Just the Basics – Ears

 

We experience our world through our five senses – Touch, Taste, Smell, Sight and Hearing. They allow our bodies to orient themselves, to protect themselves and provide a defined connection to the world and the people around us. Without them – we are but a bag of meat. With them . . . . I’m “Bill”.

The loss of any one of them diminishes our level of integration. A blind person loses the ability to identify people, places or things by “eye” so they will switch to identification by sound or smell or touch.

An individual who has lost the sense of touch – perhaps through stroke or accident – relies much more heavily on sight to determine their physical location and orientation.

A loss of smell affects our ability to taste as well – creating a bland and “grey” world as we take nourishment while losing the enjoyment of varied tastes.

Finally – our sense of sound allows us to identify friend or foe, enjoy the melody of our favorite song or the voice of the one we love.

As shooters – we place two of our senses in harm’s way every time we visit the shooting range, our sight and our hearing.

We’ve discussed the protection of our sight in the past.    A malfunctioning weapon, an unfortunate ricochet, an errant casing ejected from our weapon can easily damage our sight. “Eyes” are simply a must EVERY TIME YOU STEP ON THE RANGE!!

So let’s chat about our hearing. A quick review of just how we hear might be useful.

The Ear Flap is that combination of skin and cartilage that we typically call our “ear”. Yet, it is but a small part of the overall sensor. Its primary purpose is to gather sound waves and funnel them down the Ear Canal.

The Ear Canal is a channel to the primary hearing sensor components – the Ear Drum, the Hammer, the Anvil and the Stirrup. These are very fragile components and during the development of our bodies, they migrated deep into our skull – protected by skin and fat and muscle and bone. The combination of the Ear Flap and Ear Canal insure that the gathered sounds find their way to these sensors.

As the sound waves travel down the Ear Canal they encounter the Ear Drum creating vibrations in this thin, taught membrane of skin. This is one component that can become damaged over time by repeated exposure to high levels of sound, by repeated infection or by rapid changes in pressure.

Attached to the opposite of the Ear Drum is the Hammer. It transfers the physical vibration of the Ear Drum to the Anvil which then transfers it to the Stirrup. Finally, the Stirrup is attached to the Cochlea. This is a fluid filled sensor with an attached nerve bundle – the Auditory Nerve. As the vibrations of the Ear Drum are transferred through the Stirrup the fluid that fills the Cochlea receive these vibrations. They are detected by the Auditory Nerve and transferred to the brain for interpretation and final conversion to the “sounds” that we “hear”. The Cochlea performs one additional function for us – it provides us with “balance”. There are small hairs – cilia – that line the inside of the Cochlea. As we move, the fluid within the Cochlea also moves inducing motion of the cilia. This movement is also captured by the Auditory Nerve that is also transferred to the brain for interpretation of “which way is up”.

You’ll note that the components “inside” of the Ear Drum are a “sealed” system. This means that the pressure from one side of the Ear Drum to the other can encounter significant differences. Think how your ears “pop” as you rise in an aircraft. The differential pressure between the “outside” and the “inside” is increasing. Yawning or swallowing or chewing gum act to equalize this pressure. What really happens is that your Eustachian Tube is used to equalize this pressure through your open mouth. This is a protection your body provides to insure that your Ear Drum doesn’t rupture during a rapid change in pressure.

So now that we have reviewed how we hear – how do we lose this ability??

Well – illness, disease and age are common causes of hearing loss. However, as shooters we are at additional risk of hearing loss through repeated exposure to high levels of noise. For comparison – let’s look as some typical noises and their “levels” – typically measured in a unit-of-measure called the “db”.

Painful Noise:
150 dB = Rock Concerts at Peak
140 dB = Firearms, Air-Raid Siren, Jet Engine
130 dB = Jackhammer
120 dB = Jet Plane Take-off, Car Stereo, Band Practice
Extremely loud:
110 dB = Machinery, Model Airplanes
100 dB = Snowmobile, Chain saw, Pneumatic Drill
90 dB = Lawnmower, Shop Tools, Truck Traffic, Subway
Very loud:
80 dB = Alarm Clock, Busy Street
70 dB = Vacuum Cleaner
60 dB = Conversation, Dishwasher
Moderate:
50 dB = Moderate Rainfall
40 dB = Quiet room
Faint:
30 dB = Whisper, Quiet Library

As you can see – most of the time the average sound levels around us rest in the 50-60 db levels. Short duration elevations – while possible painful – will have little long-term effect on our ability to hear. However, frequent or prolonged levels above 70 db provide a prime opportunity for hearing loss. For those of us who make frequent trips to the range run a real risk of severe and permanent hearing loss. Hence the frequent cry heard on shooting ranges . . . .

“EARS!!!”

“Ears” will typically consist of three types of hearing protection:

Simple foam plugs. These are pushed past the Ear Flap and into the Ear Canal. Their simple purpose is to absorb some of the high-amplitude sound waves and attenuate their level before they reach the Ear Drum and damage it. These are cheap, usually “OK” for a single use but should not be considered as a long-term solution.

Ear Muffs surround the Ear Flap. They are filled with sound-dampening foam and act to attenuate the sound before it reaches the Ear Flap. Variations on this type of hearing protection will provide you with the best long-term solution for hearing protection on the shooting range. And, for very large caliber weapons, a combination of a simple Foam Plug AND Ear Muffs will go a long way to insure you will be hearing just fine well into the future.

Amplified Ear Muffs are the best of both worlds. They contain an electronic system that uses external microphones to pick up the conversations of those around you and yet, at the first indication of a gunshot, the electronically turn off the microphones and provide you a full level of protection for your hearing. I find their only downfall is that I consistently forget to turn off the amplifiers in them and I drain the batteries. Still, they are great for the range when you want to carry on a conversation without having to remove your ear protection to hear the other person.

There’s a reason everyone hears “EARS!!!” on the range – take care of your hearing. Once it’s gone . . . . it’s gone!