ANR/ENR... Great, damaging or both?

[betr_thn_Icarus]

I'm looking for people who have used noise reduction for a while to chime in as well as new people to the NR headsets.

 

I have been looking into headsets a little recently. ANR and ENR just doesn't seem to make sense to me. I understand these headsets have a base passive noise reduction for a minimum protection.

 

ANR and ENR work by sensing the noise that makes it into your ear cup then reproducing an equal and opposite signal of the same amplitude or size. I'll use my electronics degree on this...This does not actually cancel out the noise it actually doubles the noise....it basically doubles the frequency and creates a higher frequency by doing this. Bass is a slow sine wave and treble is a fast high frequency wave (more cycles per second). They may just be moving the frequency into a less audible area of our hearing spectrum. We used to automatically adjust electronics designs the same way to prevent similar frequencies from interfering. By moving the frequency up they could actually be doing some damage to your upper range of hearing. I have heard talk of this before.

 

Other opinions? What is the real experience of people who have used these in a high noise environment for a long time?

[Pogue]

Other opinions? What is the real experience of people who have used these in a high noise environment for a long time?

I'm no expert, but I didn't think they double the frequency, I think they duplicate the same frequency 180 degrees out of phase, so in theory if signal 'A' has a 100 dB peak at 90 degrees and signal 'B' has a 100 dB peak at 270 degrees assuming they're of the same waveform and amplitude the average amplitude will be zero. How effective noise canceling headsets are is going to be based on what their frequency response is, i.e., if they aren't effectiive at 16kHz you may not hear it but it's causing damage, and how quickly the system responds to transient spikes. I own the Bose Quiet Comfort headset for listening to tunes as a passenger, and it works OK, but I prefer passive David Clarks with CEP's installed for flying.

[tattooed]

Interesting topic. My own experience is this. I took my 1st helicopter flight with a buddy of mine who just got his private (this was back in August, I think). He has a Bose, and I used a David Clark. By time we landed about a hour later, my head was pounding, my ears ringing. For the return leg home, we switched (since I was planning on going to flight school, he wanted to introduce me to Bose).

The ride home was far more pleasant, no ringing, and the pounding headache gone. Much more relaxing.

 

I'll have to ask my geeky electrical engineer husband about the sine and db...I took alot of high level math, so I have a clue, but no actual training in wave theory. In college I had my own oscilloscope, and ran everything I owned thru it...just for fun. A true geek.

 

I share my above experience, because I am VERY sensitive to sounds, music and layering of sounds. I can hear the high-pitch electrical whine of electronics, and I get headaches easily from too much "input". I obviously ran out and bought a Bose. I love it.

I'd probably agree with pogue, that they really do "cancel" the nose. I know you can filter out frequencies...I imagine that is what technology they are using.

I'm interested in people's responses and research.

[Copterpilot213]

From Bose's website:

 

"Bose Acoustic Noise Cancelling® headset circuitry monitors sound at the ear, identifies unwanted noise and creates an out-of-phase signal to reduce it. Our active equalization circuitry delivers clean, full sound with improved intelligibility of radio and intercom audio. In fact, US Air Force tests with our Acoustic Noise Cancelling headsets achieved intelligibility scores of 95% at 115db."

 

(There is a javascript link for more information about the noise cancelling that I cannot copy and paste)

 

http://www.bose.com/controller?event=VIEW_..._index&ck=0

[Node]

I've been using the Bose for a couple of years and I can't speak for others, but I don't use any other headset unless I'm forced to. I had similar experience as tattooed, used the DC's at the beginning of my training, and got a lot of fatigue and headaches. Switched to the Bose and problem solved. I've used other people headsets and really haven't had one I liked better than the Bose. As for hearing loss....well my wife doesn't have to throw anything at me every time she wants to have a conversation. Well that does happen on occasion, but its not because I can't hear her! ummmm, you asked me to do what.....?

[West Coaster]

I have ANR in my helmet and swear by it. When it's not turned on I notice immediately, and once I flick the switch it's like hitting the mute button on a TV. The only engine noise left to be heard it the higher frequency stuff, but with the helmet it's barely noticebale. On long flights the ANR is worth it's weight in gold as the reduction in low freq. noises greatly helps reduce fatigue.

 

Heard some complain about the Bose X saying that with the reduced low freq. noise, the remaining high freq. stuff drives them bonkers in a turbine. But all the guys I work with who use the Bose X love it. People flying piston machines would greatly appreciate it's ability to reduce most of the engine noise.

[palmfish]

Here's my $0.02.

 

I have sufferred from noise-induced hearing loss (tinnitus) for many years and am extremely sensitive to noise (I get headaches and fatigue when exposed to even moderate noise for any length of time). I too was concerned that ANR might be damaging my hearing by masking noise without reducing the actual force of the wave.

