Way back in the early days of our business, and many times since, we have heard the plea, “I just want to hear nothing!”
Some refer to this concept as artificial deafness -- that is, the notion of achieving a complete and total lack of hearing any sound whatsoever. Unfortunately, artificial deafness is simply not possible. Why not? And more importantly, how can we eliminate all those irritating noises if actually hearing absolutely nothing is not an option? Since this is such a great question, I thought I would share with you a short essay on the subject.
First the basics: Sound, in the form of vibrations, enters the inner ear, where the vibrations are turned into chemical energy via specialized nerves and thereby transmitted to the brain, where the chemical nervous energy is interpreted as sound. These vibrations arrive at the inner ear via three general pathways; primarily through the ear canal, secondarily through bone conduction through the bones of the head, and thirdly, through soft tissues from the torso up through the neck. Ear plugs can only block the primary pathway, that is, the ear canal, leaving about 5% hearing via the other two pathways. An ear plug rated at 33 NRR (the highest NRR rating available for a single ear protector) effectively blocks all sound from entering via the ear canal.
Ear muffs, because they cover a portion of the bones in the head, affect both the primary pathway and the secondary pathways of sound. Ear muffs, though, are not as good at blocking sound as are ear plugs for a variety of reasons. However, because the ear muffs do block some sound from traveling through the bones in the head, the combination of ear plugs and ear muffs offers a profound level of noise isolation that is about as close to artificial deafness as you are going to get in the real world. The effect of a combination of ear plugs and ear muffs, called dual protection, can be estimated by adding 6 dB to the NRR of the highest rated of the two. For example, if you use an NRR 33 ear plug with an NRR 20-NRR 30 ear muff, you will get a total effective rating of approximately NRR 39 (33 + 6). To put that in perspective, with the NRR 33 ear plugs alone, you would avoid about 95% of what you would hear with the open ear. Add the 6 dB, and that would further reduce the sound you could hear by about 40%, bringing you to about a 97% noise avoidance level. I know that does not sound like much, but give it a try, and I am sure you will be impressed with the result.
I want to emphasize a couple of points:
First, most ear plug users do not realize the full rated NRR of ear plugs, because very few people take the time to properly insert their ear plugs. This is especially true of roll down foam ear plugs. This video demonstrates the proper way to fit a foam ear plug. I would encourage anyone who has not done so to take a few minutes to review this information, because the results of simply fitting the foam ear plugs solves almost every situation in which people tell me their ear plugs do not block enough noise. Not all certainly, but many people are dissatisfied with their ear plugs simply because they do not get them inserted deeply enough to benefit from their full rated performance. The noise blocking power of a simple, inexpensive foam ear plug, when properly inserted, is quite impressive.
Second, ear plugs become more expensive, not as the NRR goes up, but as the ear plug offers other capabilities. Reusable ear plugs, for example, do not offer as high an NRR as do foam ear plugs, but they are more expensive because they are more durable and/or they are easier to insert. Custom molded ear plugs seldom offer as high an NRR as do foam ear plugs, but they cost many times what a foam or reusable ear plug costs -- because custom plugs are far more durable, and they are more comfortable because they fit perfectly. Natural sound musician’s ear plugs are much more expensive than foam ear plugs despite the fact they offer a lower NRR. The benefit of musician’s ear plugs is that they offer a frequency response that is similar to the open ear, allowing those who need to hear, but at a reduced level, to achieve a much more natural sound experience. The point is, not all ear plugs are designed to simply eliminate noise. Some just take the noisy edge off the world without distorting sound. Others help manage the pressure changes and the cabin noise during airplane flights, or help the motorcycle rider reduce the damaging effects of wind noise while letting her retain full situational awareness in traffic.
So What To Do?
Back to those who want artificial deafness. If you have tried step one, that is choose an NRR 33 ear plug and get it properly fitted, then go to step two: add an ear muff over the properly fitted ear plug.
(By the way, if you have tried a foam ear plug and hated it because it hurt or was too big or too small to fit you properly, do not give up just yet. We offer inexpensive trial packs which are collections of many different ear plugs that let you try a bunch of different ear plugs to find the one you like best.)
Ear muffs are easier because it really does not matter much what NRR rated ear muff you choose. (Our ear muff chooser lets you see the features and pricing of many different models.) The primary benefit of adding ear muffs over ear plugs (dual protection) is that the foam seal around the ear cups adds the 6 dB of additional noise reduction by reducing the surface area of bones in the head available to conduct sound (through the secondary pathway). The ear plugs block the ear canal and the foam seal against the head around the ear, reduces the sound traveling through the bones in the head.
If these suggestions have enabled you to solve your noise problem, congratulations! Glad I could help. If you are still not satisfied, read on. I have some additional strategies you may want to consider.
Some people find when they use highly effective ear plugs that they get anything but quiet as a result. Instead of hearing the noises of the world that were a bother, they hear their own internal noises: breathing, heart beating, swallowing, hands or hair touching their ears or ear plugs, or random tinnitus noises. In fact, the quieter you make your space in the world, whether by adding ear plugs or by retreating into a heavily insulated space, the more you become aware of all the noise generated by your own body and mind. Because of this, eliminating the distractions of noise can be quite a challenge, but it is simple to accomplish once you understand the systems you are working with just a little better.
