Ear Protection

[Manco]

You've really got to know how the spec is generated to know whether it is useful or not.

For example if the NRR rating is the max noise reduction it is essentially meaningless. Say the time the boom from your gun lasts is 10msecs. Assume that at 5ms the db of the boom is 165db (not uncommon). At 3ms the boom might be at 120db. If the response time of the electronics to achieve that 33db NRR is 7msecs then you really don't get 33db NRR. The max your ears are exposed to is what ever the NRR is at 5msecs which is when the example assumed peak noise level is reached.

I don't quite understand what you're saying. Isn't the NRR only for the passive, non-electronic function of the muffs? (i.e. when the electronics are off) In a fancy set like this, the electronics would then apply dynamic range compression to the sound its microphones pick up and reproduce it at whatever volume level you set, rather than cutting in and out like cheap electronics would. There may be a short, constant, fixed delay added to the sound because of the processing, but if implemented properly it's not going to allow any excessively loud sounds to be reproduced (the built-in speakers can only play so loud anyway). Am I missing something here?

If it takes the electronics less then the example of 5msecs to reach the 33NRR level then you're good to go but as long as the response time is longer than it takes for the boom to achieve max db level then you're not getting the published NRR. Cheap electronics typically take longer to achieve max NRR than good electronics which quite often is directly correlated to the price you pay for those electronic ears.

Is the published NRR really related to the function of the electronics? What happens when the electronics are off? Would the NRR then be higher?

 

[Ragnar Danneskjold]

I use the electronic muffling earphones when I am just do skill building, but when I'm doing field training I use some tan insertables. Train how you fight.

 

[Werewolf]

I don't quite understand what you're saying. Isn't the NRR only for the passive, non-electronic function of the muffs?

It is my understanding that the NRR rating of electronic muffs is the combined noise reduction of the passive muff and the electronic cut off.

You may be correct about it being just the passive muff (and for the cheaper/most electronic muffs probably are) but IMO that rating would short change the muff. It's total NRR that counts else why pay for the electronics? It's the electronics that block the boom of the gun. They may just turn the speaker sound off which is what the cheaper muffs do or on the more expensive models may actually generate a sound 180 degrees out of phase to cancel the boom entirely which makes the effective NRR more than just the passive NRR of the muffs as that is a simple reduction of the boom and not an almost complete cancelation of it.

I think my Peltor 7S is one of the muffs that uses cancelation as when any loud sound goes off (clapping of hands for example) the sound seems to go completely away. I can't be certain but when firing my guns the boom of the gun seems to be gone not just reduced to what ever level the passive muff would let thru. That can only happen with cancellation.

Then again that may just be perception or wishful thinking on my part.

I'm sooooooo confused...

 

[Manco]

You may be correct about it being just the passive muff (and for the cheaper/most electronic muffs probably are) but IMO that rating would short change the muff. It's total NRR that counts else why pay for the electronics? It's the electronics that block the boom of the gun.

OK, this is where our understandings or assumptions differ. I've always assumed that the muff only passively isolates one's ears from noise, and that the electronics are there only to "decide" what noise (and how loud) will be reproduced by speakers inside the muffs (effectively acting as a filter). Cheaper electronics have simple circuits that cut out completely or reduce to a very low volume whenever there are loud sounds, allowing you to hear speech at normal volume in between shots, while expensive electronics scale all loud sounds down to tolerable levels while preserving the volume of quieter sounds, allowing you to hear clear speech at all times (fairly simple in mathematical terms but requires far more complex processing to achieve).

Additionally, perhaps one reason cheaper muffs tend to have lower NRRs is that the electronics themselves, including microphones and wires, physically compromise the sonic integrity of the muffs. It may therefore be very difficult and expensive to design electronic muffs that can block sound passively as well as good non-electronic muffs.

That's my understanding, anyway.

They may just turn the speaker sound off which is what the cheaper muffs do or on the more expensive models may actually generate a sound 180 degrees out of phase to cancel the boom entirely which makes the effective NRR more than just the passive NRR of the muffs as that is a simple reduction of the boom and not an almost complete cancelation of it.

