Physikalisch-Technische Bundesanstalt

The hearing protectors most sophisti- cated from the technological point of view are reserved for pilots. In a certain way their electronic anti-noise earphones actively suppress the noise by taking countermeasures against the residual noise in phase opposition. The fact that airlines, construction firms and others must reach deep in their pockets to ensure the safety of their employees is explained not only by the material and the sophisticated technology but also by the requirement to comply with the standards, which is time-consuming and expensive. For statistical reasons, 16 test persons are provided for the tests. The PTB works on a simplification of this procedure. The most important coworker for this is the dummy head. Its ear accommodates a microphone changing noise into electrical voltage. This allows the effectiveness of hearing protectors to be objectively assessed.