3D Spatial Audio

3D Spatial Audio brings the real-world sound experience to the virtual world, providing an immersive audio experience for users. Agora's spatial audio technology enables you to simulate the propagation characteristics of sound in a physical environment within a virtual interactive scene.

• Ultra-realistic space shaping effect

  Utilize technologies such as range audio, sound blur, and air attenuation simulation to perfectly simulate the real auditory experience.

  • Set the spatial positions of users in real time to give a sense of change in the distance, direction, and orientation of other users.
  • Update the spatial position of the media player, to add a sense of space to background sounds, accompaniments, and other media resources.
  • Add 3D Spatial Audio effects such as sound blurring and air attenuation by adjusting audio settings to perfectly simulate the real audio experience.

• 3D High Fidelity

  • Sound effects are processed and rendered based on the facial orientation, sound source orientation, and relative position of the sound source in 3D space.
  • Supports 48 kHz full-band sampling and 3D high-fidelity audio processing and rendering.

• Multi-platform support

  Supports iOS, Android, macOS, Windows, Web, Unity, Flutter, React Native, Electron, Unreal and other platforms.

• Ultra-low latency, low power consumption, and low cost

  The spatial audio algorithm adopts an advanced front-end processing mode and synchronizes spatial coordinates through cloud services. The end-cloud collaborative processing mode effectively reduces overall latency and power consumption.

Compared to traditional stereo, which relies on left and right channels, spatial audio technology greatly enhances the depth and realism of sound. The following table highlights these enhancements:

Feature	Traditional Stereo	Agora Spatial Audio
Dimensionality	Left and right dimensions	Represents sound in a full 3D space using the x, y, and z axes of the world coordinate system, corresponding to right, top, and front dimensions
Spatial Perception	Adjust the volume of the left and right channels to create a spatial sound	Utilizes advanced spatial audio algorithms to create a realistic soundscape by manipulating parameters like distance, direction, and orientation
User Experience	Flat	Immersive, three-dimensional, and natural, delivering a realistic auditory experience

In the Voice Chat Room app, user avatars are arranged in a grid, each assigned specific coordinates and a direction. During interaction, the volume and direction of each user's voice correspond to their location. As you drag your avatar across the screen, the volume of another user decreases as you move away and disappears when you exceed a certain distance, simulating real-world sound propagation.

In 3D environments like games and the Metaverse, spatial audio technology can enhance experiences in the following ways:

Audio Blurring	Enable audio blurring for specific users or media. For example, in a coffee shop, use this to create a "whispering" effect where other users hear muffled conversations.
Range Audio	Set audio reception range based on the scene. The farther the sound travels, the fainter it becomes. Adjust the attenuation factor for different effects: Jungle scene: Set to 0.9 for fast sound decay. Plain scene: Set to 0.1 for slower sound decay over a longer distance.
Ultra-Realistic Space	Assign virtual characters 3D coordinates for a realistic spatial experience, including: Avatar coordinates (x, y, z). The coordinates of the avatar in 3D space. Virtual character face orientation coordinates (x, y, z): The face orientation coordinates of the virtual character in the scene. Virtual character head top orientation coordinates (x, y, z): Coordinates of the virtual character's head top orientation, which can be combined with the face orientation coordinates to determine the virtual character's actions and postures. For example, when the virtual character lies flat, the face is facing the sky and the top of the head is facing forward. Coordinate system (left or right-handed). Whether the rectangular coordinate system uses a left-handed coordinate system or a right-handed coordinate system. Only one coordinate system can be used in a scene.
Sound Insulation Area	Create sound-insulated zones with customized sound attenuation. When a receiver outside the area listens to the sound source in the area, they experience the attenuation effect of the sound in the real environment on encountering the building partition. For example, in a KTV scene, sounds from inside a box can be faintly heard from outside. Opening the door instantly amplifies the sound.

In virtual meetings, spatial audio can arrange users around the host, with each microphone having directional sound. This setup mimics a real-world conference room, providing a more immersive and less tiring experience compared to traditional online meetings.

This page shows you how to implement 3D Spatial Audio in your app.

Agora provides a local Cartesian coordinate system calculation scheme for setting up 3D Spatial Audio positions for users and the media player.

Use an instance of ILocalSpatialAudioEngine to implement 3D Spatial Audio. Call updateSelfPosition and updateRemotePosition to specify the spatial coordinates of local and remote users in the channel. Voice SDK calculates the relative positions of local and remote users. This enables local users to experience the 3D Spatial Audio of remote users.

