The Art and Science of Building a Hearing Aid

Did you ever wonder how custom hearing aids are manufactured? I didn’t spend a lot of time thinking about it until a recent trip to Phonak’s US headquarters. It was a wonderful visit. I was able to discuss the patient’s perspective with the company’s leadership and audiologists and learn about the work they are doing to improve hearing aid technology.

One of the highlights was touring the company’s 93,000 square foot hearing aid manufacturing facility in Aurora, Illinois. Opened in 2013, the facility employs more than 500 people in varying shifts that allow it to operate 24/7. Here, the company’s custom hearing aids are constructed. The process is a combination of art and science, just like living with hearing loss.

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In my business career, I toured several manufacturing plants in a variety of industries, so I was expecting a loud, mostly automated facility with little room for art in all of the science. I could not have been more wrong. The facility was almost silent, as the employees concentrated on their detailed work across the many stations along the assembly line. Temperature and humidity were carefully controlled to reduce the risk of static electricity, which could wipe out the internal electronic components.

The manufacturing process starts in the mail room where the orders for the day arrive. Thousands of packages are delivered each day, most containing ear impressions that will be used to build someone’s new custom hearing aid. Each order receives a computer tracking number and the real work begins.

The impressions are scanned and digitized into 3-D images, which are then used to design the internal workings of the hearing aids. Using computer aided design, each component of the hearing aid is placed in its virtual shell. While many components fit in a standard location, others shift around depending on the nuances of each impression. This is where the art comes in — balancing functionality with practicality to make sure all the features that the hearing aid wearer desires fit into the very small space provided.

When the computer design is finalized, it is sent for printing. The facility contains more than 20 state-of-the-art 3-D printers which produce a large number of molds per batch. You can see the finished shells fresh off the machine in the photos below.

Once cooled, the shells are removed from the base, and they and their internal components are sent to the assembly area. Here, skilled technicians manually construct the hearing aids, often using tweezers and high-powered microscopes since the components are so small. Once the wiring is complete, the hearing aids are sealed, trimmed and buffed by hand. At this point the aids are fully functioning.

The final step before shipping is quality control. Each hearing aid is programmed and put through a series of tests to make sure it is operating as expected. If functional or cosmetic issues are found, the aids are sent back for retooling. The entire manufacturing process can take several days.

I was impressed with the look and feel of the facility and amazed at the skill of the technicians who are maneuvering so many small and delicate components to create the miracle we call the modern custom fit hearing aid. It was inspiring to see the marriage of art and science applied to creating better hearing for so many people.

If you are interested in learning more about the Aurora Operations Distribution Center (AODC), you can watch the company’s captioned YouTube video describing it here.

Readers, have you ever wondered how custom hearing aids are made?

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13 thoughts on “The Art and Science of Building a Hearing Aid

  1. Great article Shari. I am always fascinated by how things are made, especially in this age of technology and in particular 3D printing. I wonder how much slower the process was without 3D printers before?

    Looking forward, I also imagine they will be setting up a generic assembly line for the new OTC aids where customization would be minimal. It will be interesting to see what they come out with.



  2. Shari,
    Thanks for this interesting report. Like you, I have never really thought about the manufacturing process. It puts the high price of hearing aids into context, even without considering research costs. I have occasionally wondered about R&D, and how difficult it would be to create an aid that would really give better speech discrimination, especially in noise. Because of my former career as a musician I have also wondered about designing an aid that would correct my now poor pitch perception. These are very complex questions, but I still hope for better.



  3. Hey Shari. Over the counter hearing aids have been for mild to moderate hearing loss . Nana has hearing aids thst qualify for modereate to low end severe. This company and others believe you do not have to aids geared to your loss. My old aids age still working at the moment (15 years old) but I have a fear of them dying at any Moment. There is a difference. I do believe it does matter if aids are made for your loss. Since I do not have $6500 ( do not quaudify for care credit) I decided to try Nano . I am impressed. It will work reasonably well for moderate to low end of severe. FYI


  4. I wonder if the subject of telecoils in hearing aids came up?

    Those of us concerned about assistive listening understand that t-coils are vital for wireless listening via hearing loops and neck loops. And we bemoan the unwillingness of manufacturers to build t-coils (costing about $2 each) in all hearing aids when many audiologists fail to explain the t-coil option to consumers, despite laws in some states mandating such education.


  5. Fascinating visit–thanks for sharing! I strongly agree with Jerry, above, re the inclusion of telecoils in ALL hearing aids! The smaller they get, in order to appeal to the ‘vanity’ quotient among potential customers, the less likely telecoils will be included–as you know. Five years ago the stat was that “85%” of all hearing aids contained T-coils. Now, the figure being given out is “70%”. I meet people almost every day who have no idea if their HAs contain telecoils, why they need them, or what to do about it. We need to keep T-coils at the front of the conversation.


    • Amen, Mystuart and Sheri.

      I don’t know where the stat that 85% hearing aids had t-coils five years ago came from, but I’ve recently heard that 81% now have them. In its newest brochures, HLAA would only agree to say that “over 70%” of hearing aids have t-coils. But numbers are really not the issue.

      I believe the percentage is actually rising, chiefly because of consumer education, pressure on audiologists to provide t-coil information, and grassroots advocacy for hearing loops in places of public accommodation by advocates like us. But you’re right that many who have them have no clue how to use them.

      Consumers have a right to make vanity decisions, but they’re also entitled to advice on how to hear best — preferably before being sold a hearing aid. Let’s all ask our audiologists to install hearing loops in their offices.

      Liked by 1 person

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