OK. I wrote this a couple of years ago. The above was an attempt at a quick fix that did not go well, so decided I needed to do better. Hope the links still work.
As it happens I know a little about this subject & it has come up in the past so I have taken the time to explain in some detail. I hope my comments are of assistance. I apologize for it being long winded but it is difficult to reduce it much further & still include al the info. Many people ignore hearing protection and regret it during their retirement. (particularly young men) Ignoring it will effect the quality of life during your later years.
NOISE FACTS
According to the current Australian OHS/WHS regulations exposing employees to noise levels over a peak of 140db or to noise at or above an average of 85dB(A)leq for the period of an 8hr shift.
It is the “peak” of 140db that applies to shooters. Just one exposure to 140db will damage your hearing to some degree.
Some examples for shooters of noise levels are: (I did not take these measurements but the source is fairly reliable)
22Lr 140 dB peak
12g 165 dB peak
3006 170 dB peak
So every time you fire a rifle (without hearing protection) you are doing a little damage to your hearing and the damage compounds throughout your life. The loss of hearing will not become noticeable until later in life and by then it will be too late. So hearing protection is about being able to hear later in life.
And when measuring noise you must remember that an increase of 3dB is double the sound power. So an increase of just 2 dB is very significant. Immediate irreversible damage is likely to occur at 140dB.
HEARING PROTECTION
In Australia hearing protection is sold in 5 classes that are laid down in Australian Standard 1270. Class 1 being the lowest level of protection class 5 the best. Below is the minimum reduction (the technical term is attenuation) in dB required of each class of hearing protection, Muff or plug at the ear.
1. = 10 - 13dB
2. = 14 - 17dB
3. = 18 – 21dB
4. = 22 - 25dB
5. = 26dB or greater
Muffs & ear plugs perform differently at various frequencies further complicating which muffs to purchase. The above is essentially an average at various frequencies. Some muffs perform best at low or high frequencies.
So if the noise level of a 3006 is 170dB you can expect a class 5 muff to reduce the exposure to the ear down to at least 144dB, (170-26=144) but perhaps not all frequencies. So the wearing of anything less than a Class 5 would be fairly useless to shooters. Even the class 5 may not completely prevent hearing loss. However it will certainly go a long way in reducing hearing loss. Continued and regular exposure to gun fire of say 130db will still damage hearing over time.
Many retailers such as Bunnings sell ear muffs but you get what you pay for and often it is not clear what “class” they are on the packaging. As mentioned above, this is important. In addition cheaper muffs generally wear out very quickly, significantly reducing the level of protection provided and the wearer is usually unaware that they now have reduced hearing protection. So you start off with say a class 3 and a yr later it is a class 1 muff for example.
WHAT SHOULD I BUY?
Ear muffs, both standard and electronic provide the best protection and I would recommend class 5 for shooting. The down side of standard ear muffs is the effect they will have on communication and possibly not being able to hear other hazards nearby, e.g a truck heading in your direction.
Ear plugs, I cannot recommend the use of off the shelf ear plugs I rarely see them worn correctly. However if worn correctly and they fine, very effective and convenient to wear in the field. Personally fitted plugs should be a better option for most users if you prefer plugs check what the expected attenuation will be before purchasing.
As mentioned earlier electronic muffs are great and fitted with a microphone and amplifiers that automatically switches off at 85dB. This allows you to hear normal sounds and your ears are protected from loud sounds. However quality ones are expensive & you get what you pay for.
If you are shopping around for a pair of muffs I suggest you visit a safety specialist retailer such as protector alsafe or safety equip. In my experience the staff generally know about the products they sell and will steer you in the right direction. And they also sell muffs of the less expensive brands. Stick to well known brands is always good advice.
Another trick is to wear plugs under miffs increasing the level of protection.
Avoid overseas purchases on ebay etc as you may not get the level of protection you need.
ARE ALL RATINGS EQUAL.
In an answer NO.
If you had 3 sets of muffs and all were rated 33 dB attenuation then you would rate them likes this. 1 = best 3 = worst
1. SCL 80 (the Australian/NZ system)
2. NRR
3. SNR
So the muffs for $110 are SNR 33 dB are equal to about 26 dB they are a low end Class 5. Still good value but for serious target shooters probably not good enough. By wearing a pair of ear plugs under the muffs you will increase the protection by about 5 to 7 dB if worn correctly which few people do. Also generally speaking, due to the nature/physics of sound the higher the class/attenuation the bulkier they are the better. The reason they are not the same is the testing and measurement requirements vary. Hope this helps .
EDUCATION
Here is a couple of links for two very good videos. If links do not work copy & past the line below into your browser address bar.
Here is a link to a good general video about sound and hearing protection that all shooters should watch, about 17 minutes. The hearing video
https://youtu.be/mbwElB6uVuUHere is a link to a 70 second video showing how to fit ear plugs correctly
Fitting video
https://www.youtube.com/watch?v=ghNFKsxJuvYI hope this helps people to better understand the importance of looking after their hearing and how to do just that.