Using a hearing protective device, feedback from the surroundings is of importance. Three aspects to be considered is the ability to communicate orally, the possibility to localize sound sources and to obtain a natural impression of the sounding environment. This could only be achieved by using a protective device that allow acoustic feedback, typically by a pair of microphones attached to the cup of each ear. The microphone signal is fed via an amplifier and an electronic compressor, that limit the amplitude of the signal fed to the loud speakers inside the cups. Typical problems with this type of solution are that the signals received by the two ears are distorted so much that sound localisation is difficult and that the sound is perceived unnatural. The objective of the project is to optimise the cup geometry especially where the microphones are mounted, and by that improve sound localisation and minimise the amplification of non-important weak sounds like the foot step of the user