Table of Contents

Wwise SoundSeed Air - Wind

SoundSeed Air consists of two separate plug-ins: SoundSeed Wind and SoundSeed Woosh. The SoundSeed Wind plug-in is a Wwise source plug-in that generates wind sounds as they pass through and around objects. These sounds are generated by using time-varying parameter sets to drive a synthesis algorithm. No source audio files are necessary as the wind sounds are completely synthesized. SoundSeed Wind allows you to save memory in your game because you no longer need the long looping wind ambience .wav files that you would have traditionally used.

[Note] Note

If you plan to develop, integrate, and distribute SoundSeed Air with your game, you need to purchase a separate license. For more information, contact the Audiokinetic sales team at: sales@audiokinetic.com.

For each source, a SoundSeed Wind scene is created. Each scene consists of the wind itself and one or more deflector objects. The actual wind movement is created by defining values for a variety of different properties, such as direction, speed, and gustiness. Deflector objects are created and then placed throughout the scene to define the characteristics of the wind sound as it passes around these objects. Each deflector object has its own set of properties, including frequency and gain. This gives you a great amount of power and flexibility to create almost any type of wind ambient sound in your game.

[Note] Note

Although SoundSeed Wind is a flexible synthesizer, it yields optimal results when using slowly evolving parameters. Glitches and other unwanted sounds may occur when we trying to create wind sounds that are best suited for SoundSeed Woosh.

Wind Propagation Through a Scene

SoundSeed Wind emulates the flow of wind through a scene; the direction specifies the point of entry of wind flow on to a scene. Thus you should expect pressure waves to hit the deflectors closest to the entry point first. The flow will then propagate through the scene as it is pushed by incoming wind. As it propagates, you will hear deflector objects that are placed farther from the entry point as they encounter the oncoming pressure wave. Note that higher wind speeds at the entry point push the flow at a quicker rate than slower speeds.

The following illustration demonstrates a typical scene where wind and a series of deflectors are defined using a set of properties. Deflectors will appear smaller or larger in size and lighter or darker in color depending on the frequency and gain property values assigned to them.

Using Automation Curves

A variety of other tools exist to help you further refine the wind sound. For example, both wind and deflector properties can be controlled over time using automation curves. You can create sophisticated curves by adding any number of points and using a variety of curve shapes. The following illustration shows an example of a sophisticated wind speed automation curve.

Cyclic Nature of Automation

When wind sounds are looped, the automation curves are repeated in a cyclical manner. When using very short durations, you may experience the phenomenon where, at increasing playback rates, the sound appears to speed up and slow down in a random way. This occurs because the space between each sample becomes larger than the actual automation curve. When this occurs, the next control sample will be taken from a different point at the beginning of the next cycle of the automation curve.

Distance-Based Attenuation

You can also apply distance-based attenuation to the wind sound. Basically, a -6 dB attenuation is applied each time the deflectors' distance is doubled after the Minimum distance. You can fine-tune the attenuation of the deflectors in your scene by specifying values for the following properties:

  • Minimum distance - The distance from the center of the scene, in all directions, where no attenuation gain is applied.

  • Roll-off factor - The slope of the attenuation curve, where higher values produce steeper slopes or faster attenuation. For example, a roll-off of 2 attenuations the wind sound twice as fast.

The following illustration demonstrates the attenuation model used by the SoundSeed Air plug-ins. Three different roll-off factors are used with the same min and max distances to show how the attenuation gain is applied in each case.

Controlling Properties using RTPCs

In Wwise, most properties can be modified in real time using the property sliders. Many of the properties can also be mapped to parameters in your game using RTPCs. A special indicator is placed beside the property value showing whether it uses an RTPC or not.

The following table describes the two types of RTPC indicators:

Indicator

Name

Description

RTPC - On

A property value that is tied to an in-game parameter value using RTPCs.

RTPC - Off

A property value is not tied to an in-game parameter value.