How Do Hearing Aids Work?

How do Hearing Aids Work?

In Hearing Aids by Bary E. Williams Au.D.

Hearing aids are amazing devices that have been around for quite some time. Although the basic explanation for hearing devices has not changed, the details “under the hood” have transformed almost entirely. The earliest hearing devices developed along with miniature electronics, making it possible to fit microphones, amplifiers, and speakers inside your ear. As more and more people adopted the technology, they desired units that fit more inconspicuously in the ears, and hearing devices became smaller and smaller. The latest models can fit entirely in the ear canal, out of sight to the naked eye! Let’s take this opportunity to better understand how hearing devices work. Though you don’t need to understand all the details of new hearing aid functionality, it can come in handy if you find yourself in need of new hearing devices or repairs. 


Acoustic Hearing Amplification

The first hearing devices used a basic process to transform soundwaves into something that people with hearing impairment would be able to understand. A microphone was placed into the air, vibrating with the pressure of soundwaves in the air. Those variations in pressure were transformed into an electrical impulse by a receiver. The amplifier takes that electrical impulse and raises the amplitude, or volume, of the entire signal. With this louder electrical signal in place, the speaker transforms the electrical signal back into acoustic energy, vibrating the air particles that hit the eardrum at a more powerful level. 


This process includes two phases of transduction, converting acoustic energy into electricity and then converting that electricity back into acoustic energy. This process was a magnificent innovation! Now, the acoustic waves were able to become something loud enough for the ears to hear, even when they had experienced hearing loss. However, this technology came with some limitations. It was not yet possible to process the audio signal or to transform it other than to make everything louder. When the signal was raised in amplitude, that included all the background noise, as well. Many people found it difficult to understand people speaking in a room, even though the volume was turned up. 


Digital Signal Processing

Most of today’s hearing aids have another crucial step in the process. Although they continue to use microphones and receivers to convert acoustic energy into electricity, that electrical impulse is also converted into a digital signal in binary code. With digital processing, it is now possible to transform the audio signal before it is amplified back into the speaker and into the ear. 


Crucially, this transformation makes it possible to lower the sound of background noise and to raise the sounds of voices. The possibilities of digital signal processing go far beyond this one crucial transformation, however. Voice recognition makes it possible to amplify the sound of the voice closest to you, while placing other voices in the quieter level, along with background noise. Each sonic environment has its unique quirks and oddities, so digital processing makes it possible to analyze each environment and to accentuate those sounds that are needed by the individual listener. 


Working in concert with the audiogram, a report on an individual’s hearing ability, these devices can now amplify the sounds that are difficult to hear while keeping other sounds at a level that will not cause further damage. When coupled with Bluetooth connectivity, these settings can be modified from an app on a smartphone. If a person walks into a new sonic environment with unique features, the settings on the app can bring down certain sounds while raising others. These settings can be saved, as well, making it possible to quickly customize the hearing assistance you receive in any space. 


With these many innovations to hearing aid technology, many people continue to imagine that they work like old models. On the contrary, the latest technology can do more than you might imagine was possible! 


If you are ready to embark on the path toward hearing assistance, keep in mind that the technology has come a long way from the old hearing devices that offered loud background noise and sometimes gave off whistling feedback. Don’t hesitate to make your appointment for an exam, and you can get to know how much is possible in hearing assistance today.

Bary E. Williams Au.D.
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