Hearing Aid Ear Molds—General Information
Ear molds come in many sizes and shapes. In addition they have
evolved from the large earphones of years ago to the almost invisible
ear molds of today.
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Example of an early Hearing Aid Custom Ear
Mold
Click on the "Miscellaneous" button
(on the left), then on "Ear Molds" to see the details of these and other
hearing aid ear molds. |
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In the early days of hearing aids, many of the
carbon hearing aids used earphones that were held on the ear by a headband
(see right).
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Other early hearing aids had earphones that were handheld, either with or without a handle.
(The picture at the right shows one of these hand-held handle models.)
Because these early
hearing aids produced little amplification, feedback was not of great
concern and the hearing aids were usually positioned far away from the
ear.
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With the development of the smaller receiver-type earphone, the headband was no longer practical, and other ways of
attaching these to the ear became necessary. Some were held in place
with clips that went over the outer ear (see right). |
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However, most employed some sort of ear plug. These early ear plugs were
usually some sort of stock mold (see example at right), and often came
in varying sizes to suit different size ears. |
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With the advent of the vacuum tube hearing aid,
more amplification became available to treat hearing loss. Thus it became
important to provide a greater seal in the ear canal to prevent acoustic
feedback.
It is difficult now to pinpoint when the first
custom-fitted ear molds (right) came into use, but patent number 1,893,474 was
filed by a Hugo Lieber for the Sonotone Corporation in 1931. The
patent was granted in January 1933. The patent claims to use a flexible
material such as soft rubber that will mold itself to the shape of the
ear.
This museum includes two of these ear molds (including patent number).
However, these have now hardened so that it is difficult to
determine the exact nature of the material used.
The very early ear molds came in one color—black—and appear to have been molded from some composition-type plastic
material.
Today, there are many styles and colors of ear molds for use
with modern hearing aids. In fact, there is almost as much science
involved in designing ear molds as there is in designing
hearing aids.
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This museum includes a number of these earlier
ear molds used on vacuum tube and later on transistor body hearing aids
(right). |
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It also includes a number of the more modern styles of ear molds that
were used on eyeglass and behind-the-ear hearing aids. These come in
various types and
shapes.
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