The Mercedes-Benz Technology Center here in Sindelfingen has twelve high-tech test rigs for testing sound waves, oscillations and vibrations.

One of them is the "exterior noise test chamber". It covers an area of eighteen by twenty-five metres. This makes it bigger than a tennis court. Hundreds of insulating elements made of rock-wool and measuring around a metre wide, cover the walls and ceiling of the hall. They are used to suppress sound reflection. This is where we meet Mercedes engineer Christoph Meier: