Saturday, February 11, 2017

Procedural Sound Design

In games audio, "procedural sound design" or "procedural audio" are used to create a wider sound palette. It is necessary here to clarify exactly what is meant by "Procedural". "Procedural audio is non-linear, often synthetic sound, created in real time according to a set of programmatic rules and live input" (Farnell, 2007, pg.1) Computer music or sounds sometimes are used or viewed as datas (eg. Sonification). Sonification is "a technique that uses data as input, and generates sound signals" (Hermann, 2008, pg.1) Unlike Sonification, procedural sound design is an audio process generated by computer, similar to "generative sounds". However, generative sounds are not procedural sounds. Generative is an abstract term, algorithmic, procedural and AI (artificial intelligence) sound are all generative. However the definition of "generative" is commonly defined as a piece that "requires no input, or the input is given only as initial conditions prior to execution" (Farnell, 2007, pg.3). An example of a generative piece would be Brian Eno's Music for Airport (Eno, 1978). In other words, generative sounds are not interactive. Game audio focused on interactive sounds. "Procedural sound design is about sound design as a system, an algorithm, or a procedure that re-arranges, combines, or manipulates sounds asset" (Stevens et al, 2016, pg. 59) This approach allows the user to interact with the visual media and audio.

"Procedural sound" is associated with "synthetic" and "algorithm". To further breakdown the definition of "procedural sounds", the elaboration of "synthetic" and "algorithm" provide another depth of understanding to this term. Synthetic sounds are produced by analog or digital. Analog signal generation are produced by oscillators, analog synthesisers and radiosonic modulations. Digital sound synthesis are produced by techniques based on micro sounds that were difficult or impossible with analog techniques. (Roads, 2015, loc.2100) Algorithm is a set of rules for solving a problem in a finite number of steps. Turning now to distinguish "synthesis" and "algorithm", Farnell believed that "synthesis is usually about sounds produced at the sample and waveform level under careful control, which algorithmic sound tends to refer to the data, like that from a sequencer, which is used to actually control these waveforms" (Farnell, 2007, pg.5)

Fournel introduced five examples of procedural content in games: Sentinel, Elite, DEFCON, Spore and Love. (Fournal, n.d, pg.9) This post focuses on the introduction and procedural sound design of Spore. Spore (Electronic Arts, 2008) is a life simulation, real-time strategy, role-playing and action game developed by Maxis and designed by Will Wright. This game was released on 2008 and the composers of Spore includes Brian Eno, Cliff Martinez and Saul Stokes. The player is allowed to control the development of the pieces through five stages of evolution: Cell, Creature, Tribe, Civilisation, and Space. The gamer could use the Creator tools to make creatures, vehicles, buildings and spaceships. Kent Jolly, the audio director for Maxis/Electronic Arts, stated that Spore has Eno's 1983 album Apollo:Atmospheres and Soundtracks compositions. The music in this game 'will develop and mutate along with their style of play' (Steffen, 2008, Web)

"The system takes variables from user input and uses mathematical algorithms to create control data which subtly changes certain aspects of game-play" (Donnellan, 2010, Web) This helps to enhance the game experience. An example is shown below:

The player is able to customise the mouth, eyes, hands, legs, horn and tails. Different mouth produced different kind of sound.

The video below is another example of procedural sound design. The player was rewarded for his actions and different rewards have different sounds. [5:02 and 6:25] The music was also manipulated subtly based on the new data triggered by the player. [3:21]


The following clip shows the audio changes according to the orientation of the creature. After the player attacked [0:04], the rhythm started to pick up its pace and the creatures started to sound more aggressive. When the player procceded to attack the base [0:50], a sound notification was used and the music starts to change.



In conclusion, procedural sound design is needed to combine, re-arrange and manipulate the different sound assets in the game play for a more engaging and interactive experience.


Bibliography

Bommel, A. (2008) Spore Tribal Stage Part 1 [Internet]. Available from: [Accessed 11 February 2017]. 

Electronic Arts (2008) Spore, computer game, Microsoft Windows, Electronic Arts United States.

Farnell, A. (2007) An introduction to procedural audio and its application in computer games [Internet]. Available from: [Accessed 11 February 2017]. 

Farnell, A. (2010) Designing sound. Cambridge, MA, MIT Press. 

Fournel, N. Games Developers Conference. In: Procedural Audio for Video Games: Are we there yet? Sony Computer Entertainment Europe. Available from: [Accessed 11 February 2017]. 

Hermann, T. (2008) 14th International Conference on Auditory Display. In: Taxnomy and Definitions For Sonification and Auditory Display. Paris, Bielefeld University. Available from: [Accessed 11 February 2017]. 

Roads, C. (2015) Composing electronic music: a new aesthetic. Oxford, Oxford University Press. 

shadowzack (2008) Spore - Creature Stage Part 1 [Internet]. Available from: [Accessed 11 February 2017]. 

D.K. (2008) Spore: The Mouths and the Sounds They make [Internet]. Available from: [Accessed 11 February 2017]. 

Stevens, R. & Raybould, D. (2016) Game audio implementation: a practical guide using the unreal engine. Boca Raton, CRC Press, Taylor & Francis Group, CRC Press is an imprint of the Taylor & Francis Group, an informa Business. 

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