The IEZA framework for audio in games

Based on our review of literature and repertoire we have formulated a framework that uses an alternate approach to classify game audio: the IEZA framework. The primary purpose is to refine insight in game audio by providing a coherent organization of categories and by exposing the various properties of and relations between these categories.

The categories and dimensions of the IEZA framework will be described in the following paragraphs and are represented in the following illustration:

Caption: The IEZA framework

The first dimension

On one hand, the game environment provides sound that represents separate sound sources from within the fictional game world, for example the footsteps of a game character in a first-person shooter, the sounds of colliding billiard balls in a snooker game, the rain and thunder of a thunderstorm in a survival horror game and the chatter and clatter of a busy restaurant setting in an adventure game.

On the other hand, there is sound that seemingly emanates from sound sources outside of the fictional game world, such as a background music track, the clicks and bleeps when pressing buttons in the Heads Up Display (HUD), as well as sound related to HUD-elements such as progress bars, health bars and events such as score updates. In other words, sound originating from a part of the game environment that is on a different ontological level as the fictional game world.

Stockburger (2003) was the first to describe this distinction in the game environment and uses the terms diegetic and non-diegetic. These two terms originate from literary theory, but are used in film sound theory as well (for instance by Chion (1994, p.73)). When they are applied to game environments, one has to consider the fact that games often contain non-diegetic elements like buttons, menus and health bars that are visible on screen⁴. Film rarely features non-diegetic visuals and even if it does, these visuals are not often accompanied by sound.

The diegetic side of the framework

Effect

The diegetic side of the IEZA framework consists of two categories. In the first category, named Effect, audio is found that is cognitively linked to specific sound sources belonging to the diegetic part of the game. This part of game audio is perceived as being produced by or is attributed to sources, either on-screen or off-screen, that exist within the game world. Common examples of the Effect category in current games are the sounds of the avatar (i.e. footsteps, breathing), characters (dialog), weapons (gunshots, swords), vehicles (engines, car horns, skidding tires) and colliding objects.

Of course, there are many games that do not feature such realistic, real-world elements and therefore no realistic sound sources. Examples are games such as Tetris, Rez and New Super Mario Bros. The latter features only a few samples of speech (that of the characters Mario and Luigi) while the rest of the audio consists of synthesized bleeps, beeps and plings. These non-iconic signs refer to activity of the avatar Mario and events and sound sources within the diegetic part of the game and we therefore consider these part of the Effect category. Sound of the Effect category generally provides immediate response of player activity in the diegetic part of the game environment, as well as immediate notification of events and occurs, triggered by the game, in the diegetic part of the game environment.

Sound of the Effect category often mimics the realistic behavior of sound in the real world. In many games it is the part of game audio that is dynamically processed using techniques such as real-time volume changes, panning, filtering and acoustics.

⁴ When the terms diegetic and non-diegetic are used in the context of games, one has to acknowledge the fact that non-diegetic information can influence the diegesis, because of interactivity. For example, a player controlling an avatar can decide to take caution when noticing a change in the non-diegetic musical score of the game, resulting in a change of behavior of the avatar in the diegetic part of the game. In some cases, this trans-diegetic process needs to be taken into account when using the terms diegetic and non-diegetic. Yet, diegetic and non-diegetic have more or less become the established terms within the field of game studies to describe this particular distinction in the game environment.

Zone

The second category, Zone, consists of sound sources that originate from the diegetic part of the game and which are linked to the environment in which the game is played. In many games of today, like Grand Theft Auto: San Andreas and FIFA 07, such environments are a virtual representation of environments found in the real world. A zone can be understood as a different spatial setting that contains a finite number of visual and sound objects in the game environment (Stockburger, 2003, p. 6). It might be a whole level in a given game, or part of a set of zones constituting the level.

Sound designers in the field often refer to Zone as ambient, environmental or background sound. Auditory examples include weather sounds of wind and rain, city noise, industrial noise or jungle sounds. The main difference between the Effect and Zone category is that the Zone category consists chiefly of one cognitive layer of sound instead of separate specific sound sources. Also, in many of today's games, the Effect category is directly synced to player activity and game events in the diegetic part of the game environment.

Sound design of the Zone category is generally linked to how environments sound in our real world. Zone also often offers "set noise", minimal feedback of the game world, to prevent complete silence in the game when no other sound is heard. The attention (and therefore immersion in the game) of the player can benefit from this functionality.