Understanding Your Hearing Aid's Parts and How They Work

Every hearing aid has the same three core parts: a microphone that picks up sound, an amplifier that makes it louder where you need it, and a speaker (receiver) that sends it into your ear. A digital processor manages all three, and external pieces like domes, earmolds, and wax guards get the sound comfortably into your ear canal. Knowing what each part does makes it much easier to troubleshoot problems, talk with your hearing care provider, and keep your hearing aids working well.

Key Takeaways

• All hearing aids contain a microphone, amplifier, and speaker (receiver) to capture and deliver sound.
• External pieces like domes or earmolds vary based on your type of hearing loss and hearing aid style.
• Regular care and timely replacement of small parts improve performance and help your hearing aids last longer.

What Are the Main Parts of a Hearing Aid?

Every hearing aid, whatever its style or size, has three core components, as the National Institute on Deafness and Other Communication Disorders describes:

• Microphone, which picks up the sounds around you
• Amplifier, which increases the strength of the sound
• Speaker (receiver), which sends the amplified sound into your ear

In modern hearing aids, these parts are managed by a digital processor, the brain of the hearing aid. The processor interprets incoming sound and adjusts it in real time to bring out speech, reduce background noise, and match your specific hearing loss. Depending on the model, your hearing aid may also have a telecoil, directional microphones, or Bluetooth built in.

Internal Hearing Aid Components

The parts inside the casing aren't visible, but they're the foundation of how clearly you hear.

Microphone and processor

The microphone usually sits near the top or front of the hearing aid. It picks up the sounds around you and passes them to the processor. Many modern hearing aids have directional microphones, which focus on speech in front of you and turn down noise from behind and beside you.

The digital processor then filters the sound and adjusts it to your hearing needs. Many processors can separate speech from background noise, which makes conversation in noisy places much easier to manage.

Amplifier

The amplifier strengthens the incoming sound. Unlike a volume knob that makes everything louder, a hearing aid boosts mainly the frequencies where you have hearing loss, so voices become clearer without distortion.

The amount of amplification is set to your audiogram, the chart of your hearing across different frequencies, so you get clear, natural sound without over-amplification or discomfort.

Telecoil

Some hearing aids include a telecoil, a small copper coil that picks up magnetic signals from hearing loop systems and some phones. Switch your hearing aid to its telecoil (T) program in a looped theater, place of worship, or service counter, and the sound goes straight into your hearing aid with much less background noise.

Battery or power source

Hearing aids run on one of two power sources:

• Disposable batteries, typically zinc-air, which last from a few days to a couple of weeks depending on battery size and use.
• Rechargeable batteries, often lithium-ion, which you charge each night in a charging case or dock.

The battery sits inside the main body of the hearing aid. Rechargeable models are increasingly popular because they're easy to use and save the cost of buying batteries. Learn more about how rechargeable hearing aids work.

External Hearing Aid Components

The internal parts handle the processing; the external parts deliver the sound comfortably and securely. These differ by hearing aid style and your level of hearing loss.

Dome vs. earmold

Domes and earmolds both sit in your ear and channel sound from the speaker into your ear canal. Which one you use depends on your hearing loss and your hearing aid style.

• Domes are soft, bell-shaped silicone tips that fit on the end of the speaker or tubing. They come in several sizes and styles (open, closed, and double) and are best for mild-to-moderate hearing loss, especially with receiver-in-canal (RIC) and behind-the-ear (BTE) hearing aids.
• Earmolds are custom-molded acrylic or plastic pieces shaped to your ear. Their tight seal lets the hearing aid deliver more amplification without whistling, so they're often used for moderate-to-severe hearing loss. They're also more durable and stay in place better, which helps active users and children.

The right fit matters. A poorly fitting dome or earmold can let sound leak out, cause feedback (whistling), or become uncomfortable over time.

Wax guard

A wax guard is a tiny filter at the tip of the receiver or in the sound outlet that keeps earwax out of the speaker. When it clogs, sound becomes muffled, weak, or cuts out entirely, so a clogged wax guard is one of the most common reasons a hearing aid seems to stop working. They're designed to be replaced at home.

Wire or tubing

Hearing aids that sit behind the ear need a connection to deliver sound into the ear canal:

• A thin wire, used in RIC hearing aids, connects the case behind your ear to a small speaker inside your ear canal.
• A plastic tube, used in traditional BTE hearing aids, channels sound into a dome or earmold.

Both are lightweight and discreet. They may need replacing if they become clogged, cracked, or loose.

