Sound enters a hearing aid through the microphone. It is processed by the circuitry inside the device and then delivered to a receiver (loudspeaker). The sound enters the wearer's ear canal from the receiver, either directly in the case of a custom style hearing aid or through tubing, which is connected to an earmold in the case of a behind-the-ear hearing aid.
Most hearing aids on the market today use sophisticated digital circuitry. The word digital refers to the method of sound processing. In the case of digital sound processing, the sound is coded mathematically into bits. This level of precision affords the audiologist flexibility to customize the hearing aid to your specific hearing loss requirements.
Like anything else in the world of technology, there is an array of digital hearing aid technology, ranging from basic to advanced. The more sophisticated the technology, the greater the number of features available on the hearing aid.