Sound Classification in Hearing Aids by the Harmony Search Algorithm - Music-Inspired Harmony Search Algorithm: Theory and Applications - page 173

• A microphone, to convert the input sound into an electric signal

• A number of electronic blocks aiming at compensating the hearing loss.

Among other signal processing functionalities, a proper sound amplifier will
intensify the strength of the signal in which the user is interested (e.g. speech,
in most of the cases)

• A tiny loudspeaker to convert the electrical signal back to sound

• A coupler to the ear canal, usually referred to as an 'ear mold', and

• A battery to provide electric power to the electronic devices of the hearing

instrument.

Fig. 2. Typical structure of a digital hearing aid

Fig. 3. Representation of the functional blocks to be implemented on the digital hearing aid