Hearing Protection Study

[86er]

Without getting into all the particulars, I have been doing a study on various types of hearing protection. Until it is finalized and published I am not going to reveal every detail, but some of the more enlightening findings are important enough to share now. Leverguns firing centerfire cartridges are loud. In most cases the gun is shorter from the shooter to the muzzle, the bore is medium or larger and the velocity is moderate. It is not the higher crack of the high velocity cartridges, but still loud. A lot of shooters use earplugs and some use head-sets. More often these days the shooters that use hearing protection opt to use a combination of ear plugs and a head-set. This information is specifically related to the head-sets. The NRR is the noise reduction rating and is a occupational standard used to compare products. Head-sets range from 19-36 NRR, meaning in short they block 19-36 decibels of sound. Generically, 85 and below is thought to have a minimal affect on hearing. Some levergun cartridges will generate 116 db, as an average. Therefore, you'd need a NRR of 31 just to get in the "safe" zone. Here's the important findings: Many head-sets are not blocking the NRR they are stated to. This is due to a phenomenon known as bone conduction. Sound through waves and vibration travel through solids at different rates, depending on the make-up of the solid. People with single-sided deafness are often fitted with a cup that is screwed into the bone behind the deaf ear. An amplifier is attached to the cup. The sound is transmitted through the bone and picked up by the other inner ear and allows hearing from both sides. This is another involved topic but for now that'll do. So, the strap, or band on the head-set is a major contributor to its effectiveness. A headset with a solid plastic top piece will conduct as much as 20% of the "sound" into your skull, allowing your silia to pick up much more db than you thought The Howard Leight QM headset is a good example of a wide, solid strap that hugs the head tightly. A remedy that reduces the conduction is to have ample padding between the strap and the head. A better system is the wire band. This is usually two wires encapsulated in a plastic sheath. The Peltor Optime is one such product with this design. The thin wires in the top strap do not conduct the sound to a measurable amount nor do they press against your head very tightly. Another good design is the single wire behind-the-head type. Ironically, the behind-the-head types often have a lower NRR because it is impossible to get the ear cups as tight as other designs on the microphones that measure the NRR for the rating. However, the bone conduction is almost none with this type so the actual amount of sound reaching the silia is less than a type that conducts a lot. So a headset with a solid top strap with a NRR of 29 is actual performing more like a 23 NRR. That's a 15% difference. This can be the difference between hearing damage or not. If a cartridge makes 109 db, a 29 will put it well below the 85 db (safe zone) at 80 db but if it is actually only 23 it will be 86db and on the verge of causing slight hearing damage. Most differences with a hard solid top strap and a tight fit are closer to 20% so the difference is quite a bit more. Of note, in some case the ear plugs used in conjunction with a head-set that allows bone conduction are virtually nullified. In other words, the amount of NRR the ear plug is blocking is then allowed to enter the ear to affect the silia via conduction, and it's as if you didn't use the plugs at all. Of course without them in combination the affect would be worse but just for comparison you would be better off using a low - conduction head-set without ear plugs than using a high -conduction head-set with ear plugs.
So, in conclusion I must say that any hearing protection is better than nothing but the most protection is afforded by a combination of ear plugs and a low-conduction head set. If the cartridge generates 109 db and the ear plugs reduce 21db plus the head-set blocks 26 db you have 62db. 62db is not known to cause immediate hearing damage and the long term effects are extremely low. Think smart when you purchase your hearing protection.

[Old Savage]

Thanks for the info. I would have thought it was the air wave pressure that causes the damage. Wonder what studies have been done on damage by bone conduction.

[pokey]

thanks

[AJMD429]

That's just one MORE reason our gun laws SUCK...there is NO sensible reason that 'suppressors' should be restricted, taxed, regulated, or whatever euphemism they use for 'infringed'...!

Yeah, I know most folks wouldn't want a big black tube stuck on the end of their walnut-and-blued vintage levergun, because it would 'look silly', but for most guns, a decent built-in suppressor could be very compact, protect the crown better than silly "11-degree recessing", and add some serious decibel reduction - it's only when you want nearly-silent shooting that the suppressors start getting huge.

