Brochure
Specialized Hearing Protectors
Musician’s Earplugs
Certain earplugs are designed for moderate noise reduction and
better sound quality (more uniform attenuation across the range
of frequencies). For many sound exposures such as live music,
public events, and transportation, these devices provide the
needed protection, while making listening easier and more
enjoyable. The effect with these earplugs can be compared to
wearing medium neutral-gray sunglasses instead of very dark
color-tinted lenses that dramatically change one’s perception. The
Professional Musician E•A•R
®
Plug is one such product. Special types
of custom earmolds also provide this feature.
Custom Molded Earplugs
Earplugs can be made by taking a custom impression of the earcanal
using a material with the consistency of thick honey. These can be
very comfortable and are suitable for use for hearing aids and
some specialized earplugs. However, for the simple purpose
of providing noise reduction, they offer little that other types
of earplugs cannot provide at a lower cost. Although they are
“customized,” their acoustic seal can be compromised because
they require a precise impression and must t exactly. For
maximum protection, and equivalent and sometimes better comfort,
a foam earplug is usually preferred.
Electronic Earmuffs
Some earmuffs use a microphone embedded in the earcup to pickup
sounds and transmit them through the earmuff to an earphone
inside. This allows better hearing at low sound levels without
the need to remove the device, while still providing sufcient
protection at higher sound levels. Typically the electronics in the
muff limit the amplied sound to a predetermined safe value such
as less than 85 dBA. These muffs can be excellent for use while
hunting or on the ring line, and for those with a mild hearing loss
they can actually amplify sounds, thus making it easier to hear.
Active Noise Reduction (ANR)
Today it is possible to use sound to cancel sound. A microphone within
the earmuff detects the sound passing through the cup walls and sends
that signal through circuitry to generate an anti-phase version that
is rebroadcast through a speaker in the cup. The result is sound
cancellation, but due to physical limitations this process only works
well in the lower frequencies, middle C and lower. This is effective
in certain military situations, and in general aviation, especially when
the devices also include communications. The principal consumer
application is reduction of nuisance noise such as experienced while
traveling. An ANR earmuff, which also plugs into an earphone jack
on entertainment devices, can provide balanced noise reduction while
simultaneously permitting listening to music or movies.
Your Hearing How it works and how we measure it
How We Hear
Healthy inner-ear nerves (hair cells) are the key to good hearing.
Although some die off naturally as you age, many more are killed
early if your ears aren’t protected from harmful noise.
The outer ear collects and
funnels sound waves along
the earcanal to the eardrum.
The middle ear contains a
chain of three tiny bones, called
ossicles, which link the eardrum
to the inner ear. When sound
waves strike the eardrum, the
ossicles conduct the vibrations to
the cochlea in the inner ear.
Hair cells within
the cochlea of the
inner ear respond
to vibrations
by generating
nerve (electrical)
impulses. The
brain interprets
these as sound.
Measuring Hearing
Hearing is measured by a professional with an audiometer that sends tones to each ear
through earphones. You listen carefully and respond each time you hear a tone. The levels
at which you can barely hear the tones are your hearing threshold levels.
Your thresholds (measured in decibels) are recorded on a chart called an audiogram, for
tones at different pitches or frequencies (measured in “Hertz,” which is a special term
for cycles/second). Normal thresholds fall within the unshaded area on the chart. When
hearing loss occurs the thresholds fall into the shaded areas, meaning sounds must be
increased in level for you to hear them.
It is a good idea to have a complete hearing
evaluation even if you don’t suspect a
hearing problem. This gives you a baseline
against which to compare future audiograms
if problems occur. Professionals suggest
evaluations every 10 years; more often for
those over 50. If you anticipate regular
exposure to high-level noise, for example
if you are an avid recreational shooter, you
may wish to obtain more frequent tests
until you can assure that your hearing is
stable. Unusual changes would alert you
and your hearing specialist (audiologist or
otolaryngologist) to look for noise-related
(inadequate or improperly tted protection)
or medical causes before it’s too late.
Degrees of hearing loss
–10
0
10
20
30
40
50
60
70
80
90
100
500 1000 2000 3000 4000 6000
FREQUENCY, HERTZ
HEARING THRESHOLD LEVEL, dB
SLIGHT
MODERATE
SEVERE
low pitched
sounds
high pitched
sounds
Normal Hearing
Hearing
Impairment