Exploring the sounds available from a synthesis algorithm is a complicated process, requiring the user either to spend much time gaining heuristic experience with the algorithm or requiring them to have a deep knowledge of the underlying synthesis algorithms. In this paper we describe a computer system which facilitates a more exploratory approach to sound design, allowing the user to work at the level of the sounds themselves. In this system the synthesis parameters are managed by a genetic algorithm, which is directed by the users' judgements about the sounds in the system. We describe the development of a prototype version of this system, concentrating on an interface to the FOF granular synthesis algorithm from CSound. 1 Introduction Most sound synthesis algorithms are complex, and typically have correspondingly complex interfaces, requiring the specification of many parameters to achieve a desired sound. To produce a sound using such an algorithm typically requires one of two pro...