V43 #6 Jun 1990 - Australian Clay Target Association

KNOW YOUR STATE
STUART BROWNING
As well as being an Executive Committee Member for Tas-
mania. Stuart holds the positlon of the State's Coaching Director.
He has forwarded the following article which proves most inter-
esting. I
DO YOU VALUE YOUR HEARING?
The ear 1s made up of three sections: The outer, the middle and
thelnner.
The outer ear is the part that 1s seen, and it opens into the ear
canal. The eardrum separates the ear canal from the middle ear..
There are three small bones - the hammer, anvil and stirrup
located in the m~ddle ear. These bones transfer sound. The inner
ear conlatns [he bdia?ce nerve end.ngs in the seml.c~rcular canals
and [he heartng nerve enolnqs in !he cochlea which lead to the
bra!r!
Sound vibrations or waves enter the outer ear and strike the eardrum,
causing it to vibrate. The vibrations are then transferred
from the eardrum along the hearing bones to the cochlea, which is
filled wlth fluid. The vibrations cause the liquid to move and stimulate
the tiny nerve endings. The endlngs are attached to make up
the hearlng nerve. The vibrations then become nerve impulses
and go dtrectly to the bratn, where the impulses are interpreted as
sound. The brain can then distinguish the kind of sound - a phone
ringing, machinery in a factory, a gunshot.
If a nolse is too loud. it will begin to kill the nerve endings in the
inner ear. If a person experiences prolonged exposure to loud
noise without hearing protection more nerve endings will be
destroyed, resulttng in hearing loss and ringing.
Sound 1s measured in two ways:
1. dec~beis (dB) and
2. pitch - frequency of sound vibrations per second.
The decibel scale runs from 0 dB, the falntest sound a human ear
can detect, to over 180 dB, which 1s the intensity of sound of a
rocket launch. Most heartng experts agree that continual
exposure to notses of 85 dB or more, wtthout the use ofhearing pro-
tection can be damagtng.
Frequency IS ::~easurec in cycles per sccond ar herl~ (Hz) The
i-..qher the ptich (he c.ghe: :he freq'iency A low pttch such as a
deep voice makes fewer vibrat~ons per second than a h~gh volce.
PAGE 6
Symptoms people begm to notlce IS ringlng In the ears, a condltlon
called Tlnnlt~s For some, this exDerience occurs aiter a
nart~rular r-~ nolse ~~~~~ evoosure ~~~ '---~~~ and dirnin~shes withln hours or davs
Othersare not so lucky and have io l~ve wlih thlscondltton 24 hours
a day. 365 days a year T~nnlrls 1s more nortceabla in quter envlron-
ments. Ttnn~tts 1s permanent and cannot oe corrected
With shooters, because of a head shadow effect, one receives
more noise exposure than the other. Ttierefore the left ear 1s
usually worse for right handed shooters and vice versa for a left
handed shooter.
HOW LOUD IS IT?
Soit whisper 30 dB
Normal conversation 60-70 dB
Vacuum cleaner 70-90 dB
Heavy city traffic 80-90 dB
Lawn mowers 90-105 dB
Screaming child 90-115 dB
Chain saw 100 dB
Thunder clap 120 dB
Shotgun or rifle blast 120 dB
Jet plane at take-off 130-150 dB
~ ~
For personal safety and health, protect your ears from repeated
or continuous exposure to any sound above 80 decibels.
There are only two baslc Types of hearln~ protection ear muffs
and ear plugs Both have advanrages and d.sadvantages Muffs
lend toget In the way of head gear and sometlmescause ~roblems
when mounting the~gun as they contact the comb of the stock.
Plugs are more compact, more comfortable and do not interfere
with head gear or gun stocks.
Hearing loss is insidious, and begins at the higher frequencies
where it may not be noticed at first. But as years go on, it shows up
more and more. This means that a shooter, who has the ability to
hear someone loud and clear talking one to one at age thirty may
well be'into the progressive deterioration which means that at age
forty he may have trouble sorting out what's bemg said in a
crowded room, and at age fifty will need a hearlng aid.
We have all seen older members of gun clubs who are plalnly
suffertng from hearrng loss
Stuart Browning
State Director of Coaching
ZI TRAP GUN
BROWNING
F Grade Trap
30" Medium Rib
in excellent condition.
Top grade timber.
AUSTRALIAN CLAY TARGET NEWS - JUNE 1990