How safe is your hearing from damage? It’s a question you should ask yourself from time to time if you’re an avid shooter. Chances are that you are not as safe from hearing damage and hearing loss as you think. Part of the problem is a lack of understanding as to what constitutes dangerous noise levels. Another issue is a lack of understanding with respect to how different forms of hearing protection affect the sounds you are hearing. We’re going to discuss what sound levels are dangerous, what sound levels are safe, and some ways to ensure that you aren’t doing damage to your hearing on a regular basis!
How Loud is Too Loud?
For starters, ask yourself how loud is too loud? Do you know? Most commonly you will see sounds measured in Decibels (dB). If you look at the box your ear plugs or muffs came in, you will see something like “18dB NRR” on the box. What does that mean, though? NRR stands for Noise Reduction Rating and what its saying in this example is that those ear muffs will reduce noise levels by 18dB from the level you are being exposed to. Here’s the real question you need to be concerned with, is that 18dB NRR enough? How loud is the gunfire you are being exposed to? For informational purposes, your typical conversation is about 60dB of sound pressure. Gunfire is up around 140dB to 160dB+!
Anything at or above 85dB of sound pressure is high enough to begin causing permanent hearing damage. One thing that comes into play with sound and exposure to sound is time. 85dB can cause hearing loss, but this occurs after approximately 8hrs of exposure. So if you heard noise that reached the 85dB level but it only lasted 5 seconds, you are unlikely to incur hearing damage on the spot. Here’s the catch, and this is the part you need to pay attention to: damage to your hearing is cumulative! So while 10 minutes of loud music is unlikely to cause hearing loss on the spot, it can be dangerous.
Music can often reach decibel levels of 100dB. For every 3dB in pressure you go up over 85dB the exposure time is cut in half! Obviously, this is different for everyone, and I’m not a Doctor, but I did stay at a Holiday Inn with wifi…so I did some reading. If you listen to that 100dB music for 15 minutes and you do even a little bit of damage, it’s permanent, and it’s cumulative. So if you routinely listen to loud music for a half hour to and from work you are doing some damage, and over time, it will get worse. It isn’t age that kills your hearing, it’s time and exposure to loud noise!
Hearing Loss From Gunfire
A lot of gunfire falls into the 150-160dB range for noise. That’s enough to cause hearing damage immediately without hearing protection. I know, I know, people go hunting without hearing protection all the time. Police and Military get into gunfights without hearing protection too, right? None of those people wind up running home unable to hear. So what’s the harm? This is where it’s kinda fuzzy and it’s different for everybody. Depending on the sound pressure and the levels of noise you are exposed to, the damage done can vary. It may take many many repeated exposures before you have measurable loss. Please remember though, ANY damage is cumulative. So once it’s done, it’s building up, and there’s no going back, what’s gone is gone.
There’s also something called a temporary threshold shift that occurs from short or long term auditory fatigue. Gunfire is a good example that can cause this and I’ve got an anecdotal story to go along with it. I work in Law Enforcement, and I’ve been through additional training that my department requires prior to carrying an AR15. We qualify with the rifles every quarter just like we do with our sidearms. There are always breaks during the qualification course of fire to allow people to top off magazines and what not if they happen to be running low. During a break I had pulled one of my ear muffs up off my ear so I could hear one of the guys I was talking to. Well, my dumb ass never pulled it back down. I didn’t realize my mistake until a dozen rifles started firing inside an enclosed Firearms Facility.
I covered my ear with my hand, but I wound up dealing with that temporary threshold shift. My ear was ringing for hours, but it did go away during the night as I slept. I’ve experienced no noticeable loss of hearing in that ear, though I wouldn’t be shocked to find some damage on a hearing test. I’m telling that story because it’s the hunting argument all over again. If the ringing went away and I don’t notice any issue, no harm – no foul, right? Does anybody think I should do that again at my next rifle qualification? Well the same applies to hunting, you need hearing protection!
Suppressed Rifle Fire
Here’s another issue I see, guys screw a can onto the end of their rifle and figure they’re good to go. Not really the case. Unsuppressed 308 and 243 rifle fire meters at about 156dB per 3M’s excellent data on the subject. Thunderbeast Arms Corporation makes some of the best suppressors on the market. Their new Ultra 9 suppressor brings 308 rifle fire down to about 132dB as reported by TBAC. That’s still well above 85dB. OSHA regulations say you should be exposed to less than a half hour of noise per day at 115dB to avoid chances of damaged hearing. A 20dB change in noise level will appear about four times louder. So even rifle fire mitigated by an excellent suppressor is still around 4 times louder than the max OSHA permits for a total of less than 30 mins per day in the work place. Starting to see my point? This is still America, and you’re free to do as you please, but just because you don’t notice a problem at the range doesn’t mean there isn’t one. There’s an expression when talking about hearing loss, “If your ears have adjusted to the noise level, the adjustment is likely damage to your hearing.”
I recommend doubling up on ear protection when shooting. Particularly unsuppressed rifles or rifles equipped with muzzle brakes. That’s some loud stuff, protect your ears. Doubling up on ear protection will give you better protection than one method alone. I like using the Surefire plugs under a set of electronic ear muffs like Howard Leight Impact Sports. This gives you pretty good sound reduction and protection for your hearing but the electronics will help amplify safe sound levels like voices so that you can still hear what people around you are saying. Understand though, that by doubling up your hearing protection, you don’t get the sum of the two NRR levels. If the muffs give you 20dB NRR and the plugs give you 25dB NRR you aren’t getting 45dB NRR. It’s probably more like 30-35dB. Still better than either, alone, but it’s not as awesome as a lot of people think.
You only get one set of ears, and trust me, you want to protect them. Hearing loss is no fun, and tinnitus will drive you insane. I was actually called to one guys apartment who was convinced the lady above him was sending sound waves through the floor to bother him. He had built a plywood coffin in his living room to sleep in because he thought it would block the sound waves. He had tinnitus. Protect your ears! If you have a big bore, or a rifle with a brake, consider doubling up with plugs and muffs. Even if you’re running suppressed, at least throw some plugs in. If you run your ears bare, it may not bother you now, but give it several years and you may regret your decision!