Chapter 4: Adding Special Effects and Environmental Reverb to 3-D Sounds

Special effects add a lot of character to a sound. A sound can be distorted , compressed, echoed and parametrically equalized, and basically used and abused until you achieve the desired effect. After playing with all the special effects that can be applied to a sound, you might think it possible to write a complex game audio engine using only a very few recorded sounds. As audio engineers refer to a pure sound as dry , and one with special effects applied as wet , look at this chapter as where we begin to get wet in our programming adventure.

This chapter describes the preset audio effects available within DirectSound, and then demonstrates them using the Rumpus tool. Go to the AVBook\bin directory, and run the Rumpus tool again. Click the Add or Edit Sound button, and then look at the Special Effects group box (see Figure 4.1).

Figure 4.1: Special Effects group box.

Special Effects

In DirectSound, there are nine preset types of special effects that can be applied to a sound. The first eight effects are Chorus, Compressor, Distortion, Echo, Flanger, Gargle, ParamEq, and Reverb. These effects add some interesting character to the dry sounds that we so often hear. Because of differences in the way that it is implemented in DirectSound, and because we provide a more efficient alternative in Chapter 7, we are going to treat the last effect, Environmental Reverb, differently from the other eight effects.

However, the Rumpus tool demonstrates the use of all nine effects, easily enabling them to be added, combined and removed from any of the ten sound slots.

In this chapter, we ll concentrate on the coding needed to implement the special effects. The next chapter describes the audio background required to make meaningful changes to the parameters that are set for these effects. But first, start with a quick tour of the features of the Rumpus UI that we purposefully left out of the previous chapter.