Table of Contents

Defining the Attenuation curves for Various Object Properties

To create the attenuation of objects in Wwise, you can create a series of curves that define a relationship between certain properties in Wwise, such as Volume and Low-Pass Filter, and the distance the point source is from the listener in game.

Each curve uses a max distance value that defines the point where maximum attenuation of the object occurs. Since sounds emanate from an omni-directional source, the max distance value creates a spherical radius around each source.

By default, the attenuation of your object will be applied using a linear interpolation from the source to the max distance.

Although this may work in most cases, specific objects may require more advanced curves. To have more control over the Attenuation curve, you can add control points. These points break up the Attenuation curve so that you can better manage the attenuation of your object.

To create a more detailed and complex positioning curve, you can also define the shape of each curve segment. A curve segment is any part of the curve between two control points. You can choose from a variety of curve shapes, including linear, constant, logarithmic, exponential, and s-curve. For more information on specifying curve shapes and other information about working in the graph view, refer to Chapter 43, Getting to Know the Graph View.

You can create Attenuation curves for the following Wwise properties:

  • Output Bus Volume - The attenuation or amplitude of the signal routed to the audio output bus.

  • Auxiliary Send volumes - The attenuation or amplitude of the signal sent to game-defined and user-defined Auxiliary Busses.

  • Low-pass filter - The recursive filter that attenuates high frequencies based on a specified value. The units for the low-pass filter represent the percentage of Low-Pass Filtering that has been applied, where 0 means no low-pass filtering (signal unaffected) and 100 means maximal attenuation.

  • High-pass filter - The recursive filter that attenuates low frequencies based on a specified value. The units for the high-pass filter represent the percentage of high-pass filtering that has been applied, where 0 means no high-pass filtering (signal unaffected) and 100 means maximal attenuation.

  • Spread - The amount or percentage of audio that is spread to neighboring speakers allowing for sounds to change over distance from a point source at low values to a completely diffused propagation at high values. A value of 0 means that the channels of an emitting source positioned next to a speaker will only be played in that speaker. A value of 100 means that the channels of the emitting source will be diffused so that they are heard or felt through all speakers.

  • Focus - The percentage value is used to condense the virtual emitters generated by the spread value. For a focus of 0%, the virtual emitters remain unchanged, but at higher values each virtual point is moved closer to the source channel origin.

Attenuation property values are relative, which means that the attenuation value is added to the existing property values of the associated object.

To define the Attenuation curves:

  1. Load an object into the Property Editor and switch to the Positioning tab.

  2. Within the Attenuation group box, click the selector to choose or create an Attenuation ShareSet.

    [Note] Note

    You must enable Listener Relative Routing to activate the Attenuation group box.

  3. Click Edit….

    The Attenuation Editor opens with the property settings of the selected attenuation instance.

  4. In the Max distance text box, specify the distance from the source point where the sound will reach its maximum attenuation.

    [Note] Note

    After the max distance value, the attenuation settings remain constant.

  5. In the Curves group box, select the Output Bus Volume curve from the list.

    The default Output Bus Volume curve is displayed in the graph view.

    [Note] Note

    The first point on the curve always represents the point source and the last point on the curve always represents the max distance value.

  6. Manipulate the Output Bus Volume Attenuation curve, by doing any of the following:

    • Add points along the curve.

    • Drag points to a new location or type specific values into the X and Y coordinate boxes.

    • Define the shape of each curve segment.

    [Note] Note

    For specific information on zooming or panning in the graph view, displaying several curves simultaneously, adding, moving, or deleting points, specifying the scaling method, or changing the shape of curve segments, refer to Chapter 43, Getting to Know the Graph View.

  7. For the remaining curves, select one of the following options from the Curve list:

    • None to not use an Attenuation curve for the corresponding property. When “None” is selected, the corresponding property is NOT attenuated and remains at its full strength.

    • Use Output Bus Volume to use the same Output Bus Volume curve for the corresponding property. This option is only available for the Auxiliary send volumes curve.

    • Custom to create a custom Attenuation curve for the corresponding property.