Abstract: A coupling element for establishing acoustic connection between a cylindrical hearing aid placed in the concha and a custom made ear plug placed in the auditory canal is formed by a disc-shaped element, which can be rotatably mounted a sound exit nipple on the hearing aid and an angularly bent tube section rotatably mounted on a laterally directed spout on the disc-shaped part. Because the hearing aid housing can rotate about its own axis in the concha and the coupling element can rotate about the nipple of the hearing aid, and because the tube section can rotate about the spout of the disc-shaped part, the tube section may be placed with respect to the auditory canal such that the sound channel in the ear plug can be established by a single, straight bore.

Abstract: An apparatus for use in adjusting a secondary adjustment device of a hearing aid consists of an adaptor that can be so placed on the hearing aid that the adjustment device of the hearing aid becomes coupled to corresponding moving elements on the adaptor. These moving elements are in turn coupled to their respective activation controls on a control desk through respective wires in a bowden cable, enabling the secondary adjustment device of the hearing aid to be adjusted by manipulating the activation controls at the control desk.

Abstract: A hearing aid which can be worn in the ear concha and which contains a microphone, an amplifier, an earphone, a battery and a connection to an ear adapter. All components are mounted in a flat, cylindrical housing (1), whose cover (2) can be rotated around a hollow shaft (6) which acts as the sound inlet channel (4), actuates the on/off switch (8, 9) and carries on its inner side at least one wiper (11) which, in contact with at least one resistive strip (10), acts as a volume control.