Whenever the government starts a 'program', such as the "war on alcohol" a century ago, it just can't seem to shut it down, even if the public votes to do so; the ATF basically sprang from the 'need' to keep handing money to all the hirelings they had out busting up stills and raiding parties to arrest anyone partaking of the evil brew. God forbid they lay any 'government worker' off and make them go back to the private sector and/or do something constructive or productive.

The novel "Unintended Consequences" by John Ross does a good job of illustrating the cascade of bad things resulting from the 1934 National Firearms Act, but I don't think they addressed all the hearing damage as our guns became louder not only due to advances in technology, but legislative idiocy...

Anyway, stepping off the soapbox (...sorry I got 'political'... ) - looking forward to 86er's report - I think most of us are far too lax regarding hearing protection. We think of it after we start losing hearing, much like we start watching our diet after we're diabetic and have had bypass surgery.

Those levergunners near Indianapolis might want to go to the (INdiana Gun Owners link --> ) HUSH Indiana event June 12th; I don't own a suppressor (yet), but it "sounds" like a fun event... The HUSH club website also have info about the event - http://www.hushindiana.com/News.html

[El Chivo]

Well I double up all the time, I usually shoot .22lr but somebody always shows up with a 50 caliber elephant gun to show off his manhood. I even use plugs in the field with my airgun.

[RIHMFIRE]

great information....

I typically only wear ear plugs....whether I am shooting skeet, trap, sporting clays
or my leverguns...The headset are just too cumbersome when shooting clays...


I just shove the ear plugs in, just far enough so they touch....
a few have fell in...

[Jeff H]

.........there is NO sensible reason that 'suppressors' should be restricted, taxed, regulated, or whatever euphemism they use for 'infringed'...! ...........

If it's good for gun owners, it won't be done. The noise is a "good" reason to PREVENT people from shooting.

Thanks, 86er. I alternate between 'muffs or 'plugs myself.

Rifle or shotgun - 'plugs. Muffs clunk against the stock and that's a noise that I find rather obnoxious in itself.

Handgun - 'muffs. 'Plugs are a PITA to install/remove (YES, I am putting them in my EARS!) to converse with a fellow shooter between shooting/checking targets.

Chainsaw - 'plugs. The starp on the top hurts my head after a while (soft spot?) and you can't snug a hat up around your ears with them and I usually have them in for a while.

Lawnmowing/running tractors - 'plugs for the same reasons as using the chainsaw.

Working in the wood shop - 'muffs. They are on and off several times because I hate having them on and only do when I have a machine running. I also hate noise and dust, so I use the machines as little as possible. Besides, getting powder residue or sawdust on your plugs sucks. Looks like you don't clean your ears.

I hate using hearing protection but hate not being able to hear even more.
Need to pretect what I have left.

[earlmck]

Looking forward to your full report, 86er. This is important stuff to us old guys who can't afford to loose any more hearing.

I double-bag when shooting a lot, and especially when I use the big pistols, or short-barreled rifles. But my real favorite, that I use most of the time, is my hardhat that I wear on a daily basis running a chainsaw in the woods. The muffs snap away from the ears when you want to hear, snap back down for protection, and are comfortable enough to put in an 8-hour day wearing them. I hadn't thought of the bone transmission part that 86er brings up, but I'd bet the old hardhat scores real well on that aspect.

Here's a pic of my old hat: yeah, there are some customizations front and back for sun/rain/snow/tree-needle protection (patent applied for) but the main thing for our purposes is the neat muffs. Oh yes, you have to go on-line to find muffs with a good db rating: Peltors or Husquvarnas from the local hardware store or saw shop seem to top out at 23db, which is a little light even for chainsaw use, let alone for shooting protection.

[crs]

86er,
No answers, but a question for you;
Will your final report also cover the custom fitted, adjustable shooters ear protection often seen at the shotgun ranges? Are these types also suitable for field hunting with shotgun and rifle or pistol?

[JHarold]

Interesting report.

My own situation is at 73 I already have hearing loss, and wear hearing aids.
I usually take them out, then wear electronic muffs. The muffs will help me pick up conversation around me. otherwise I can't hear range commands. I am going in next week to be fitted for my third set of hearing aids. It seems crazy to wear hearing aids and then wear muffs over them.
You young guys take heed, take care of your hearing, It ain't macho to wear hearing aids instead of hearing protection when you are young and invinsible.