Buttons or switches

Many hearing aids have external controls so you can change settings by hand, such as:

• Volume controls
• Program buttons for switching between listening environments
• Bluetooth pairing buttons on some models

Your audiologist can often program these controls to suit your preferences. If a button stops working or gets hard to press, check with your provider.

Shell or case

The shell holds all the internal parts and protects them. It's usually made of hard plastic or another lightweight material, and comes in skin tones or other colors depending on whether you want it to blend in. Whatever the design, it should be durable, easy to clean, and comfortable to wear all day.

How Do Hearing Aid Parts Differ by Style?

Each hearing aid style arranges the same parts differently to balance comfort, visibility, and power. Here's where the key components sit in each type. (For a full comparison of styles, see our guide to types of hearing aids.)

Behind-the-ear (BTE)

BTE hearing aids hold the microphone, amplifier, and battery in a small case behind the ear. Sound travels through a tube to a dome or earmold. This style is durable, easy to handle, and suits a wide range of hearing loss, including severe and profound.

Receiver-in-canal (RIC or RITE)

RIC hearing aids look like BTEs, with one major difference: the receiver (speaker) sits inside the ear canal, connected to the case by a thin wire. Moving the speaker into the ear improves sound quality and shrinks the case behind the ear, making the device more discreet. Audicus's Omni 2 is an example of this style.

In-the-ear (ITE), in-the-canal (ITC), and completely-in-canal (CIC)

In these styles, all the parts (microphone, amplifier, and receiver) are enclosed in a single shell that sits in the ear. ITE hearing aids fill the outer bowl of the ear, ITC aids sit partly in the canal, and CIC aids sit completely inside it. They're less visible, but they can be harder to handle if you have dexterity challenges, and their smaller batteries often run down sooner.

How to Care for Your Hearing Aid's Parts

Most hearing aid problems come from earwax, moisture, or ordinary wear, and a few minutes of daily care prevents many of them.

Wipe your hearing aids every night with a soft, dry cloth, paying attention to:

• The dome or earmold, which collects wax
• The microphone ports, which can trap dust
• The tubing or wire, which can wear over time

Store your hearing aids overnight in a dry, protective case or a hearing aid dehumidifier. Keep them away from water: most models are water-resistant, not waterproof. Our hearing aid cleaning guide walks through it step by step.

If you notice crackling, whistling, or a sudden drop in sound quality, a part probably needs cleaning or replacing. Your hearing care provider can help track down the cause.

When Should You Replace Hearing Aid Parts?

Hearing aids are built to last for years, but some small parts wear out much faster. Replacing them on time prevents bigger problems and keeps your hearing consistent.

Part	When to replace
Domes	Every 2 to 4 months, or sooner if discolored, stiff, or loose
Wax guards	Whenever sound is muffled or cuts in and out
Earmolds	About once a year, or when they no longer fit well
Tubing or wires	When cracked, brittle, or loose
Rechargeable batteries	Every 3 to 5 years, depending on use

You can order domes, wax guards, and other supplies for Audicus hearing aids from the Audicus Supplies page, or see which supplies you'll need after buying hearing aids. If your hearing changes or your hearing aids no longer meet your needs, talk with your hearing specialist about whether it's time to upgrade.

If you're shopping for a new pair, compare Audicus's OTC hearing aids.

The electronics inside a hearing aid last for years; the small parts outside it are what need your attention.

Frequently Asked Questions

What are the main parts of a hearing aid?

The main parts of a hearing aid are the microphone, amplifier, receiver (speaker), battery or power source, and digital processor. Depending on the style, a hearing aid also uses external pieces such as a dome or earmold, a wax guard, and a thin wire or tube to carry sound into the ear.

What's the difference between a dome and an earmold?

A dome is a soft, off-the-shelf silicone tip suited to mild-to-moderate hearing loss, while an earmold is a custom-made piece shaped to your ear and often used for more severe loss. An earmold's tighter seal lets the hearing aid deliver more amplification without whistling.

Can I replace hearing aid parts myself?

Yes, you can replace disposable hearing aid parts like domes, wax guards, and batteries at home. For wires, custom earmolds, or anything inside the hearing aid, it's best to contact your hearing care provider or the manufacturer's repair service.

Why is my hearing aid whistling?

Hearing aid whistling, or feedback, is usually caused by a poor fit, a blocked sound path (often earwax), or a damaged dome or earmold. Cleaning the hearing aid, replacing the dome or wax guard, or trying a different dome size usually fixes it.

How often should I clean or replace hearing aid parts?

Clean your hearing aids every day and check the parts weekly. Replace domes every 2 to 4 months and wax guards whenever sound gets muffled, and contact your provider if sound quality drops or a part is damaged.