An overview of the kinds of damage that can be done
to ears in various noise situations. Reader inquiries
may be directed to "contact us" or by faxing to
719-676-6882.
Monologues in Hearing Health
Sound: How much is too much?
by Max Stnaley Chartrand, M.A.,
DigiCare Hearing Research & Rehabiliation
You go to a rock concert, mega-sporting event, or
some other high decibel activity. At the door, an
usher hands out earplugs to those who want them.
Home safe, right? Wrong! You might partially protect
your ears from the harshest effects of death-defying
sound pressures. But what about the rest of the
body?
Contrary to conventional wisdom, the ears are only
ONE part of the body that needs protecting in such
environments. Not much of a favor has been served,
then, when one wears earplugs to, say, a rock
concert, and then the kidneys, liver, spleen, and
pancreas virtually shut down because of 90 minutes
of blasting at 120 decibels. Just 10 decibels more
would kill the person!
Also, contrary to conventional wisdom, severely
hearing impaired individuals do not have better
physiological tolerance for high sound pressure
levels than normal hearing subjects. The
FDA-mandated warning at SSPL90 at or higher than
132dB means that at that point one is risking
serious damage to their health and well-being.
Certainly, if the ears were the only part of the
body to receive such high-pressure levels, what we
may end up experiencing by escalating sound pressure
levels in hearing aids are:
1)Declining eardrum compliance, where tympanograms
go progressively into shallow A.
2) Thickened scar tissue, requiring more and more
amplification to even realize most comfortable
level. At some point, comfort levels and discomfort
levels. coincide, where one no longer has ANY
dynamic range.
3) Destruction of the ganglia cells of the cochlea
and auditory nerve.
4) Diplacusis, or cochlear distortions at high
amplification levels so that the signal being heard
in one ear is totally different than the signal in
the other ear.
5) Because of amplification-induced noise damage, a
given ear may not be able to benefit from cochlear
implantation when one finally reaches candidacy
criteria.
6) Other damage may occur, including at the central
auditory level.
Professionals and patients should be aware of these
limitations, and resist the temptation of
over-reaching with more and more amplification.
Here are some typical situations where one should be
“en guarde” and ready to advise management in the
goal of achieving safe sound pressure levels in
various public situations:
1) Movie theatres typically, according to
measurements made by the author, blast their feature
productions at about 95-100dBSPL on the C-weighted
scale. This far exceeds OSHA regulations for
employees in the workplace, and should be considered
a serious public health threat. If you attend such a
movie, you should immediately make management aware
that they are breaking the law and need to reduce
average sound levels to 85dB or less.
2) Auto stereo firms routinely exceed safe sound
pressures, and tend to glorify the higher decibels
with slick advertising and pop culture. The public
should rise up against this assault, primarily on
the young, and demand that safety standards be
observed.
3) Mega-sporting events, such as drag races, or even
football, etc, far exceed safe sound levels. Changes
in stadium/facility design, plus reduction of
broadcasting public address systems can go far in
making these situations safer to the public health.
4) Rock concerts that broadcast unsafe sound levels
should be shut down and banned from the community.
5) Most speedboats and large motorcycles far exceed
safe sound pressure levels, and should be required
to be muffled to a safe level or banned from the
public thoroughfares.
6) Large lawnmowers and some chainsaws also exceed
what is safe for human ears. It should be a
requirement of their use to wear earplugs.
7) Airport noise has become a menace to nearby
neighborhoods, causing sleep deprivation,
neurological and physical illness, and, of course,
hearing loss. Since these are regulated by national
regulatory agencies, it is imperative that uniform
standards of sound control be implemented. Since the
worst sound pressures occur below 500Hz (very low
frequencies), such standards should be set on the
C-weighted scale, not the current A-weighted scale.
Ignorance of the above does not minimize the danger
to the public health, nor the lasting damage to
exposed individuals. Millions of Americans are
suffering a number of ailments as a result of the
above assaults on their bodies:
*Permanent hearing loss
*Permanent Tinnitus (ringing of the ears)
*Increases in tendency toward diabetes mellitus II
and renal failure
*Increases in liver disease
*Increases in cardiovascular disease
*Brain damage and dementias of all kinds
*Neurological disorders of all types
Below is a chart of commonly occurring sounds and
their respective sound pressure levels.
ESTMATED SOUND PRESSURES IN SPL dB IN VARIOUS SOUND
ENVIRONMENTS:
140dB/30 meters from jet aircraft during take-off
(Eventual Deafness, Brain Damage Assured)
130dB/Threshold of pain, absolute cellular limit of
human body (Eventual Deafness, Brain Damage)
120dB/Rock Concert, Dragstrip (Permanent Hearing
Loss assured in mids and highs)
110dB/Chainsaw (Permanent Hearing Loss Assured in
High Frequencies)
100dB/Movie theatre, discoteque, night club (Future
Loss assured in High Frequencies)
90dB/ Lawnmower, speedboat, motorcycle (High
Frequency Loss without ear protection)
80dB/Curbside on busy street
70dB/Cocktail party, restaurant noise
60dB/Conversational speech
50dB/Daytime home environment
40dB/Nighttime home environment
30dB/Sound booth, anechoic television studio
20dB/Recording studio
10dB/Human hearing threshold average
0dB/Zero SPL, level at which most of animal kingdom
hears
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