[bj94]

I did a lot of shotgun shooting in my youth with no protection. I was using an autoloader with 30" barrel, and this is the quietest combo with respect to the shooters ears. On occasions that I've shot someone else's gun with a short receiver and shorter barrels, it is a LOT louder.

All of my centerfire rifle and handgun shooting has been with muffs. More recently when being around rifle shooters I've worn custom fitted ear plugs in addition to muffs.

I don't think muffs are sufficient for loud gunshots because we also always wear protective glasses at the same time and the muffs can't seal properly around the earpieces of the glasses.

[86er]

The custom fit plugs that are "injected" into each ear and then harden are one of the best for NRR. The one's I've tested were made by various companies for various people. If they are done properly they get an NRR of 36. That is one of the highest ratings on the plugs. The reason is that it blocks more of the space that would allow sound in, as they fill the opening on the outside of your ear on one end and taper right into the ear canal on the other. As far as field use - that's up to you. I find that they are comfortable enough for a few hours use and I can hear sufficient in the field for bird hunting or duck hunting. If I need to hear something specific I pluck one out for a moment. For rifle hunting it is hard to hear game walking or hear a bullet strike - but depending on what and where I've used them for that type of hunting too. Most of the time for rifle hunting I am using a fairly expensive electronic plug set that turns off at the shot. Since rifle hunting is limited in the # of shots these work adequately for those occassions.

[piller]

I always use the soft foam plugs which are rated at 31 to 33 db, depending on brand. I usually use muffs in addition. I wear a ballcap and the head strap fits over it. The muffs I use are the electronic type rated at 23db. Having had tinnitis all of my life, I am not sure what silence is, and I have had hearing loss since before I ever fired a gun.

[Bullard4075]

Thank you 86 , a very timely report. This subject has been in my forefront recent days.
At work I am to advise customers of the proper hearing protection. Internet study yielded
much of the same information but in a much less understandable jumble. You made it easy
to understand.

Could one place a foam "cushion" between a hard headstrap and the head to prevent
sound transmission?

[86er]

Bullard - the short answer is yes. The more cushioning between the hard strap and your head, the less conduction.

[stickfred]

Thanks for your research and post 86er. Though I'm still waiting for a rifle, this is good information for a newb like me. The transmission of sounds you describe make sense to me with my limited understanding of harmonic vibration (akin to holding down a piano key without striking the string and then using your voice to activate the string when your voice hits the same note).

After reading yours and all the other posts, I went about looking for for the best hearing protection. One sight insisted on combining hearing and sight protection mixed together. While looking at the pages and with your original post fresh in my mind, another thought came to me and I would like to offer it to you for consideration. The "arms" of glasses are of a solid material and rest against bone just above the ear. Could this be another source of sound penetration through bone conduction? Just a thought that it may be something to consider in your studies.

Thanks again for your energies and sharing your information....I appreciate it very much. All the best to you.

[KirkD]

Very informative thread. Thanks for posting it 86er!

[Roland]

Thanks for the info. I would have thought it was the air wave pressure that causes the damage. Wonder what studies have been done on damage by bone conduction.

I was going to say I've heard that the headphone style hearing pros are much better because plugs don't protect against the noise transferred via the bone. I never go shooting without my Sordin Supreme Pro-Xs and if need be I double up with plugs.

I have really good hearing and even suppressed .22lr is kinda loud to me.

[Ysabel Kid]

That's just one MORE reason our gun laws SUCK...there is NO sensible reason that 'suppressors' should be restricted, taxed, regulated, or whatever euphemism they use for 'infringed'...!

+1

I have hearing loss and I know it is getting worse. In my youth I never wore hearing protection while firing thousands and thousands of .22's and shotgun shells. Didn't start wearing hearing protection until I was in my teens shooting centerfire handguns. By then it was too late. If I get anywhere where there is a lot of background noise, I cannot follow a conversation below "screaming" level.

I use just ear muffs when shooting (cutting the lawn, using any power tool, etc.). Unfortunately, I have busted both ear drums in the past, which hasn't helped my hearing. What it apparently has done is make my ears very sensitive to having anything stuck in the ear canal. More often than not, I usually come down with some kind of ear infection shortly after having worn ear plugs. So, I don't put anything into my ear canal (including ear buds for electronics).

Paying the price for youthful idiocy...