The Receiver
Like the microphone, the RECEIVER is also a transducer, i.e. a device able to transform one form of energy into another. In this case the electrical energy is converted into mechanical energy, i.e. sound, which is sent to the patient’s ear: hence the term “output transducer”.
A differentiation existing inside the receivers is the type of vibrating membrane used: in the case of glasses with bone conduction, the diaphragm consists of a thicker metal bar having to put into vibration not an air mass but the bone structures of the skull.

Earpiece (only for air conduction appliances)
The last piece in the electroacoustic chain, the earpiece is an integral part of the hearing-aid, and as such must meet the following requirements:

• it must be morphologically anatomic, i.e. perfectly fit the auditory canal and the conch of the wearer;
• it must be produced with biocompatible materials, so as not to cause any pathological problems (allergy, irritation, inflammation);
• It must be well tolerated by the wearer, both regarding weight and looks.