[. . . ] [. . . ] The NoiseGardTM technology has been developed by Sennheiser and is now used in many cockpits throughout the world. NoiseGardTM against ambient noise NoiseGardTM active noise compensation is based on the principle of cancelling out sound in the low frequency range using counter-sound (inverse phase sound). The NoiseGardTM electronics then create a sound wave, which is phase modified by 180° compared to the noise - which results in the two sound waves almost completely cancelling one another out. ATTENTION: Avoid using headphones with the volume turned up for an extended period of time. [. . . ] [. . . ]