Has anyone figured out Control Buses (Audio Modulation Plugin)?

[Doug_Richardson]

@AudioFactory

Every single thing you could imagine, except for one node to apply those modulators to a Sound Cue or a SubMix, nor a place to apply them to something else in the editor, and the documentation is almost non existant and mentions nothing about that.

Audio Components, Sound Waves, and Sound Classes have a Modulation section. If you change the drop down to Override and check Modulate (see screenshot), then you can set the Volume Modulator to be either a Control Bus or a Parameter Patch. A Parameter Patch is an array of Control Busses that have a function applied to them and are then multiplied together to create the final value, like out = f1(bus1) * f2(bus2) * f3(bus3), where each fN is a function you can pick from a list.

NOTE: Although Sound Cues also have an Audio Modulation section, it does not work, nor is it meant to. See this How to get Audio Modulation to work with Sound Cues? for more info.

To adjust these values at runtime you have to create a Control Bus Mix that has a stage for each Control Bus you want to tweak. You then activate the Control Bus Mix to effect the busses. You can see what mixes are active by running the Console command: au.Debug.SoundModulation 1

For more info, check out Audio Modulation Mixing in UE4.26 Preview 1 by Dan Reynolds.

You can also checkout this AudioUE5 example project on github. Open the Audio Modulation map to see how you can use Control Buses, Control Bus Mixes, and Parameter Patches to mix sounds and also to adjust based on user settings.