on HoloLens 2. In the app, you can click the button and hear the spatialized button interaction sounds.

Note

Building and testing on HoloLens 2 is not mandatory. Alternatively, you can test on the HoloLens 2 Emulator if you don't have a device. Devices can be purchased at HoloLens.com.