Unified Ambience

The Unified Ambience system is used to handle ambient/background sounds in an environment via a single, Data Table-based system. The image below shows the system in use in the Audio Test Gym, which can be accessed by opening M2AudioTestGym_P, and activating the Ambience System sublevel.

Key Features

  • Definition of Ambient Sound Zones with a spline, allowing for irregular area shapes, and varied elevation.

  • Creation of presets for Ambience Zones, which can be easily created, and added to a defined area.

  • Efficient activation and deactivatuion of emitters to reduce the impact on performance.

How to Use the Unified Ambience System

The Unified Ambience System relies heavily on the use of splines. It is therefore advised to be familiar with Unreal's spline editing tools.

  1. Add an instance of BPM_M2_Audio_AmbienceController to your map. Only one instance is required - if one already exists, skip this step.

  2. Place an instance of BP_M2_Audio_AmbientZone near the area you want to populate with sounds.

  3. Select the AmbientZone actor, then select any spline point to edit the spline. You can then move/add/remove spline points as required.

  4. Add AmbientZones for all relevant areas, then assign an appropriate Ambience from the UnifiedAmbience Data Table, DT_M2_Audio_AmbientSoundscape.

  5. To author new ambient audio for this system, make a new data table with the S_M2_Audio_AmbientSoundscape Structure. Each Soundscape consists of the following four elements:

  • External Loop: A continuous sound playing from the perimeter of the AmbientZone, at the location closest to the listener.

  • External OneShots: Randomly-generated sounds that appear on the perimeter of the AmbientZone when the listener is outside.

  • Internal Loop: A continuous sound playing in 2D while the listener is inside the AmbientZone.

  • Internal OneShots: Randomly-generated sounds that appear around the listener while they are inside the AmbientZone. Additionally, the OneShots can be customised with the following parameters:

  • Sound: The audio asset to be triggered.

  • Volume: A volume multiplier.

  • Pitch: A pitch multiplier.

  • RepeatDelayMin: The minimum amount of time between instances of this sound being spawned.

  • RepeatDelayMax: The maximum amount of time between instances of this sound being spawned.

  • VolumeRandomisation: The amount of randomisation applied to the sound volume. This is added to or subtracted from the above multiplier.

  • PitchRandomisation: The amount of randomisation applied to the sound pitch. This is added to or subtracted from the above multiplier.

Parameters on the AmbientZone Actor

The Ambient Zone actor has a number of parameters that can be adjusted, as follows:

  • Ambience: The name of the ambience preset from the ambience data table.

  • Activation Distance: The distance at which the AmbienceZone is enabled.

  • Height Threshold: The vertical distance from the splie that is used to form the "volume". Any point within the spline, and within this distance (both above or below the spline) is considered to be "inside".

  • VolumeModifier: A multiplier for the AmbienceZone's volume.

  • Maximum External Sound Separation: The maximum distance from the closest point to the listener at which a randomised OneShot is spawned.

  • Inside Sound Spawn Box Size: The size of the box in which a randomised sound can be spawned while the listener is inside.

  • Zones To Disable Upon Entry: References to other AmbienceZones which should be muted when the listener enters the selected AmbienceZone.

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