How Do Hearing Aids Work?

a hearing aid in a display

It’s easy to assume that devices like hearing aids are simple. They have a microphone to receive sound and a speaker to play it back, but there is a lot more under the surface that makes these devices work properly. We’re going to take a deep dive into the technology behind hearing aids, giving you a much better understanding of how these devices work to improve a person’s hearing. Having an insight into this area can make it much easier to choose the hearing aid that will be best for you.

Sound Input

This process starts with a little bit of external input in the form of sound. A small set of microphones can be found in most hearing aids, enabling the device to pick up noise from more than one direction and effectively measure background noise. These microphones are tiny but extremely sensitive, and this is how they’re able to produce such natural sound.

A huge amount of time and effort goes into calibrating the microphones found in hearing aids, and this is part of the reason that this component is one of the more expensive ones you’ll find inside a hearing aid. Alongside this, they have to be made to extremely tight tolerances, or they simply won’t be able to fit inside the small casing of your hearing aid.

Sound Processing

If a hearing aid was to simply play the audio that it picks up back to the user, they would be almost impossible to use. Background noise has to be ironed out to make sure that you can hear your subject properly, and things like static and feedback also need to be removed. This all has to happen in a fraction of a second.

This is achieved by using a powerful microcontroller that can run sound processing software that has been specifically designed for hearing aids. This is quite similar to the way that sound-canceling headphones work, with the important sounds being highlighted and those that you don’t need to hear squished down. Once the audio has been processed, it will be time to send it to the amplifier.


Removing background noise and audio artifacts is only possible when you lower the volume of the sound being worked with, effectively cutting off the wavelengths that cause the unwanted noise. This leaves the audio quiet and hard to hear, though, and this is why most hearing aids come with a built-in amplifier.

This amplifier will boost the sound signal, making it louder without adding new background noise. Alongside this, the audio signal will also be converted from being a digital signal to an analog one that can be played back by a regular speaker. This process will maintain the clarity of the audio while making it possible for users to change their hearing aid volume without introducing issues like clipping.

Sound Output

Once the sound has been processed, it will finally be time for the user to hear the output. This will be done using a small speaker and plastic mold that directs the sound at the right part of your ear. Despite being small and looking similar to the drivers you find in in-ear headphones, these speakers are usually far more sensitive and can output a very broad range of frequencies clearly and naturally.


Hearing aids can also be equipped with specific features to further your listening experience. From Bluetooth connectivity to directional microphones, your devices will be tailored to your specific needs. This ensures you will get the most clarity when communicating in your daily life.

Audiologists work extremely hard to make sure that their hearing aids produce accurate sound. This is something that can change over time, though, with any type of speaker naturally adapted based on the type of sound that it most commonly plays back. This usually isn’t something that will cause problems but is worth thinking about if your hearing aid is several years old.

Hearing aids are incredible devices that enable people to live a life that would be much harder to come by without them. It’s wrong to assume that they are simple, with most people needing the help of a professional audiologist to use them properly. Here at Wesson Hearing, our dedicated team has the experience to work with hearing aids of all shapes and sizes, making it worth giving us a call at (209) 275-1657 if you’d like to explore your options.