Using physical simulation to control movement and interactions between objects in a 3D environment, such as a computer game, has become increasingly common However; this idea has not been extended in a general sense to the audio domain. The audio component of these systems usually comprises of pre-recorded WAV files that are triggered in response to events. We argue that this approach has serious limitations and propose instead that the physical information made available by physics engines provides an opportunity to carry out synthesis of appropriate sounds from scratch. We outline a framework for adding a sound synthesis module to a physics engine and discuss some approaches to implementing this.