An AudioComponent is used to create and control an instance of sound inside your game.
Audio Component
The AudioComponent allows you to add a Sound Wave or Sound Cue as a sub-object to an Actor, providing a sound source.
For example, say you wanted a particle effect that resembles a fire in your level. While the particle effect alone can be used to convey the visuals of a fire, by adding an AudioComponent as a sub-Actor to it that plays an audio asset of a crackling fire, the fire effect will be that much more convincing.
You can change several of the properties or settings of the AudioComponent through Blueprints or C++ during runtime such as fading the audio in or out, playing or stopping it entirely, adjusting the volume and other settings which can be found on the Sound Actors page under the different properties sections.