A guide to hearing aid parts and controls

What are the parts of a hearing aid?

Hearing aids come in different sizes, shapes, and styles, and your device of choice may depend on your budget and how you live your daily life. However, most types of hearing aids have these essential parts: microphones, amplifiers, speakers, and batteries. Let’s take a look at how each of these parts contributes to better hearing.

Amplifier

Amplifiers make sounds stronger. They receive sound and turn it into an electrical signal, which is then sent to the speaker. Someone’s level of hearing loss determines how much sound and which pitches are amplified. A hearing professional, such as an audiologist, can run a hearing test and use audiograms to ensure a device has the proper amplification.

Battery

The battery powers every function of a hearing aid. Most modern devices use rechargeable lithium-ion batteries or disposable zinc-air button batteries, each with unique advantages.

Rechargeable hearing aids have built-in lithium-ion cells that connect to a charging dock or case through small metal contacts. It’s important to keep these contact points clean and free of debris for efficient charging. A full charge typically lasts at least one day—sometimes up to 30–40 hours, depending on the device, features used, and streaming activity.

Rechargeable batteries generally last three to five years before replacement is needed. This service is usually covered under the device’s warranty and must be performed by the manufacturer or authorized provider, not the user.

Disposable batteries sit behind a small battery door and must be replaced when depleted. People with severe to profound hearing loss often rely on these because they deliver more power than smaller rechargeable designs. Battery size directly affects lifespan—the smaller the cell, the more frequently it needs replacement. Disposable batteries usually last five days to two weeks with average daily use (about 16 hours per day).

To extend the life of any hearing aid battery be sure to wipe down the device and charger with a dry cloth each night, store aids in a cool place away from humidity and direct heat, and charge or replace batteries as recommended by the manufacturer.

Dome

An ear dome is common in receiver-in-canal (RIC) devices instead of an earmold. A silicone dome comes in many sizes, but is small enough to rest within the ear canal and remain invisible. It attaches to the end of the tubing of a hearing aid. Like an earmold, the fit is critical to avoiding sound issues, including feedback.

A daily cleaning with a soft cloth can remove debris and ear wax. You’ll need to replace the dome if it becomes damaged or doesn’t work as it should.

Earmold

Earmolds are custom-fit parts of hearing aids that rest inside the ear canal and are typically recommended for customers with severe hearing loss because they trap the incoming sounds in the ear canal, making the perception of sounds louder. Generally, an ear mold is made of hard acrylic or soft silicone. Its job is to seal the sounds your device sends to your ears. The custom fit is important — you don’t want them to move or fall out.

Earmolds consist of two holes: the vent (which we’ll get to further down) and the sound bore, a channel with an inserted tube. Sounds come out of the sound bore.

To keep the earmolds clean, wipe them with a soft cloth and remove debris from the holes. Some earmolds may also contain wax guards or filters to help prevent the sound bore from becoming blocked.

Ear Hook

Ear hooks are primarily found in behind-the-ear (BTE) hearing aids. They’re clear and plastic with a tube that keeps the device in place by looping over the ear. Ear hooks also connect the device’s body to the speaker.

Microphone

The hearing aid microphone picks up important sound in a user’s environment and relays it to the sound processor and amplifier. Most modern hearing aids feature directional microphones that can distinguish between speech and background noise. This technology helps users focus on the sounds that matter most, even in loud environments like restaurants and crowded parties.

Microphones should be cleaned daily with a brush to prevent debris buildup from things like oil, dust, and hairspray residue.

Speaker (Receiver)

Once the microphone processes the sound and the amplifier enhances it, it reaches your ear through a receiver or speaker. The receiver takes the electrical signal from the amplifier and transforms it into acoustic signals that the ear can hear.

The receiver has a wire that is plugged into the device and serves as a connection to the speaker. The speaker’s place in an ear dome or the earmold varies depending on the model, degree of hearing loss, and customer preferences.

Vent

A vent is a small hole in an earmold, usually found in the lower earmold, allowing air and low-frequency sounds to pass through. This ventilation reduces the feeling of fullness or “plugged ears” (a sensation known as occlusion) and promotes better ear health by allowing moisture to escape.

Vents are most common in hearing aids for mild to moderate hearing loss, as they balance natural hearing with amplified sound. While helpful, the vent size must be customized—too large, and it can cause sound leakage or feedback.

Volume controls

Modern hearing aids can adjust the volume to your surroundings. However, you may change them manually via an app or the device through a button or switch. The manual option can let you toggle between different programs or settings based on your surroundings — such as a loud concert versus a quiet dinner at home for two. You may also be able to increase or decrease the volume. A hearing professional can help you determine your device’s capabilities and how to customize your experience.

Wax guards

People naturally have ear wax, and regularly cleaning your device can help reduce buildup. However, accumulation can make it harder for you to hear and create issues with the hearing aid, such as clogging. Wax guards are small plastic screens that trap wax, debris, and moisture to prevent these challenges from arising. Moreover, wax guards can help prolong the lifespan of a hearing aid. Replace wax filters monthly — or more as needed. These parts may also be called wax filters or traps.

Parts of a receiver-in-canal (RIC) hearing aid

In receiver-in-canal hearing aids, the speaker sits within the ear canal and uses a small wire instead of a tube. These devices have many of the above parts and are most likely to have an ear dome, which suits the smaller nature of these RIC devices. Parts of an RIC hearing aid include:

• Microphones
• Button
• Dome
• Retention tail
• Receiver/Speaker
• Wax guard
• Batteries (disposable or rechargeable)

Parts of a behind-the-ear (BTE) hearing aid

Behind-the-ear hearing aids are typically suitable for any degree of hearing loss but are most commonly used for moderate to profound loss. These models are larger and use a tube, which generally connects to an earmold or dome in the ear canal. The tube rests at the back of the user’s ear, typically on the outside. BTE hearing aids usually have an earmold versus a dome and a hook to keep the device in place and provide a connection to the speaker.

• Microphone
• Amplifier
• Receiver/speaker
• Volume control
• Hook
• Tubing
• Earmold
• Batteries (rechargeable or disposable)

Parts of an in-the-ear (ITE) hearing aid

In-the-ear hearing aids rest entirely within the person’s ear and need a fitting to ensure comfort. The casing is typically made of plastic and contains all or most of the technology. Here’s what an ITE contains:

• Microphone
• Amplifier
• Speaker/receiver
• Battery
• Vent
• Wax guard
• Volume control

Getting the most from your hearing aids

Understanding the different parts of your hearing aid can help you get the most out of your device. Each component — from the microphone and amplifier to the dome and wax guard — plays a vital role in how well you hear and how comfortable the aid feels.

Simple habits like daily cleaning, safe storage, and timely battery or filter changes can prevent issues and extend your device’s life. With proper care and guidance from your trusted audiologist, your hearing aids can deliver clear, reliable sound for years to come.