Most motorcyclists understand the effects of a "silent killer"
which follows them every time they enjoy riding their bikes. Unfortunately,
several people still believe the causes of hearing loss are due
to how loud the bike sounds, and/or that it affects only the people
who do not wear full shell helmets. Based on several research studies,
the major contributor to hearing loss in the motorcycle industry
remains the "silent killer" known as "wind noise."
Generically termed as the amount of noise turbulence produced around
the head while the rider is in motion. Its inherited consequences
result in irreversible hearing loss damage over a period of time
when adequate hearing protection is not worn.
Similar to the shooting and aviation industries, if this issue is
not addressed correctly from the beginning the amount of exposure
to the inner ear is compounded every time the rider ventures out
on his/her bike for hours at a time. Constant duration of harmful
level noises gradually force the rider into becoming another statistic
of the "silent killer." To put this in perspective, according
to OSHA's regulation of industrial noise exposure, an average worker
surrounded by levels around 85-90dB for an eight-hour day will not
exceed the limits of exposure time within a 24-hour period of time.
However, when the sound levels exceed 100dB, your exposure time
is reduced to two hours. When sound levels exceed 115dB, your exposure
time is drastically reduced to 15 minutes. This puts riding a bike
into a whole new realm as "wind noise" at highway speeds
can measure up to 110dB, or comparable to a running chainsaw. At
these levels the riders are not only fatiguing themselves physically
from the excess noise exposure, but it also puts them into a position
of needing a hearing aid later in life.
Another common ailment of motorcycle riding is a condition known
as "Temporary Threshold Shift," commonly referred to as
TTS by audiologists and hearing healthcare professionals. TTS is
caused by excessive noise exposure for a duration of time, which
drops your actual acute hearing pattern to a lower level temporarily.
Meaning, your hearing is less than what it was before the initial
exposure. Continuous TTS exposure will result in permanent damage.
Everyone has experienced this phenomenon at one time or another,
whether it is from going to loud dance halls, or concerts, or even
work. Even some of today's movie theatres can cause this to happen,
but this is a specific certainty for motorcyclists who disregard
adequate hearing protection while riding their bike. Riding position
and style of windshield help in preventing "silent killers"
ability to be fully experienced. But even the best helmets on today's
marketplace provide little help when considering "wind noise"
levels at normal highway speeds. Obviously, this factor is increased
in half shell models as well as skullcaps, but the common helmets
used in today's marketplace are designed to fit entirely over the
head providing a snug fit. These types of helmets have the best
attenuation value (reduction in noise) regardless of any airflow
modifications done to the outside. But these helmets still produce
wind noise readings of 110 to 116dB's, from 35mph to highway speeds.
When reflecting back to the comparison chart, 116dB will only be
suitable for 15 minutes of riding a day. Not a lot of time to enjoy
your hobby.... Is it?
Although there are several versions of hearing protection devices
on the market, a custom set of earmolds is still the best answer
in suppressing sound. They provide excellent attenuation values
and are comfortable to wear for extended periods of time. They can
even be molded with high-grade transducers, which allow for stereo
compatibility or communications. We also suggest checking with your
local state officials on the regulations of wearing hearing protection.
Several states have motorcycle laws regarding earplug use. For a
quick reference, see the AMA web pages on State Motorcycle Laws
- http://www.ama-cycle.org
Some more interesting facts
There is no significant difference in wind noise level as a function
of speed, no matter what the helmet brand or model.
Neither the riding position nor the brand or styles of motorcycle
make any significant difference in noise level.
·
Padding inside the helmet, open or closed vents, or added weather
stripping on the helmet to alter flow patterns, does not significantly
alter the noise level in a helmet.
Stopped at a stop light at a busy intersection with your helmet
visor closed produces a sound level of 80-90dB SPL.
When not wearing a helmet, the wind noise at highway speed is nearly
10 times greater than when wearing a full coverage helmet.
Below 30mph, machine, exhaust and environmental noises are heard.
Once speeds exceed approximately 30mph, wind noise dominates completely.
Some helmets resonate at approximately 500Hz, and actually enhance
wind noise.
Legal speeds of 65mph can produce wind noise levels in excess of
108dB, this noise is loud enough to cause TTS in your hearing, tinnitus,
and permanent hearing damage.