Call updateSelfPosition and updatePlayerPositionInfo methods of the ILocalSpatialAudioEngine class to update the spatial coordinates of local users and the media player. The SDK calculates the relative positions of local users and the media player. This enables local users to experience the 3D Spatial Audio effect of the media player.

Ensure that you have implemented the SDK quickstart in your project.

The following figure shows the workflow you implement to provide 3D Spatial Audio for users and the media player:

Call the create method of the ILocalSpatialAudioEngine class to create an instance of the spatial audio engine. Then, call initialize to enable spatial audio.

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localSpatial = ILocalSpatialAudioEngine.create();

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LocalSpatialAudioConfig localSpatialAudioConfig = new LocalSpatialAudioConfig();

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localSpatialAudioConfig.mRtcEngine = engine;

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localSpatial.initialize(localSpatialAudioConfig);

To set the desired audio encoding properties, call setAudioProfile.

Call setAudioScenario to set the scenario to AUDIO_SCENARIO_GAME_STREAMING for the best sound quality effect.

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engine.setAudioProfile(io.agora.rtc2.Constants.AUDIO_PROFILE_MUSIC_STANDARD);

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engine.setAudioScenario(io.agora.rtc2.Constants.AUDIO_SCENARIO_GAME_STREAMING);

To set the maximum number of audio streams that can be received within the audio receiving range, call setMaxAudioRecvCount. The recommended maxCount value is ≤ 16.

To set the maximum range of receivable audio, in meters, call setAudioRecvRange. The recommended value range is ＞ 0.

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localSpatial.setMaxAudioRecvCount(2);

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localSpatial.setAudioRecvRange(AXIS_MAX_DISTANCE);

In the user space audio scenario, call the updateSelfPosition and updateRemotePosition methods to update the positions of the local user and remote users respectively.

In the media player spatial audio scenario, call the updateSelfPosition and updatePlayerPositionInfo methods to update the position of the local user and the media player, respectively.

Typically, you call these methods when:

• A new user joins the channel.
• The relative positions of the local user, a remote user, or the media player changes.
• There are other changes in your specific scenario.

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// Update local user position

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float[] pos = getVoicePosition(localIv);

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float[] forward = new float[]{1.0F, 0.0F, 0.0F};

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float[] right = new float[]{0.0F, 1.0F, 0.0F};

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float[] up = new float[]{0.0F, 0.0F, 1.0F};

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localSpatial.updateSelfPosition(pos, forward, right, up);

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// Update the remote user's position

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if (remoteLeftTv.getTag() == null) {

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remoteLeftTv.setTag(uid);

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remoteLeftTv.setVisibility(View.VISIBLE);

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remoteLeftTv.setText(uid + "");

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RemoteVoicePositionInfo info = getVoicePositionInfo(remoteLeftTv);

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Log.d(TAG, "left remote user >> pos=" + Arrays.toString(info.position));

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localSpatial.updateRemotePosition(uid, info);

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remoteLeftTv.setOnClickListener(v -> showRemoteUserSettingDialog(uid));

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} else if (remoteRightTv.getTag() == null) {

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remoteRightTv.setTag(uid);

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remoteRightTv.setVisibility(View.VISIBLE);

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remoteRightTv.setText(uid + "");

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localSpatial.updateRemotePosition(uid, getVoicePositionInfo(remoteRightTv));

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remoteRightTv.setOnClickListener(v -> showRemoteUserSettingDialog(uid));

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}

To set spatial audio parameters for the remote user or media player, call setRemoteUserSpatialAudioParams or setSpatialAudioParams. To implement specific sound effects, refer to the following parameter settings:

• Air attenuation effect

  Set enable_air_absorb to true and set speaker_attenuation to the desired sound attenuation coefficient.

• Sound blur effect

  Set enable_blur to true

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// Enable air absorption effect

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spatialAudioParams.enable_air_absorb = true;

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// Enable sound blur effect

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spatialAudioParams.enable_blur = true;

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// Set spatial audio parameters for the media player

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engine.setRemoteUserSpatialAudioParams(uid, spatialAudioParams);

To define a sound isolation zone and set a sound attenuation coefficient call setZones. This feature simulates the real-world effect of sound attenuation when the sound source is inside a sound isolation zone while the receiver is outside or vice versa. It mimics how sound behaves when encountering obstacles like building partitions.

Optionally, call setRemoteAudioAttenuation or setPlayerAttenuation to set the sound attenuation properties for the user and media player, respectively, and specify whether to use this setting to forcefully override the sound attenuation factor in setZones.

