Ear protecting device with a sealing section for acoustically sealing the meatus of a human, includes a sound generator with a sound outlet for being directed toward the user meatus; an inner microphone with a sound inlet from the meatus, arranged for measuring the resulting sound field in the meatus; connected to an electronics unit including a sound analyser coupled to the inner microphone, for analyzing sound characteristics of the resulting sound field in the meatus, producing analyzed sound characteristics; storing part in the electronics unit for storing measured predetermined sound characteristics of a properly functioning ear protecting device; a comparing part in the electronics unit for comparing the inner microphone analyzed sound characteristics with the stored measured predetermined sound characteristics; indicating part coupled to the comparing part for being activated if the analyzed sound characteristics differ significantly from the predetermined sound characteristics.