AN ELECTROACOUSTIC COMMUNICATIONS UNIT

摘要

An electroacoutic communications unit with a receiver transducer in a housin g. The communications unit has accoustic connections both from the front side o f the diaphragm of the transducer and from its rear side to the area inwardly of the face of the unit for engagement with a user's ear as well as to the area outwardly of this engagement face. These four acoustic connections constitut e the four branches of an acoustic balance bridge with the transducer as a generator. This configuration is particularly expedient, as it is hereby possible to reduce the inner air volume in the communications unit behind th e diaphragm of the transducer to a size which is without importance for the si ze of the telephone in practice. Furthermore, variations in the degree of tightness of the engagement of the communications unit with the user's ear will only influence the frequency characteristic to a very limited degree.