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SpatialAudioZone mediaPlayerLeftZone = new SpatialAudioZone();

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mediaPlayerLeftZone.zoneSetId = 1;

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mediaPlayerLeftZone.audioAttenuation = 1f;

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float[] voicePosition = getVoicePosition(zoneTv);

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float[] viewRelativeSizeInAxis = getViewRelativeSizeInAxis(zoneTv);

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mediaPlayerLeftZone.position = new float[]{voicePosition[0], voicePosition[1], 0};

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mediaPlayerLeftZone.forward = new float[]{1.f, 0, 0};

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mediaPlayerLeftZone.right = new float[]{0, 1.f, 0};

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mediaPlayerLeftZone.up = new float[]{0, 0, 1.f};

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mediaPlayerLeftZone.forwardLength = viewRelativeSizeInAxis[1];

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mediaPlayerLeftZone.rightLength = viewRelativeSizeInAxis[0];

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mediaPlayerLeftZone.upLength = AXIS_MAX_DISTANCE;

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localSpatial.setZones(new SpatialAudioZone[]{mediaPlayerLeftZone});

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localSpatial.setRemoteAudioAttenuation(uid, 0.5f, false);

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localSpatial.setPlayerAttenuation(mediaPlayer.getMediaPlayerId(), 0.5f, false);

To optimize the audio experience, call setHeadphoneEQPreset to choose a preset headphone equalizer.

If the preset values do not provide the desired effect, call setHeadphoneEQParameters to self-adjust headphone equalization. After you execute this method, the preset values set by setHeadphoneEQPreset are overwritten.

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engine.setHeadphoneEQPreset(io.agora.rtc2.Constants.HEADPHONE_EQUALIZER_OVEREAR);

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engine.setHeadphoneEQParameters(10, 10);

During a session, pause or turn off spatial audio as follows.

To disable a remote user's spatial audio, or to remove a remote user who has exited the channel, call removeRemotePosition to delete the user's spatial position information and save computing resources.

caution

When a remote user leaves the channel, call removeRemotePosition to delete the user's spatial position information. Otherwise, the local user may not be able to hear the spatial audio from other remote users.

To restore the user's spatial audio, call updateRemotePosition to reset the remote user's position information.

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// Pause spatial audio for a specific remote user locally

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localSpatial.removeRemotePosition(uid);

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// Resume spatial audio for a specific remote user locally

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localSpatial.updateRemotePosition(uid, getVoicePositionInfo(remoteLeftTv));

If you do not want to continue to experience local spatial audio, call clearRemotePositions to delete the spatial position information of all remote users.

caution

Calling this method prevents the local user from hearing the audio of all remote users. Agora recommends using this method with caution.

To resume hearing the remote user's audio later, call muteAllRemoteAudioStreams(false) to subscribe to the remote audio streams again.

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// Remove all remote users' spatial positions

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localSpatial.clearRemotePositions();

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// Resume subscribing to remote users' audio streams

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localSpatial.muteAllRemoteAudioStreams(false);

To unpublish the local audio stream, call muteLocalAudioStream(true).

To enable spatial audio again, call the same method with the parameter set to false.

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// Mute the local audio stream

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localSpatial.muteLocalAudioStream(true);

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// Unmute the local audio stream

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localSpatial.muteLocalAudioStream(false);

To turn off spatial audio, call the enableSpatialAudio method of the RtcEngine instance and set the parameter to false. This resets all settings related to spatial audio.

To enable spatial audio again, call this method again and set the parameter to true, and then call the relevant APIs again to set the spatial audio effect.

Call the destroy method of the ILocalSpatialAudioEngine class to free up resources.

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// Disable spatial audio

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engine.enableSpatialAudio(false);

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// Destroy the ILocalSpatialAudioEngine object

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ILocalSpatialAudioEngine.destroy();

This section contains content that completes the information on this page, or points you to documentation that explains other aspects to this product.

Agora provides the SpatialSound open-source sample project for your reference. Download the project or view the source code for a more detailed example.

• ILocalSpatialAudioEngine
  • initialize
  • muteAllRemoteAudioStreams
  • setMaxAudioRecvCount
  • setAudioRecvRange
  • setDistanceUnit
  • updateSelfPosition
  • updateRemotePosition
  • updatePlayerPositionInfo
  • clearRemotePositions
  • setRemoteAudioAttenuation
  • setZones
  • setPlayerAttenuation
  • destroy
• IMediaPlayer
  • setSpatialAudioParams
• RTCEngine
  • enableSpatialAudio
  • muteLocalAudioStream
  • setHeadphoneEQParameters
  • setHeadphoneEQPreset
  • setRemoteUserSpatialAudioParams