4.2 Motoric Function

A further qualitatively specific connection between sound and image, which can be called the motoric function,^[6] refers to the joint occurrence of objects and movement noises. It is used in many racing games and flight simulators, when the vehicle steered by the player is permanently seen in the image, while the background is animated. At the sound level, motor noises can be heard which are coupled with the interaction and dynamically modulated in frequency and volume. Motoric functions are generated by adaptive audio, which dynamically reacts to the game action. The sound designer Andrew Clark explains the scenario: [T]he archetypal example of adaptive audio is the sound of a car engine in a racing game—when the user steps on the gas, the effect must change to reflect the engine’s changing RPM (revolutions per minute). This type of sound adds a unique extra dimension to the challenge of game sound design. Whereas an engine sound for a linear AV medium only has to fit with two contexts (the visual and the mix), an adaptive engine sound must also respond dynamically to pseudo-random user input events.^[7] In this case the dynamically adapted sound lends the visually rather static vehicle an appearance of motion, and the sound is perceived in the sense of Chion’s ergo audition as being controlled by the players. The car race simulations from the Gran Turismo series (Sony 1997–2008) provide an exemplary illustration of the motoric function between sound and image as explained above.