ADA Acoustic Design Ahnert is user of the software packages developed in the own office or by the sister company SDA Software Design Ahnert GmbH . This includes the Simulation Software EASE, which has been constantly further developed by ADA since 1990. As Windows-Version 4.1, this software is actually used in 40 countries. It allows modeling interior rooms and open-air spaces in 3D-representation as well as assigning acoustic properties to the wall and ceiling materials used. By locating sound sources (from a total of approx. 2000 original sources and loudspeakers or Line Arrays produced by 72 manufacturers) in the room or space considered, it is possible to compute acoustic parameters and properties at listener seats or on audience areas (Probe and mapping representation). In the course of further processing it is then possible to make the acoustic properties audible at individual locations. By means of such an auralisation (Module EARS) it is possible to "listen into" the room at a moment at which the room is not yet built or the new sound reinforcement system not yet installed in it. In this connection there was arranged for Version 4.1 (Modul AURA) a cooperation with the Technical University RWTH Aachen, with a view to further facilitating computation of the acoustic parameters. The Measuring Software EASERA developed by SDA is capable of generating diverse excitation signals (All-in-one-Paket) for measuring and thus evaluating the transmission properties of interior rooms and open-air spaces, but also of electrical equipment. The results obtained by a simulation are thus easily verifyable.