 

I did some research and found several good explanations that allayed my fears. Here's one digestible explanation:

 

http://en.wikipedia.org/wiki/Active_noise_control

 

Basically, since sound is a pressure wave, as long as the ANR signal is equal to and opposite of the incoming wave, then the wave will cease to exist (be cancelled).

 

But I agree with the poster above - I enjoy my ANR Bose QC2 headphones when I'm a passenger on a commercial flight, but not when I'm in the cockpit. I have used David Clark ANR and Bose Aviation X headsets, and in my experience, I have found that ANR aviation headsets do make communications clearer and more intelligible, but they are only marginally "quieter" than a good passive headset. I also think that some frequencies are "louder" inside an ANR headset, but I have no proof - just perception.

 

In any case, without in-the-ear protection, I experience headache and fatigue no matter what technology I use. That's why I have found CEP's to be a life (and hearing) saver. I won't fly without them.

Edited March 15, 2008 by palmfish

[captkirkyota]

Searched for CEP and came up with nothing, I am pretty sure someone before has mentioned them, but i don't remember, so what are CEP's?

[Pogue]

Searched for CEP and came up with nothing, I am pretty sure someone before has mentioned them, but i don't remember, so what are CEP's?

Communications Ear Plugs - try http://www.cep-usa.com

[Gomer Pylot]

Communications Ear Plugs - try http://www.cep-usa.com

CEPs are the basis for lightweight headsets, and are also used in helmets and regular headsets. They give higher NRR ratings than any ANR headset, provided properly fitted earplugs are used. They give excellent passive protection, don't need batteries, and are very comfortable, at least for me. I don't like ANR headsets because they're very uncomfortable to me, pressing on my ears and causing a lot of pain over time. There are lots of headset choices, and they all seem to work for some people. It's a matter of choice. I do think the ANR headsets can cause high-frequency hearing damage, because they simply can't mask high-frequency noise, becaue the frequency is too high, and the electronics just can't work fast enough to cancel it. They seem to work well on low-frequency noise, but the higher the frequency, the less effective they are, and this can be seen in the NRR numbers. Passive protection is essential.

[captkirkyota]

Communications Ear Plugs - try http://www.cep-usa.com

 

Ah, those are what my clarity aloft headsets used. I LOVED that headset, even better than my Bose X. But the inability to move the mic from one side to the other to reduce wind from activating the mic led me to return them.

 

Thanks.

[betr_thn_Icarus]

All very interesting thanks everyone....it is too bad I can't rent some first.

[PhotoFlyer]

Ask around, I guarantee there is somebody nearby who would let you try their Bose/Lightspeed/DC ENC/whatever. Also check out the avionics shops near you. Most sell headsets and will have some you can try. Also, there are multiple bose stores, including a factory outlet, which should all have the Bose X. If I lived nearby I'd let you try mine, but I am a little far away for that...

 

Search for a bose store

[Helo-Pilot]

Bose does have a 'try it free for 30 days' policy.

 

http://www.bose.com/controller?event=VIEW_..._index&ck=0

[500E]

Have a look at the in ear units, like Lightspeed Mach1. there are 3 or 4 of of the same type I think Gomer pilot uses an in ear all the time.

Custom ear plugs make a real difference as well.

[Gomer Pylot]

There are a number of companies that offer a 30-day guarantee. You can try the headset and return it if you don't like it. You may have to pay for the return shipping, but that's cheap rental.

 

Captkirkyota, take a look at the Quiet Technologies Auricomm Pro. You can wear it in either ear, unlike their HALO or the Clarity Aloft.

[captkirkyota]

There are a number of companies that offer a 30-day guarantee. You can try the headset and return it if you don't like it. You may have to pay for the return shipping, but that's cheap rental.

 

Captkirkyota, take a look at the Quiet Technologies Auricomm Pro. You can wear it in either ear, unlike their HALO or the Clarity Aloft.

 

cool, will look into those. Thanks GP.

[CROOK]

CEP Kit!!!!!!!!!!!!!!!

 

Will make you go from to

 

In just a few easy steps.... No really they are great. I have tried Bose and they don't do well with the turbine noise. Plus I never have to change any batteries. I think the only reason to get a bose is if you are having real problems with the weight of your headset and can fly without discomfort with a DavidCark or similar.

 

CROOK

[captkirkyota]

There are a number of companies that offer a 30-day guarantee. You can try the headset and return it if you don't like it. You may have to pay for the return shipping, but that's cheap rental.

 

Captkirkyota, take a look at the Quiet Technologies Auricomm Pro. You can wear it in either ear, unlike their HALO or the Clarity Aloft.

 

 

Just placed an order for these GP, will let you know if these don't slip and fall down like the Mach 1 lightspeed ones did, and if the mic does not always get activated by wind like the Clarity aloft ones did.

 

If they work, I'll have a set of Bose for sale, only used for 6 months.

 

Thanks for linking those.