Understanding the various parts of a hearing aid

By | October 14, 2019

Today’s hearing aids are a lot like mini-computers for your ears. And although you don’t necessarily need to understand how the technology works, it’s always a good idea to have a basic understanding of the various parts so you can troubleshoot if a problem should arise.

The parts of a hearing aid

In that spirit, the following components are parts of a behind-the-ear (BTE) hearing aid, the most common type of hearing aid. (Smaller, fully in-the-ear hearing aids work similarly, yet with all the parts contained in just one small device.)

If you’re not sure what kind of hearing aid you have, see more on typical types and styles of hearing aids

Internal parts of a hearing aid

The largest part of your device is the body of the hearing aid, which sits behind your ear. The hard plastic casing houses two important components:

  • Microphone The microphone picks up sound and sends it to the amplifier. With today’s technology, some hearing aid microphone processors are so sophisticated, they can distinguish between speech and background noise, making it easier for the user to understand conversation in noisy environments.
  • Amplifier The amplifier converts sound into an electrical signal and sends it to a receiver/speaker. The power of the amplification varies depending upon the severity of the user’s hearing loss—a diagnosis that can only be made after receiving a thorough hearing evaluation by a qualified hearing healthcare professional.

Most manufacturers recommend you wipe your hearing aids with a soft, dry cloth before putting them away for the night. This helps keep the microphone screen clean, free of debris and working properly. Storing the devices in a dehumidifier each night can also help dry excess moisture and extend the life of the device.

On/off switch

It may sound silly to explain this basic function but, believe it or not, it’s a common reason hearing aid users think their devices aren’t working properly. In behind-the-ear models, this switch is located on the casing that fits behind your ear. If your hearing aid isn’t working, check to make sure it’s turned on. It’s also a good idea to switch your hearing aids off when you’re not wearing them.

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Ear hook

Just like your eyeglass frames, your hearing aid curves gently over the outside of your ear. This hook, sometimes called an “elbow,” connects the microphone and amplifier casing to the tubing and earmold or dome that fits inside your ear canal. It’s natural for this part of your hearing aid to wear out and need replacement as perspiration and body oils break down the plastic. Wiping the ear hook thoroughly with a soft cloth or tissue will prolong its life.

It’s important to make sure the ear hook fits snugly but not uncomfortably on your ear and that it’s connected securely to the casing and tubing. Your audiologist or hearing center professional can help determine the best fit for you.

Connecting tubing

The plastic tubing that fits onto the end of the ear hook transmits the electronic sound from the microphone into the ear mold or dome. The length of this tubing varies according to the make and model of your hearing aid and can be adjusted for the best fit. Like the ear hook, these tubes are made of plastic and will likely need replacement before your hearing aid wears out. Be sure to inspect these tubes daily to make sure they’re securely fastened to the ear hook and ear mold as well as for signs of breaking or splitting. Your hearing care professional will help you select the correct length of tubing depending on the size of your ears. 


After sound has been processed through a microphone and amplified to your specific hearing needs, the sound must be delivered to into your ear. That’s the job of the receiver, also known as the speaker. Once the speaker receives the electrical signal from the amplifier, it converts it back into acoustic energy (sound).

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The receiver/speaker is typically housed in either an ear dome or the earmold, depending on your severity of hearing loss and lifestyle preferences:


Hearing aid with dome
Domes are not visible when worn
properly in the ear.

If you have mild to moderate hearing loss, such as is often the case with age-related hearing loss, your hearing aid probably comes with a dome instead of an earmold. Domes are small, bell- or mushroom-shaped silicone pieces that attach to the end of hearing aid tubing and fit deep in the ear canal. They come in different shapes and sizes to accommodate the unique twists and turns of each person’s ear canal—your hearing care professional will help you pick the right size. A poorly fitting dome can mean sound escapes and creates feedback, so getting the right-sized dome is really important.

Domes are easily cleaned by wiping with a soft cloth each night. They may come with earwax guards that need regular changing, too. Inspect domes daily for signs of wear and to make sure they are securely attached to the tubing. Domes are easy and inexpensive to replace if you experience any problems.


Hearing aid with an earmold
The clear earmold sits inside
the ear.

These form-fitting plastic or acrylic components fit snugly inside your ear canal and concha bowl (the outer ear closest to your ear canal) to provide an acoustic seal for the electronic sound your speaker is piping inside. The shape and fit of your earmold depends upon the model of hearing aid you’ve chosen and the severity of your hearing loss. Earmolds are made by taking an impression of the ear using a special pliable material.

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Earmolds are typically recommended for those with severe to profound hearing loss because they provide the most powerful amplification, and prevent sound from escaping. Again, a proper fit is important to avoid feedback.

Battery compartment

In most models, the battery compartment is located close to the on/off switch on the casing that fits behind your ear. Most manufacturers recommend you remove the batteries and keep this compartment open each night, to allow any accumulated moisture to evaporate.

The average lifespan of a disposable hearing aid battery ranges anywhere from 3 to 20 days. If your hearing aid isn’t working properly, check to make sure your battery is inserted properly. If that doesn’t work (and you’ve turned the unit on!), try inserting a new battery.

Speaking of batteries, many devices now run instead on rechargeable batteries. To keep rechargeable units running properly, be sure to recharge them each night. Current lithium ion batteries hold a charge for 30 hours and last about five years before they need to be replaced. 

Hearing aids are designed to wear daily

Hearing aids can only help you hear if you wear them as prescribed. Hearing is a brain function. By continuing to channel sound signals to the brain, hearing aids help your brain continue to understand sounds they might forget without the help of amplification.

If you have devices that don’t fit properly, emit feedback or aren’t strong enough for your hearing loss, talk to your hearing healthcare professional. If you need assistance finding a hearing care center in your community, visit our online directory of consumer-reviewed clinics.

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