What Is Limiting Ear Protection's Maximum Effectiveness? Noise Reduction Ratings (NRR)

[Dankmemes]

Why is the highest rated decibel rating for ear plugs around 30-35 decibels?

I was thinking about this recently and if someone were to create some kind of extreme protection like 60 or 70 decibel reduction ear plugs/ear muffs that would be a godsend to the tinnitus community.

It would allow even the most severe tinnitus sufferers to walk almost anywhere they ever wanted and have a much more fulfilling life.

We can finally stop living in fear of sound.

I know it would be uncomfortable but would it be possible to produce a custom made ear plug that is the exact shape of you ear and make it out of some heavy, soundproofing material like maybe some kind of metal?

It would be uncomfortable but much more effective.

Has this been tried yet or is there just too low of a need for someone to attempt to create one?

 

[Ed209]

There is a physical upper limit because sound will eventually make its way to the cochlear via bone conduction throughout your entire body. The only way to get around this would be by creating a suit of armour that essentially shields your entire body from all external noise. However, this is obviously highly impractical. With that said, it's quite rare that sound will be loud enough to be a bone conduction concern whilst wearing good earmuffs and/or earplugs. The bones of your skull are generally accepted to provide around 40 dB of reduction. I believe the tipping point starts somewhere around a sustained noise of around or above 115 dB plus, which is actually really hard to come by. It's much more of a rarity than it is the norm.

In which case, don't go into those environments in the first place. It's not like you can accidentally end up on the front row of a metal concert. Even then, it's rare they go above 115 dB, and the current trend shows they are coming down in volume rather than up. I'll note here that Corey Taylor said they limit Slipknot shows to 107 dB, and they are still known to be really loud.

As a side note to anyone scared of going to premier league matches in the U.K. Here's a list of the average recorded levels, over 90 minutes, in all the stadiums this year (peaks are often in the 90's after a goal is scored). As you will see, they are generally not as high as the exaggerated 'phone app' figures you often see on here - where I've seen cinemas apparently hitting 130 dB and all sorts of other crazy figures for other things. Remember folks, the decibel scale is logarithmic, so that would mean those cinemas would be throwing out well over 10,000 times more energy than the loudest premier league game!

https://www.expressandstar.com/spor...wolves-fans-loudest-in-premier-league-so-far/

 

[gav01]

I always assumed that if I read NNR Insert number here then that was how many decibels the earplugs would reduce the noise until now...

How does NRR change decibels of exposure?
When hearing protection is worn, your level of exposure to noise is based on the NRR rating of the protection device being used. Keep in mind, however, that while the NRR is measured in decibels, the hearing protector being used does not reduce the surrounding decibel level by the exact number of decibels associated with that protector's NRR. For example, if you are at a rock concert where the level of noise exposure is 100 dB and you are wearing earplugs with an NRR 33dB, your level of exposure would not be reduced to 67 dB. Instead, to determine the actual amount of decibel deduction applied (when decibels are measured dBA which is the most common), you take the NRR number (in dB), subtract seven, and then divide by two. Given the previous example, your noise reduction equation would look like the following: (33-7)/2 = 13. This means that if you are at a rock concert with a level of noise exposure at 100 dB and you are wearing a hearing protector with an NRR 33 dB, your new level of noise exposure is 87 dB. If you are wearing a product with an NRR of 27 it would deduct 10 decibels (27-7/2=10).

*To maximize noise reduction, hearing protectors must be worn properly.

How does wearing dual hearing protectors change NRR?
When hearing protectors are worn in combination (i.e. earplugs AND earmuffs), rather than adding the two NRR numbers together, you simply add five more decibels of protection to the device with the higher NRR. For example, using 3M™ E-A-R™ Classic Earplugs (NRR 29) with 3M™ Peltor™ H7 Deluxe Earmuffs (NRR 27) would provide a Noise Reduction Rating of approximately 34 decibels.

 

[MattS]

I always assumed that if I read NNR Insert number here then that was how many decibels the earplugs would reduce the noise until now...

How does NRR change decibels of exposure?
When hearing protection is worn, your level of exposure to noise is based on the NRR rating of the protection device being used. Keep in mind, however, that while the NRR is measured in decibels, the hearing protector being used does not reduce the surrounding decibel level by the exact number of decibels associated with that protector's NRR. For example, if you are at a rock concert where the level of noise exposure is 100 dB and you are wearing earplugs with an NRR 33dB, your level of exposure would not be reduced to 67 dB. Instead, to determine the actual amount of decibel deduction applied (when decibels are measured dBA which is the most common), you take the NRR number (in dB), subtract seven, and then divide by two. Given the previous example, your noise reduction equation would look like the following: (33-7)/2 = 13. This means that if you are at a rock concert with a level of noise exposure at 100 dB and you are wearing a hearing protector with an NRR 33 dB, your new level of noise exposure is 87 dB. If you are wearing a product with an NRR of 27 it would deduct 10 decibels (27-7/2=10).

*To maximize noise reduction, hearing protectors must be worn properly.

How does wearing dual hearing protectors change NRR?
When hearing protectors are worn in combination (i.e. earplugs AND earmuffs), rather than adding the two NRR numbers together, you simply add five more decibels of protection to the device with the higher NRR. For example, using 3M™ E-A-R™ Classic Earplugs (NRR 29) with 3M™ Peltor™ H7 Deluxe Earmuffs (NRR 27) would provide a Noise Reduction Rating of approximately 34 decibels.

Thanks for this @gav01. It's important to know that you shouldn't put complete stock in the NRR ratings. But I don't know that I buy this formula either. I mean, I have a pair of EarPeace plugs with three filters rated at 11 dB (low attenuation), 14 dB (medium attenuation) and 19 dB (max attenuation). I love them - they work great in everyday scenarios up to 85-95 dB or so. But according to this formula, I would only get the following true attenuation levels:

Low: 11 - 7 / 2 = 2 dB
Med: 14 - 7 / 2 = 3.5 dB
High: 19 - 7 / 2 = 6 dB

From my own experience, it seems implausible to suggest that these things only cut 2 or 3 dB of sound. I mean, I can practically get that just by waving my hand in front of my face. So it's hard for me to believe that this formula holds in all situations.

Does anyone know more regarding this?