The past 100 years has witnessed a considerable amount of research aimed at improving our understanding of the way in which sound behaves in auditoria. However, there remains a need for transferring much of this knowledge into the design process. Ideally, the designer should be able to access this knowledge at all stages of design and thus to ensure the achievement of good acoustical conditions in the finished project. In this paper, a rule based approached to room acoustic design, implemented on a personal computer, is described. All rules are related to relevant research findings and presented in such a way as to leave the designer with sufficient leeway to enable him or her to explore a range of innovative solutions.