Ehrig, L.L.EhrigBeer, D.D.Beer2022-03-082022-03-082011https://publica.fraunhofer.de/handle/publica/309515The invention relates to a flat loudspeaker with an emission characteristic which provides a better hearing result in the event that the flat loudspeaker is positioned backwards, wherein a loudspeaker is provided in the housing, and a sound guiding structure is designed such that the sound from the loudspeaker is guided outwards via an acoustic aperture in the housing for an undirected emission.en621006patent20090265905