Lesson 4

Table of Contents

Adding Cone Attenuation

Accounting for how sound changes over distance is important, but what about how sound changes when the source of that sound doesn’t move any further away, but instead turns away. For example, imagine that you’re listening to the sound of a trumpet, where the trumpet player is directly facing you at a distance of 3 meters. If that trumpet player now spins 180º, so that their back is facing you, would it sound the same? Because the bulk of the trumpet’s energy is projected forward, and the listener is behind, the sound would be perceived as quieter and more muffled. To account for these changes in a sound source's direction, Wwise offers something called cone attenuation.

You'll use cone attenuation to support the visual of the rotating teleporter panel. As the teleporter panel rotates you'll see that one side of the teleporter is blue and mirror-like. Imagine that this is the front of the teleporter, from which the sound you've implemented so far is being emitted. By adjusting the Cone Attenuation properties, you'll be able to hear when the front of the teleporter panel is facing the player, as opposed to when the plain back faces the player. Cone Attenuation properties are found in the lower- right area of the Attenuation Editor. There’s also an Attenuation Preview image that is designed to show you the relationship between the emitter and the listener.

  1. Select the Cone Attenuation check box.

    The Cone Attenuation properties are now available, as well as the Attenuation Preview area.

    The Attenuation Preview is designed to give you a visual representation, as well as a way to simulate the relationship between an emitter and a listener. It’s natural to think that the graphic for the cone attenuation puts the listener in the center of the circle, with the white dot representing the emitter; however, it’s just the opposite. As a whole, the diagram represents how the sound-emitting object in the game will project its sound into the world with that sound source positioned at the center of the circle. The position of the listener is defined by the white dot.

    The pie-shaped area at the top of the Attenuation Preview shows that if a listener is within that forward facing zone, no additional changes to sound emitter properties will be made. The pie-shaped area at the bottom of the Attenuation Preview shows that when the listener is behind the emitter, the emitter's object properties will be modified by the values displayed just to the left of the Attenuation Preview area. The areas on either side of the Attenuation Preview represent a transition area that will gradually change property values from those used in the top and bottom areas.

    It’s easiest to make some changes to see how the visual representation of the Attenuation Preview can be interpreted, and how you can use the Attenuation Preview to simulate changes in angle and distance of the sound emitter relative to the listener position.

  2. Change the Low-pass filter value to 50 and press Enter.

    Although you’ve made a change to the Low-pass filter, you won’t hear any change because this value will only be heard when the listener is looking at the back of the emitter. To do this, you need to move the listener behind the emitter.

  3. In the Attenuation Preview, drag the orange line around to the opposite side.

    Now you hear the obvious effect of the Low-pass filter. You may have also noticed that as you swung the dot behind the emitter, there was a gradual increase in the filter as you passed through the transition area.

  4. Drag the black line to -105 degrees.

    Now the listener is in the transitional zone. The size of the transition zone can be customized by modifying the Inner or Outer angle properties.

  5. Change the Outer angle value to 90 degrees and press Enter.

  6. Set the Low-pass filter value to 20, or to your liking.

    Now that we’re finished with the Teleporter SFX object, it will need an Event.

  7. Close the Attenuation Editor, then right-click the Teleporter SFX object and choose New Event > Play.

    The Name field of the Event is already conveniently highlighted, allowing you to simply start typing.

  8. Name the Event Teleporter and press Enter.


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