By Wu Chin
I have seen shooters sporting various hearing protection at our shoots and have been asked more than a few times why their ears still hurt. I have also given out ear plugs to supplement their inadequate earmuffs. Then there are those who slip off one ear muff to listen to someone while shooting is going on. I clipped and pasted this guide to provide a resource to start your understanding of ear protection and what is available. The sources are noted for your research.
Besides the NRR rating there are other concerns when picking up a pair of earmuffs. The ear protection has to fit your hearing needs and your physical needs. If you have normal hearing any passive or electronic earmuff might be sufficient given the activity and NRR rating you need. If you have deficient hearing in one ear, you might need an electronic muff with individual controls if you want to hear conversations and range commands without staining. If you wear glasses and want to use earmuffs, you need to make sure the ear cushions are soft enough to cover over your glasses and the safety glasses ear paddles. If you will be using these in hot weather, the nylon or plastic ear cushions may cause sweating while the softer leather cushions breathes better.
Do you have a smallish head? Regular muffs may not fit well. Maybe a youth earmuff is appropriate. The cushions must enclose your ears and seal tight. If the muffs are too heavy or too tight you won’t be comfortable and, after prolong period, might end up with a headache. We usually shoot two hours at our monthly events but with special shoots may be four to five hours. There is also a difference in indoor range use vs outdoors. The indoor range is a sound box which will capture the sound and sustain it. Sound dissipates quickly in the outdoors so the NRR requirements may not be as high. Does this sound like buying holsters? Yep.
Noise levels are measured in decibels, which we write "dB". A gun shot is rated at 149dB and to compare, the typical office generally has a noise level of 60dB to 65dB. Noises louder than 80 decibels are dangerous and can cause immediate and permanent hearing loss. When we look at what hearing protection to buy, we need to pay close attention to the product's NRR, or Noise Reduction Rating, which is defined as the maximum number of decibels (dB) that the hearing protector will reduce the sound level when worn. By law, all hearing protection products have to have a NRR rating. The highest NRR rating you can get is 33 NRR. A product with a 28 to 31 NRR is recommended for indoor shooting. There are two different kinds of hearing protection, ear plugs and ear muffs. The National Institute for Occupational Safety and Health actually recommends using both earplugs and earmuffs together when shooting. It might come as a surprise to hear that earplugs can actually offer more protection than ear muffs, because ear plugs fully block the ear canal.
There are quite a few different types of ear plugs: single use, multiple-use, banded and corded. Banded or corded ear plugs are best if you move between a noisy place and a non-noisy place, like between the shooting range and your range's lobby. Multiple-use earplugs are easier to use because they do not require rolling to fit in your ear.
Earmuffs are either electronic or passive. Electronic earmuffs amplify quieter sounds, allowing you to hear your range master's commands. These earmuffs will have integrated microphones and some have independent volume controls. Passive earmuffs simply block sound using foam and other materials located inside the ear cup. One thing to look for in your earmuffs is the style of band. Plastic headbands hold their shape better than a metal band. Metal bands can become stretched through time, leading them to decrease the level of protection. Other earmuffs offer added features such as a built-in AM/FM radio or has a jack to plug in your iPod.
Noise Reduction Rating (NRR) is the measurement, in decibels, of how well a hearing protector reduces noise as specified by the Environmental Protection Agency. The higher the NRR number the greater the noise reduction. While wearing hearing protection your exposure to noise is equal to the total noise level minus the NRR of the hearing protectors in use. For example, if you were exposed to 80db of noise but were wearing earplugs with an NRR of 29, your actual noise exposure would only be 51dB.
When dual protectors are used, the combined NRR provides approximately 5 - 10 decibels more than the higher rated of the two devices. For example using disposable ear plugs (NRR 29dB) with ear muffs (NRR 27dB) would provide a Noise Reduction Rating of approximately 39 decibels.
The amount of on-the-job noise exposure can be determined through various testing devices. Excessive noise is defined as 85-90 decibels or more over an 8 hour period.
Examples of noise levels considered dangerous by experts are a lawnmower, a rock concert, firearms, firecrackers, headset listening systems, motorcycles, tractors, power tools and industrial machinery. All can deliver sounds in excess of 90 decibels and some up to 140 decibels.
150 dB = Rock Concerts at Peak
140 dB = Firearms, Air-Raid Siren, Jet Engine
130 dB = Jackhammer
120 dB = Jet Plane Take-off, Amplified Music at 4-6 ft., Car Stereo, Band Practice
110 dB = Machinery, Model Airplanes
100 dB = Snowmobile, Chain saw, Pneumatic Drill
90 dB = Lawnmower, Shop Tools, Truck Traffic, Subway
80 dB = Alarm Clock, Busy Street
70 dB = Vacuum Cleaner
60 dB = Conversation, Dishwasher
50 dB = Moderate Rainfall
40 dB = Quiet room
30 dB = Whisper, Quiet Library
The performance of earplugs and earmuffs varies between brands and styles. One way to choose a hearing protector is to compare Noise Reduction Ratings. The Noise Reduction Rating, or NRR, measures the muff's or plug's ability to block out noise or "attenuate"; sound. This measurement is stated in decibels; a plug with an NRR of 26 blocks out a maximum of 26 decibels of noise. The NRR listed is the maximum protection that could be achieved if the plug fit the wearer perfectly and was inserted correctly. In most work situations attenuation is half of the listed NRR. For example, if the NRR is 30 the hearing protector most likely blocks out 15 decibels of noise.
Disposable Ear Plugs LINK
Safety Ear Muffs LINK
If you are not familiar with electronic shooter's ear muffs, here is a brief explanation of how they work. Fundamentally, the passive hearing protection provided by the ear muffs protects your hearing from loud noises such as are produced by gunfire or loud machinery. Inside the muffs are electronic components including microphones that pick up sound from outside the ear muffs, an amplifier that makes low volume sounds in the environment easier to hear with the muffs on than with the uncovered ear, and speakers that project the amplified sounds to your ear from the inside of the ear muffs.
The amplifier used in electronic earmuffs includes the "smart" capabilities of the ear muffs. In older (and many cheaper) models, the technology was a simple "stop gate" technology. These ear muffs would amplify low level sounds, and when the sound level picked up by the external microphones reached a dangerous level, the amplifier would simply turn off, leaving the user with the passive protection provided by the earmuffs. When the dangerous sound went away, the amplifier would resume amplifying the environmental sounds. The speed at which the amplifier could switch between off and on, is referred to as "attack time." The faster the attack time, the less the user is cut off from being able to hear what is going on around him.
More expensive and advanced models feature the latest amplifier technology, generally referred to as "sound compression." This technology lets you continue to hear all of the sounds in the environment, but compressed into a lower-volume stream of sound that is essentially continuous, without the on-off sound you get with stop gate technology. With sound compression you hear more than you can without the ear muffs, but all at a safe volume level. Older (and many cheaper) models contain just one or two microphones. With these ear muffs on, the user can hear low level sounds because they are amplified, but the small number of microphones makes it difficult to determine the direction from which the sound is coming. More expensive electronic ear muffs generally feature 2 microphones on the outside and two speakers inside each ear cup, which give the user an excellent sense of direction. Directional sensitivity is extremely important in hunting and military/police tactical situations, and a very nice feature in virtually all other applications.
In summary, the following features should be considered when buying any electronic hearing protection and amplification ear muffs: