Abstract: The headphone preferably comprises a toroidal seal ring which rests against or surrounds the user's ear and is constituted of a soft, yielding, and preferably elastic material. The seal ring, with the headphone positioned on the head of a user, forms a coupling space between an active diaphragm, actuated by an electroacoustic transducer, and the auditory canal of the user's ear. This coupling space is substantially sealed from the exterior of the headphone, and is formed with at least one opening and preferably several openings each receiving a respective passive oscillatory diaphragm having a definite self-resonance. Each passive diaphragm is associated with a sound path leading therefrom to the open air, to the back side of the active transducer diaphragm, or to acoustically effective cavities. Respective acoustic frictional resistances are associated with each passive diaphragm. The arrangement of the passive diaphragms relative to the active transducer diaphragm may take various forms.

Abstract: The headphone comprises a low frequency transducer system and a high frequency transducer system, with the low frequency transducer system including an electrodynamic transducer. The high frequency transducer system includes an electrostatic transducer, and a supply transformer for the high frequency transducer system is mounted in the housing of the headphone. The two transducer systems are mounted coaxially of each other, with the high frequency transducer system being outwardly of the low frequency transducer system. The high frequency system may have a disc form or may have an annular form and, in the latter case, the inner diameter of the high frequency system corresponds to the outer diameter of the low frequency system which is received in a circular recess of the high frequency system.