Nightmares and Soundscapes: Implementation of Acoustic Ecology Related Sound Design Techniques to Better Terrify your Players

Guest Contribution by Dr Tom Garner

This article addresses contemporary concepts regarding how we attune to sound within a fear context and discusses the potential impact of these ideas upon sound design, specifically with regards to evoking disorientation in survival horror computer games. Relevant theory is distilled to consider an ecological perspective of sound experience within a survival horror game context. We then discuss how this approach will likely impact upon future practice as we, as designers, strive to develop sound production and implementation techniques that have increasingly greater potential to unnerve, panic and otherwise terrify even the most hardcore of gamers.

Generating Fear From Sound

Whilst the affective potential (the ability to evoke an emotional response) of music is a well-established field of research, the equivalent examination into non-musical/non-speech sound (sound effects, ambient sound, etc.) has undergone relatively less investigation. Of the research that has been conducted, several objective acoustic characteristics (that are expected to be effective irrespective of other factors/contexts) include:

• Rapid onset/offset (tempo): Increases anxiety by way of connoting urgency.
• Source delocalisation: Obscuring the source’s location via masking with other sounds, moving a sound quickly and irregularly through a 3D sound environment and/or, utilising reverberation to generate reflections that disorientate the listener.
• Extreme frequency: creating high screeches or low rumbles that reliably connote threat of an unknown nature.
• Defamiliarisation through distortion: taking a sound that is characteristically comforting and distorting or blending it with other sounds to decontextualize the original sound and create a sense of the uncanny and unease.
• Immediate attack: Sudden shifting from silence/low volume to high volume.
• Extended acousmatic attack: Slowly increasing volume but with no visible source, suggesting an unseen threat is approaching.

Recent testing has confirmed however, that employing such techniques does not guarantee success and that to truly terrify your audience you must first understand the overall environment within which player, game and soundscape interact.

Virtual Acoustic Ecology & Game Sound Localisation

Recent research into computer game sound at the University of Aalborg in Denmark has brought together ideas relating to acoustic ecology in an attempt to develop a framework that illustrates how the human auditory system processes sound stimuli within a survival horror game context. The basic premise of an acoustic ecology is that there exist interactions between sound, the listener and the surrounding environment. For example, a player can be affected by the sounds of a game (e.g. ducking for cover when enemy fire is heard) but can also affect the sound themselves, and in real time (e.g. moving further from the source of a sound to reduce its audible volume). Various ecological phenomena (which could include emotions, physiology, memory, ability/implicit skill, environmental factors, etc.) have the potential to influence our sensation of fear in response to a sound. For example, if, before commencing a gameplay session, a player had a distinctly elevated heart-rate (e.g. from exercising) it is possible that their response to a frightening sound would be limited as their already heightened heart-rate would not rise in response to the stimulus (a physiological change that many associate with fear when they experience it. Environmental factors such as reducing ambient noise or turning off all of the lights before play are well established and commonly practiced by players who wish to enhance their horror experience.

Within the context of a first-person perspective game, acoustic ecology has particular relevance to sound design as the primary characteristic of a first-person simulation is a virtual recreation/approximation of a real world environment (as would be experienced by the player). As the player becomes immersed in the game they become projected into the virtual space of the avatar. The diegetic space of the game merges with their living room as the sound is not restricted to a two-dimensional plane and, depending on available technology, can surround them. Consequently, the soundscape reveals information relevant to them and their position, rather than their avatar. This, essentially, is what is known as a virtual acoustic ecology, a circumstance in which the audio propagation is artificial and the events/sources of the sound are virtual but there remains an ecological relationship between listener, sound and environment.

In relation to localisation, the role of sound within a virtual ecology is to give the player a sensation of presence within the virtual space; to influence and reinforce player-action. In this sense, localisation is not limited to identification of sound-object positioning but extends to time of day, period in history, architectural nature of the space and relative position to various events/objects. These functions of game sound reveal various ways in which we can position ourselves and other environmental objects across space, time and context. In addition, they present various opportunities to achieve the antithesis effect, delocalisation, with which we can disorient a player, undermine their confidence and comfort, ultimately to prime them for a high-intensity experience of fear.

Ecology-Based Delocalisation Techniques

The traditional approaches to sound delocalisation are documented above and characteristically involve application of digital signal processing techniques that obscure the location of a sound. The application of this technique within a contemporary FPS game is typically rather limited because many players employ a stereo audio output that is not optimally positioned for localisation and, as a result, find it difficult to position a sound within virtual space even if the designer has intentionally set out to achieve this. Therefore, to create a more successful sense of disorientation, designers should consider undermining other forms of localisation.

One such approach presents a clear sonification, allows the listener time to become accustomed to it, then distorts, masks or removes the sound to confuse and disorientate. Such a technique could relate to positioning and direction for increased effect. For example, in a game the player is required to listen for a wind-blowing sound to navigate through a maze of tunnels. They are given time to utilise this technique effectively for a period until they begin to become accustomed to the routine and begin to take the sound-guide for granted. At this point the sound is removed and the player is stripped of their best resource for escape.

Another effective approach involves distorting the sonic characterisation of the environment. For example as the player is traversing a woodland environment, the soundscape characterisation matches the location (birds singing, wind blowing through the trees, etc.). As the player becomes acclimatised to their environment, confident of their location, the soundscape shifts to undermine this certainty. A mechanical whirring is sounded overhead and the player’s footsteps begin to suggest a metallic surface rather than a woodland floor, causing them to question their location. They are not where they first believed they were.

Of course there are no absolute guidelines for implementation of these techniques and it is vital to consider the expectations and experience of the player. In many circumstances players expect deception and prepare themselves accordingly. The key lies in player-empathy and in visualising their perceptual journey through your game to predict their attitudes, feelings and actions. Within an ecological perspective, how one sound may influence the player’s perception of the next must be considered and the soundscape as a whole must be carefully scrutinised. Success at this technique will surely prime the player for a genuinely frightening experience when the monsters inevitably start squirming their way out of the woodwork.

Dr Tom Garner is a postdoctoral researcher at Aalborg University in Denmark. His research focuses on sonic emotioneering, real-time gamesound generation/processing, biometric control systems and affective developments in intelligent agents. Check his site for details of his past and future research and publications. Many thanks to Dr Garner for contributing to our ‘acoustics’ theme.