Behaviour, Structure and Causality in Procedural Audio - Game Sound Technology and Player Interaction: Concepts and Developments - page 313

Chapter 15
Behaviour, Structure and
Causality in Procedural Audio 1

Andy Farnell
Computer Scientist, UK

AbstrAct

This chapter expands some key concepts and problems in the emerging field of procedural audio. In ad-
dition to historical, philosophical, commercial, and technological themes, it examines why procedural
audio differs from earlier “computer music” and “computer sound”. In particular, the extension of sound
synthesis to the general case of ordinary, everyday objects in a virtual world, and the requirements for
interactivity and real-time computation are examined.

INtrODUctION

and structure which are implied by the identifica-
tion of sound as a branch of dynamics requiring
energetic change.
The task at hand is producing sound for film,
computer games, or other interactive entertainment
applications. This task requires creativity, knowl-
edge and understanding. Creativity in traditional
sound design is directed at capturing, curating and
matching audio data to depicted circumstance,
whereas creation of procedural sound is from
first principles: so it is truly design as opposed
to selection. Insights into process are therefore at
the root of the work.
The end product is sound as code, or sound
objects (Polotti, Papetti, Rocchesso, & Delle,
2001). One must create new digital signal process-

Procedural audio is sound as a process. Instead
of thinking about nouns, we think of verbs, or the
actions that cause sounds. Procedural sound is
also a structural and reasoned, rather than purely
sensible, approach to sound, in which behaviour
supplants identity and we ask not what sound is ,
but what it does .
This chapter follows the publication of De-
signing Sound (Farnell, 2008) in which I lay
foundations for procedural audio, particularly
its use in real-time virtual worlds. Here I would
like to talk about the ideas of behaviour, causality