Hearing Blog
Woman showing different hearing aid shells

A Guide to Hearing Aid Shells

Published 06-08-2019
Last Updated 18-09-2019

Heading into an audiologist’s office to get fitted for new hearing aids? Take a seat; they’ll make a shell. Here’s a breakdown on the steps that go into creating each pair of hearing aid shells.
Written by Annie L. Messmer, Doctor of Audiology

Hearing aid manufacturers utilize computer-aided manufacturing to craft hearing aids that fit each wearer perfectly. This technology turns the impressions of your ears into 3D computer models, which then serve as the basis for making the shells or earmolds.

If you’ve ever seen a 3D printer at work, then you already have an idea of how a hearing shell is created. A machine uses the data from a 3-dimensional blueprint to create a model of your hearing aid shell customized to your hearing canal. The shell is made layer by layer, which serves as the external basis for your hearing aid. Afterwards, the electronic components are added and your new hearing aids are soon on their way back to your hearing professional in order to get ready for your fitting.

The importance of customization

The exact size and shape of your hearing aid shell may differ depending on the type of hearing aid you wear, the degree of hearing loss you have, and the size and shape of your ear. It’s extremely important that your hearing aid shell fits properly inside your ear to give you a comfortable fit and reduce the chance of it falling out.

Different hearing aids have different sized shells based on their intended purpose and location in/on the ear. These can range from completely-in-canal (CIC), in-the-ear (ITE), behind-the-ear (BTE), or in-the-canal (ITC). Click here to learn more about hearing aid types.

Getting the right fit for you

In order to provide a truly custom fit for your hearing aids, your hearing care professional will need to take impressions after inspecting your ears, verifying the health of your ears, and inserting a mold that will provide the manufacturer with the 3D model.

These molds of your ear canal are created through an easy, painless process. Your audiologist will first inspect your ear canals with an instrument called an otoscope.

Your hearing care professional will take the 3D mold, or impression, using a silicone-based material that hardens inside your ear. This process is harmless and involves three steps:

  • First, a little separator called an otoblock is inserted into your ear to prevent the impression material from coming too close to your eardrum.
  • Next, the impression material is injected into your ears. Your ears will likely feel blocked as the material is injected and hardens inside your ears. It’s a good idea to make chewing motions or open and close your mouth repeatedly during this process. Once the material is hardened, your hearing care professional will remove it from your ear.
  • Finally, he or she will inspect the impression to make sure it doesn’t have any holes, gaps, or imperfections that could affect how your hearing aid is made.
Over time, hearing aids have gotten significantly smaller and more powerful. The components and technology to make this possible are typically enclosed in a plastic housing called a "shell." This shell, just like the shell that goes around the tortoise, protects the sophisticated electronics within.

The hearing aid fitting is an important step in the adjustment period. Modern models allow for easier, more precise sound discernment, which can be housed in shells that are smaller and more discreet than ever before.

Start by having a conversation with your local certified hearing professional to have your hearing evaluated and discuss the available hearing loss solutions available for your lifestyle and budget. 

bloom™ hearing specialists have a network of hearing care clinics throughout Australia. We help hard of hearing individuals regain their sense of hearing. Take action to schedule an appointment or see if we have a clinic near your zip code

About the Author

Annie L. Messmer, Au.D.
Dr. Annie Messmer is a certified audiologist with a degree from Northwestern University and over 10 years of experience working with patients of all ages. She has also trained numerous hearing care professionals on audiology best practices and the latest hearing technology.