I think my Peltor 7S is one of the muffs that uses cancelation as when any loud sound goes off (clapping of hands for example) the sound seems to go completely away. I can't be certain but when firing my guns the boom of the gun seems to be gone not just reduced to what ever level the passive muff would let thru. That can only happen with cancellation.

Then again that may just be perception or wishful thinking on my part.

I'm sooooooo confused...

I understand what you mean now, and the reason I hadn't thought of it was that the amount of instantaneous power that would be required would seem to place great strain on the batteries and be very demanding (maybe too demanding) on components, as we're not talking about music headphones canceling conversation or street noise here. That said, on second thought it would only be in addition to some heavy-duty sound shielding, so maybe you're right. However, I just checked the Pro Ears and Peltor websites, and neither mentioned anything about active cancellation. The Pro Ears site does mention dynamic range compression and various other electronic filtering that goes on, which has to be at least one of the differences between high-end and low-end electronics muffs:

http://www.pro-ears.com/technology

 

[Yosemite Sam]

It makes more sense that the only noise reduction is done passively, whether it's non-electronic earmuffs, electronic earmuffs, or ear plugs. The NRR is based completely on how well the material physically attenuates noise, and NRR is some kind of "average" reduction rating across multiple frequencies. So 33 db NRR doesn't mean 33 db at low-frequencies (100 Hz) as it is for 8000 Hz.

I think all the electronics do is amplify your surroundings, period. Some do it better than others. So basically the hearing protection part is done 24/7 and doesn't need batteries, but if you want to hear your surroundings, you'll need the electronics to pick and choose what to amplify.

--------------

I think the confusion is because in the audio and music world, companies like Bose and Sony make noise-canceling headphones, where the electronics produce destructive interference (frequencies out of phase) which actually cancel noise from the surrounding. So in the music world, the earmuffs provide both passive AND active (electronic) noise canceling. But in the shooting world, the earmuffs provide only passive sound protection, and the electronics are just icing on the cake to amplify sounds. It's the opposite goal.

 

[blutarsky]

i have a couple sets of the howard leight impact sport muffs -- i like them, a lot. they're awesome for outdoor shooting, although i'm only usually with at most 3-4 others at the range and nobody i've been near was shooting excessively loud stuff (well, aside from .357 and assorted 12ga... which isn't all that quiet). they're delightful when you're with your friends and can still chat without yelling. when i've shot indoors, i've doubled-up with foam earplugs with my electronic muffs on top turned most of the way up. that makes it a lot easier to hear instructions or chatter while also adding critical extra protection of the plugs in the confined space.

 

[Manco]

when i've shot indoors, i've doubled-up with foam earplugs with my electronic muffs on top turned most of the way up. that makes it a lot easier to hear instructions or chatter while also adding critical extra protection of the plugs in the confined space.

That's an excellent setup to use, and I've always doubled-up myself because I have relatively sensitive hearing, but at one point I made what I think is a weird discovery: lots of loud sounds can cause me physical pain, but gunshots just don't seem nearly as loud as expected to me, even indoors. To give you some context, movie theater volume levels are sometimes uncomfortable to the point where I have to cover my ears, I can't bear the volume of rock concerts even with hearing protection (I walked out of the only concert I've ever attended even though I was wearing high-NRR plugs), and smoke alarms (which occasionally go off when heavy cooking is going on) hurt so much that I need muffs to get close enough to silence them. My sister thinks I'm such a wimp as a result, as she doesn't have any such issues (even attends rock concerts without hearing protection ), but one time we went shooting together at an indoor range and decided not to double-up (wearing only muffs) so that we could sort of better gauge, in relative terms, how loud discharging a firearm indoors could be in a defensive situation, and she kept complaining about how LOUD the shots were while I wasn't bothered in the least (we were shooting .40 S&W). I even broke the seal on my muffs and slightly displaced them for a couple of shots, and it still didn't seem all that loud. After we were done shooting, my ears felt great and I could hear perfectly fine, like I just walked out of a library. Obviously everybody is different, but this still seems nuts! I will still take the same precautions I always have, regardless, but for some reason I'm relatively insensitive to the sound of gunshots.

