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I have read that passive hearing protection (standard earmuffs/plugs) offer good protection against higher frequency noise but do not protect as well at lower frequencies. Supposedly active noise reduction (ANR) can attenuate low frequency noise. Does any hearing protection worn by professionals in aviation (airports, military roles, etc.) anywhere in the world use ANR or is it all passive?

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  • $\begingroup$ ANR can attenuate low frequency noise indeed, is mainly effective on constant or slow changing noises. $\endgroup$
    – Koyovis
    Sep 7 at 8:41
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    $\begingroup$ Are you asking about about pilots (headsets used in the cockpit) or ground crew? $\endgroup$
    – Bianfable
    Sep 7 at 9:56
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    $\begingroup$ As a backup/supplement to ANR, I make my own low frequency earplugs by wrapping 3M Push-Ins with a few inches of lead foil tape (used for ballasting golf clubs) around the shaft, covering the cylinder of tape with heat shrink. They attenuate under 200 Hz incredibly well, at least as good as the ANR. Light a/c are mostly 60-100 Hz. $\endgroup$
    – John K
    Sep 7 at 12:58
  • $\begingroup$ @JohnK, color me intrigued. Do you have some pics? $\endgroup$ Sep 7 at 22:56
  • $\begingroup$ @KennSebesta See answer posted below. $\endgroup$
    – John K
    Sep 8 at 1:38
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If you're talking about crew/pilot headsets then ANR is a very popular option - especially in General Aviation. The Bose A20 is probably the most popular headset, but both Lightspeed and David Clark also sell ANR headsets for professional aviation

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    $\begingroup$ My recollection is that the first Bose aviation headsets were actually the first mass produced ANR at all. Other consumer products then followed. $\endgroup$
    – Adam
    Sep 7 at 20:45
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Adding to the civilian answers, the F-22 helmet and F-35 helmet do include Active Noise Reduction technology. I believe most other US military fighter jets rely on passive noise reduction; this may be in part because ANR technology didn't really hit mainstream use until the 1980s, while many of the fighters in service with the US today (F-15, F-16, F-18, A-10, EA-6) began production in the 1970s or earlier.

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Not quite on topic, but you if you don't have ANR units you can make very effective low frequency earplugs without spending a fortune on Flare Audio Isolate aluminum earplugs (I bought a set for 40 bucks and promptly lost them, although they do work). The metal core of the Isolates helps the foam earplug part attenuate low frequencies quite well. If aluminum = good, lead must = better!

So I just got some 3M Push-Ins earplugs, the kind with the blue plastic shaft and a yellow bulb, some lead foil tape used for ballast on golf clubs from a golf supply store, and some quarter inch heat shrink. If you're concerned about lead encased in heat shrink in your outer ear canal, you can also use aluminum or stainless steel foil tape for somewhat less attenuation.

Wrap a 2-3 inch length of tape around the shaft (depending how thick you want them, which depends on how wide your ear canal is), cover with heat shrink and shrink it over (I put the bulb part into a piece of metal tubing the diameter of the bulb to protect it from the heat gun).

I tested them in using stereo headphones cranked way up with low frequency sounds playing, comparing them in opposite ears against foam plugs and the Isolates (before I lost them). These plugs attenuate the 60-70 hz noise from propeller and exhaust extremely well, better than the isolates did I would say. Above 200 Hz, they seem to be about the same as foam plugs, but the under 100 Hz noise is most of the sound in the cockpit.

I wear them under my Dave Clark ANR conversion headset (a kit from Headsets Incorporated I got to convert my 45 year old Dave Clarks) and can't really tell if the ANR is on or off.

Another tip for improving the performance of earplugs in general is to carry around a tube of lanolin (for baby bottoms) in your flight bag and apply it to the foam. They go in easier, and seal better.

enter image description here

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    $\begingroup$ I'm not sure where the actual lead in that picture so I don't know if it's valid, but my concern with this setup would be exposure to lead. $\endgroup$
    – Michael
    Sep 8 at 1:47
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    $\begingroup$ The shiny silver tape is lead tape. It's about .010" with adhesive backing. Anyway, you're not supposed to eat it, and I normally don't have a lot of fluids oozing from my ears. You could use aluminum or steel tape, although the attenuation you get will be lower. $\endgroup$
    – John K
    Sep 8 at 3:55
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    $\begingroup$ Your ears constantly, continually, generate fluids. $\endgroup$
    – Fattie
    Sep 8 at 11:16
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    $\begingroup$ Not oozing out. Unless you have an infection. $\endgroup$
    – John K
    Sep 8 at 12:27
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    $\begingroup$ In case anyone wondered what's going on here: the inertia of the metal does the job at low frequencies. That's where the entire plug acts like a rigid body and just moves back and forth under sound pressure. So making it heavier does the trick. I'd personally cover that lead tape in a water-tight adhesive-lined shrink tube for extra protection, and avoid contaminating it with fingers that touched lead - they carry lots! You can use a surface lead test kit to get a sample from ear canal to test for lead. Goal is for there to be nothing detectable. A copper tape will work well instead :) $\endgroup$ Sep 8 at 17:26
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Yes, they are used. You can just Google active noise-cancelling aviation headset to get a sample of many different models. I personally own a Lightspeed Zulu 3. I will also get a Bose A20 when I get back into flying.

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Yes, it's extremely common, both with pilots and with passengers.

As other answers have mentioned, ANC headsets like the Bose A20 are very common with pilots. ANC is especially wonderful for light aircraft where you're sitting a few feet from the engine and often directly behind it. Light aircraft cabins don't provide nearly as much dampening/isolation of engine vibrations as something like an airliner, so the noise levels are quite high and hearing protection is a must. Even those who don't use headsets with active noise cancellation use ones with significant noise-isolating cups that fit tightly around your ears.

Aside from pilots, though, even passengers on commercial flights very frequently use ANC headphones. Many airlines provide ANC headphones to passengers in business and first class on their aircraft that are equipped for long-haul flights. Aside from ones provided by the airline, though, ANC headphones are very common with frequent flyers. The Bose and Sony ones are particularly common. I use the Bose QC35s myself when flying commercial, regardless of what cabin I'm in, as I generally find them to be better than the ANC headphones that the airlines provide. They're wonderful at reducing engine noise, even when you're sitting right beside the engine. They also help significantly for cutting down on cabin noise and are much more comfortable to wear for extended periods than headsets that have tight-fitting noise isolation cups around your ears.

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