Time-based Environment Engine The LISTEN project I participated in during its running time from 2001-2003 was concerned with the idea of the Audio-Augmented Environment: Visitors to AAEs wear motion-tracked, wireless headphones that allow the augmentation of the physical space with virtual sound sources. At the same time, the content presented to visitor could be adapted and attached to the navigation of the user within the space, the behavior both of the position and the orientation of the visitor's head. The collaborating institutions were Fraunhofer IMK, IRCAM in Paris, AKG Acoustics, and TU-Vienna, Austria as well as the Kunstmuseum in Bonn. My main contribution was the coordination of the production of a series of prototypes that transformed the conceptual ideas of LISTEN to a setting of applied media in a museum context. The idea I contributed and pushed in this collaboration was to create an immersive experience that would adapt to the position and behaviour of the visitor and combined means of expressions derived from radio drama regarding speech and soundscapes with specific uses of sound in this interactive context. To enable the adaption of complex audio presentations to the random navigation of a visitor, I developped and implemented a Time-Based Environment Engine in the languages Scheme and C++. More on the MackeLabor in German (includes a complete credit list).