Typologies for game audio

Several typologies and classifications for game audio exist in the field. The most common classification is based on the three types of sound: speech, sound and music which seems derived from the workflow of game audio production, each of these three types having its own specific production process. Award-winning game music composer Troels Follman (2004) extends this classification by distinguishing vocalization, sound-FX, ambient-FX and music and even divides each category into multiple subcategories.

Although these three terms are widely used by many designers in the game industry, a classification based on the three types of sound does not specifically provide an insight in the organization of game audio and says very little about the functionality of audio in games.

A field of knowledge that is closely related to game audio is that of film sound. A commonly known film sound categorization comes from Walter Murch in Weis and Belton, (1985: 357). Sound is divided into foreground, mid-ground and background, each describing a different level of attention intended by the designer. Foreground is meant to be listened to, while mid-ground and background are more or less to be simply heard. Mid-ground provides a context to foreground and has a direct bearing on the subject in hand, while background sets the scene of it all. Others, such as film sound theoretician Michael Chion (1994), have introduced similar "three-stage" taxonomies.

We foresee that this classification can play an important role in the recently emerged area of real time adaptive mixing in games, which revolves around dynamically focusing the attention of the player on specific parts of the auditory game environment. However, these three levels of attention provide no insight in the structure and composition of game audio.

Friberg and Gardenfors (2004, p.4) suggest another approach, namely a categorization system according to the implementation of audio in three games developed within the TiM project³. In their approach, audio is divided according to the organization of sound assets within the game code. Their typology consists of avatar sounds, object sounds, (non-player) character sounds, ornamental sounds and instructions.

Besides the considerable overlap between the categories of this categorization (for instance, the distinction between object sounds and non-player character sounds can be rather ambiguous), this approach is very specific to only specific game designs. It says very little about the structure of sound in games.

Axel Stockburger (2003) combines both the approach of sound types and how sound is organized in the game code, but also looks at where in the game environment sound is originating from. Based on his observation of sound in the game Metal Gear Solid 2, Stockburger differentiates five categories of "sound objects": score, effect, interface, zone and speech.

Although Stockburger is not consistent when describing categories of sound on one hand (zone, effect, and interface) and types of sound on the other (score [or music] and speech), the approach of looking at where in the game environment sound is emitted can help distinguish an underlying structure of game audio. The three categories of sound (effect, zone, interface) are very close to a framework and therefore a good starting point. But in order to develop a coherent framework, a clear distinction between categories of sound and types of sound is needed.

We may conclude that the field of game theory does not yet provide a coherent framework for game audio. Current typologies say little about the structure of game. Designers and researchers have not yet arrived at a definition of sound in games that is complete, usable and more than only a typology. In the following paragraph we will present an alternative framework for game audio.

³ A project that researched the adaptation of mainstream games for blind children: http://inova.snv.jussieu.fr/tim/