 

[ar10]

I think my Peltor 7S is one of the muffs that uses cancelation as when any loud sound goes off (clapping of hands for example) the sound seems to go completely away. I can't be certain but when firing my guns the boom of the gun seems to be gone not just reduced to what ever level the passive muff would let thru. That can only happen with cancellation.

I have a set of Peltors, (don't know the model but they have the orange caps), and they're the best muffs I've ever had. I know nothing about NRR, RMS, or any of the other technical information. But the biggest advantage they have is the small batteries and the way I can hear individuals on the range talking at the same time shooters are firing their weapons. If I'm watching a new shooter I can hear the conversation of shooters 2~3 bays over.

I have been considering getting a set of those "Pro Ears", (I think that's the name), but they're about 500~600.00 ea

 

[WoofersInc]

For example if the NRR rating is the max noise reduction it is essentially meaningless. Say the time the boom from your gun lasts is 10msecs. Assume that at 5ms the db of the boom is 165db (not uncommon). At 3ms the boom might be at 120db. If the response time of the electronics to achieve that 33db NRR is 7msecs then you really don't get 33db NRR. The max your ears are exposed to is what ever the NRR is at 5msecs which is when the example assumed peak noise level is reached. If it takes the electronics less then the example of 5msecs to reach the 33NRR level then you're good to go but as long as the response time is longer than it takes for the boom to achieve max db level then you're not getting the published NRR.

This is directly from Pro-Ears website.

Fast 'Attack Time'
With a reaction and recovery time of 1.5 milliseconds, less than a typical pause between words in normal conversation, the system greatly enhances your awareness of your environment while simultaneously protects your hearing from loud noise.

Also this

Only Pro Ears models of electronic hearing protection/amplification muffs feature 'DLSC™' Dynamic Level Sound Compression Technology. This superior technology allows the wearer to hear every sound even during high volume noise spikes. While other brands say they have 'compression' technology, they do not. What they do have is outdated technology, either 'Peak Clipping' or 'Automatic Level Control'. 'Peak Clipping' turns the amplification system off when noise levels reach a preset decibel leaving the wearer with passive muffs. 'ALC' simply reacts to high noise levels by lowering the unit's volume so the louder sounds still drown out softer sounds. In both technologies loud noise levels compromise the ability to hear quieter sounds. Only Ridgeline's 'DLSC' technology protects hearing while at the same time allowing the wearer to hear lower volume sounds such as normal conversation. 'DLSC' works by instantly 'compressing' all noises over the 70 dB threshold by 50% to a safe level while amplifying all sounds below that to 70 dB. The result is the wearer will hear everything, including conversation, while simultaneously being protected from dangerous, high volume sounds.





Block 1 - Gain and Volume Control
This block amplifies the microphone. The gain can be adjusted from 0 dB to 40 dB.

Block 2 - High Pass Filters
Cuts the low frequencies below 300Hz, eliminating most of the wind noise and other low frequencies.

Block 3 - Dynamic Level Sound Compression (DLSC™)
This circuit automatically adjusts or compresses the input signal by as much as 45 dB. The DLSC will automatically adjust the internal gain in order to maintain the safe output level of 85 dB.

Block 4 - Low Pass Filters
Limits the high frequencies that are allowed to pass. The 3 dB point is at 5Khz.

Block 5 - Speaker Amp
This stage provides the high output current required to drive the speaker with no distortion.

The Dual Layer, Printed Circuit Boards with extensive ground planes make it immune to interferences caused by Radios, TV, Ham stations and other sources. The All-Surface Mount Design uses the highest quality parts available and is based on five, low power Integrated Circuits allowing the unit to consume less than 4 Ma with a battery life of more than 200 hours.

http://www.pro-ears.com/features

Having used these I know that they just flat out work.

 

[fractal7]

Howard Leight

Another vote for the Howard Leight muffs. I got a pair last summer and have loved them. The volume is very adjustable and they just damp out sound rather than clicking off (which I like but some people consider a "con"). Also they have a headphone in jack so you can use them on a plane to drown out noise and crank up as headphones.