The buildings of the European Parliament, consisting of several different conference rooms and adjacent to a railway station, proved a real challenge for the acoustic engineers. The combination of an insulating layer to absorb the vibrations from the tracks and a new screening concept block out the noise of the rail traffic inside the building. Using three-dimensional computerized simulations and with the help of reflectors, diffusers and noise absorption panels, rooms with less effective acoustics were transformed into high-quality auditoria where the normal spoken word can be heard clearly from every corner. Close collaboration with the designers finally resulted in a wondrous harmony of acoustics and architecture.