A digital hearing aid, in addition to the three basic components, also has three fundamental factors: it has built-in precise tools that can process sound, address hearing loss at specific frequencies, and suppress unnecessary frequency ranges. This is called frequency compression. For example, it can amplify high-frequency sounds to help the user hear clearly, while loud low-frequency sounds are not amplified excessively. These functions cannot be performed by analog hearing aids. Moreover, most people with hearing loss tend to lose their high-frequency hearing, which is one of the reasons why digital hearing aids are very popular.