Some years ago I developed a conceptual system called the Total Isolation System (TIS). Although we do sell a product called the Office Isolator which embodies the principles of TIS, it is more a concept that you can effect using many different components you can readily acquire or may already have. A TIS system requires two components: a masking sound source and a set of isolation earphones.
There are two parts to TIS.
Part one: Your hearing is highly variable, depending on many factors, but mostly depending on the level of sound present at the ear drum. The more sound hitting the ear drum, the less sensitive the brain becomes to the sound, up to a point. Importantly, the first bit of sound has the greatest effect. Just a little sound added to a quiet environment significantly reduces the acuity of your hearing. Adding more sound has a much lesser effect on hearing acuity. Conversely, the quieter the environment, the more acutely aware of sound the mind becomes. Take the illustration of a dripping faucet in a quiet house deep in the night. You can hear the dripping from 50 feet away, making you crazy. In the daytime, when ambient noise is higher due to increased traffic, radios or TVs going, people talking, dishes clattering, the keys on the computer clicking, and a myriad of other sources, you can be standing directly over that same faucet and you cannot hear the drip no matter how hard you try. Why? Because your mind has turned down its sensitivity level to help protect you from all that noise it is hearing. For those who suffer from tinnitus, the same process is what makes tinnitus worse at night and less of an irritant during the day. Being able to hear some sound can be a good thing… But not if the sounds you hear aggravate you and/or cause you to lose your concentration.
Your mind uses active processes to decide what, of all that you are hearing, to bring to your attention. Sudden noises grab your attention. The sound of conversation causes your mind to go into overdrive to try and interpret the words it is hearing, making human speech the most intrusive sound out there. By contrast, sounds that carry little or no information are quickly ignored. Think of the buzzing of the light fixtures in your office when you first arrive in the morning. You can readily hear that sound. Later in the day, though, you are completely unaware of that sound unless you intentionally focus on it. Try that and you will see what I mean. This ability of the mind to ignore low information sounds is the key to the effectiveness of TIS.
TIS works by injecting into the ear a sound that carries no information: a masking sound that is automatically ignored by the mind. The presence of the masking sound, even though it is not being "heard" after a few minutes, still causes the mind to be less sensitive to all the other sounds you were hearing. A masking sound you put into your ears not only acts to reduce the acuity of your hearing, it also works to mask the irritating sounds in your environment by interfering with your ability to clearly hear them. So the masking sound does two things: it causes your hearing to be less acute so you do not hear the irritating sound as vividly, and it interferes with your ability to hear the sound by drowning it out.
Part two: If all you do is try and drown out the irritating noises in your environment using a low information masking sound like white noise, you will encounter the problem often referred to as the signal to noise ratio. In order to drown out the sound of a nearby conversation, or traffic outside your bedroom (a.k.a. the signal), the masking noise would have to be louder than the signal. Such a loud noise would be irritating to you as well as to everyone around you. To address this problem, TIS first reduces the signal by using an isolation earphone or headphone. Isolation earphones are in-ear headsets that use very small speakers (called drivers or receivers) inside the ear canal to deliver sound from a device such as a white noise machine, iPod, smart phone or CD player. The earpiece tips on isolation earphones are made of a noise isolating material such as foam or molded silicone with multiple flanges. The drivers project sound through a central opening in the ear tips. You get a great reduction in the ambient noise you are trying to avoid by means of the blocking effects of the tips; that is, the noise blocking tips reduce the level of the signal you need to mask. Some of the irritating noise will still enter your ears despite the noise blocking feature of the tips, but at a much reduced volume. With the isolation earphones in place then, you can set the volume of your masking sound as needed to completely eliminate your ability to hear the rest of the irritating noise you are trying to avoid. The result is total isolation.
CAUTION! TIS can work so well that it can be dangerous. The most common danger is that you will turn up the masking sound to a dangerous level. This is easier to do that you might think, because hearing damage can occur even when the sound level does not hurt, and because hearing damage is a cumulative event. Sounds that cause no damage when the exposure is of short duration can cause damage if they persist over a long enough time. The second danger is loss of situational awareness. With TIS in operation, you can hear nothing... including the fire alarm, the screeching of tires as a lunatic rounds the corner on your side of the street, the careless worker carrying a ladder behind you, etc. We are often unaware of the profound uses we make of sounds in our environment to avoid calamity, and without which we are quite vulnerable.
If you choose to use a TIS approach to managing the irritating noises in your environment, be careful.
- Do not use any more masking sound than you absolutely need.
- Do not use the system any more time than you actually need it, so that your ears get some rest between uses.
- Do not use the system when you are in a dangerous environment, such as driving a car, walking in a busy city, or working in an industrial environment.
- Maintain your situational awareness for the safety of yourself and others around you.
So, there you go. You have a very long answer to a short, but profound question: How do I eliminate the irritating noises around me?
- Try hard to make disposable foam ear plugs work for you. They are the least expensive option, and they can solve all but the most severe irritating noise problems.
- If ear plugs alone will not solve the problem, add a pair of passive ear muffs over the ear plugs, and see if the additional 6 dB is adequate to solve your irritating noise problem.
- If dual protection systems do not work, try a Total Isolation System (TIS) -- but be careful with this approach. The general rule is that if the tool is sharp enough to do the work, it is also dangerous enough to do you harm if used without adequate care.
TIS is a very sharp tool, so use it with caution -- and enjoy the Total Isolation from all the irritating noises around you.
Be well, and do the right thing,
--Tom Bergman, Marketing Director
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