To simulate a natural roll-off as the source moves away from the microphone in game, you can use the attenuation properties. The attenuation in Wwise is based on the following two properties:
Distance attenuation: Influences the intensity of the signal based on the distance between the emitter and the listener.
Cone attenuation: Influences the intensity of the signal based on the orientation of the emitter in relation to the listener.
The distance attenuation is defined using a series of curves. These curves map Wwise property values, such as volume, to a distance value. By defining the properties of each point along the curve, you can control the volume attenuation for objects as they move away from the listener.
The cone attenuation is defined using a series of angles that define areas in front of, beside, and in back of the source. By defining these different areas around the source, you can simulate attenuation of an object based on the orientation of the object in game.
Like Effects, you can create instances of your Attenuation properties that can then be shared across many different objects within Wwise using ShareSets.