About Bose A20 headset

[alexc]

I am about to buy a better headset to protect my hearing. I tried a noise canceling headset before (I wasn't sure if it was a Bose headset), it seemed to be very quiet. I actually like to hear some sounds from the engine and blades, as long as it's not too loud, also, if something goes wrong, I can hear it, so I am afraid that Bose A20 headset will be too quiet? Any suggestions?

[pilot#476398]

None of them will be too quiet! Funny though the first thing I noticed when I switched to ANR (Zulu for me, but I've also used the A20) were new sounds I'd never heard before!

Edited November 27, 2013 by pilot#476398

[aeroscout]

I bought the David Clark H10-56. I was looking for passive noise reduction. It was rated the highest in that category of all the manufacturers and models I looked at.

I didn't want the constant battery switching of the anr models.

I'm not sure of the long term effects on hearing of ANRs anyway.

I didn't want the extra time it takes for CEPs to be put on and taken off.

[pilot#476398]

Before I switched to the Zulu I had the DC H10-66. Its the same NRR as the 56, only it has a high/low switch on the mic. Great headsets, if you want to go passive!

[rotormandan]

I allways wonder how well they protect your hearing since noise cancelling basically adds a 2nd frequency to cancel out the sounds coming in. It's nice thought. I use a lightspeed and I like it.

[rotormandan]

I allways wonder how well they protect your hearing since noise cancelling basically adds a 2nd frequency to cancel out the sounds coming in. It's nice thought. I use a lightspeed and I like it.

[WolftalonID]

Interesting topic. There have been many studies into sound cancelling headsets over the years. In the early years, ANR was not as effective as it has become today. However you look at the evolution of ANR, its design is to cancel out low frequency sound by using an out of phase sound wave to eliminate the sound.

Sound waves are percussion like. That means they act like a piston to creat what we hear. Think about that desk top toy with the five ball bearings suspended by a string. You swing the outside ball, it hits the rest but only the other end moves. No movement occurs in the middle.

Now I know that is completly different physics, just trying to paint a picture of sorts. The better picture would be something I recently saw at my boys field trip to the local Discovery center. A spring held taunt and one end shook the spring at a variable frequency. There were spots along the spring that were still while the rest was a blur of movement. This was a demo of how sound waves worked and how they cancel out when pushed against each other.

 

Most people think sound waves are sine like,( the effect of whipping a rope up and down ), this is where the confusion occures of thinking ANR can damage hearing.

The truth is that even with ANR, we can have our hearing damaged due to high frequency sound that the ANR is not addressing. The only way your going to block that is from good passive sound control. Most headsets today offer a level of passive along with the ANR aspect. You can also choose to use ear plugs under your headset to assit.

 

In our GA trainers with piston engines, we dont expose ourselves to a whole lot of high frequency sound, in comparison to a helo that is running a turbine engine or two over your head.

 

So have faith in your ANR that it is protecting you from damaged hearing by blocking those dreded low freqency waves....and if your really needing the best protection add some earplugs under them.

 

I personally use the Lightspeed Zulu 2 and keep two extra batteries in my kneeboard. I also time limit my batteries to 25 flight hours and then change them. Since tracking their flight hours, I have yet to have a set die in flight.

Edited November 27, 2013 by WolftalonID

[rotornut67]

I have 2 sets of the Zulu 2's and one set of Bose X. I like the Zulus better mainly due to the fit (they don't squish my ears inside the cups), but both work extremely well. I have gotten as much as 58 hours on a set of batteries in the Zulu, but like Wolf said above, be ready to change them anytime after 25 or 30 hours. I would like to try a set of the Bose A20s.

[aeroscout]

My thoughts on ANR hearing protection are that there is enough of a delay in the noise canceling process that both sound waves wear on your hearing mechanisms even though at the perception level they seem to cancel.

I don't know this to be true, but I don't think ANR has been around long enough to evaluate the long term effects, if any.

[pilot#476398]

I wear plugs plugs under my Zulu, just in case!

[LSA]

Luke from Lightspeed Aviation here. We’d like to add to the great comments already supplied about ANR technology.

 

• Does the noise reducing signal cause ear damage?

• No. Sound is actually a compression wave in the air. The noise, or first wave, compresses to an amount greater than normal air pressure. The cancelling noise, or second wave has a pressure of less than normal air pressure. When the two waves collide, they equalize, thus reducing the air pressure on your ear.

• By cancelling the interfering noises, we can actually increase hearing safety by allowing internal headset volume to be set at a lower level.

 

• Wearing ear plugs/audio devices under an ANR headset?

• The result is actually reduced performance. While there are some very rare and extreme cases where noise is so loud that no headset would be enough alone, earplugs could be a useful advantage. Otherwise, you risk sacrificing some of the benefit of the ANR signal processing when wearing earplugs.

[alexc]

thanks very much!
Is there any initial mic delay when you start talking to control tower for ANC headset?

[heligirl03]

No mic delay difference. There is a reason they are so popular. The BOSE X earcups were always too small, sat on top of your ears instead of encompassing them...not comfy for more than an hour or two a day at most. The A20 fixed that problem with much bigger earcups, I've worn them 8hrs/day on multiple consecutive days with no second thought. It's been said before, but to save you digging thru umpteen threads...if you have a large head you'll likely want a Zulu. I've had BOSE for years, the X and then the A20, and they worked great for me and my pinhead. I can't get a seal around the jawline with a Zulu, they're too wide with that pretty, rounded metal yoke. By contrast, the V design of the BOSE yoke gets complaints for pinching big craniums. These days I'm in a helmet and CEPs, no complaints there either. Ask someone to borrow theirs to comparison shop for a minute or an hour, get an idea before you shell out the dough

 

HG03

[aeroscout]

I wear plugs plugs under my Zulu, just in case!

You are wise, grasshopper.

[alexc]

Thanks for all the replies.

 

I finally bought Bose A20 and used it in several flights. I am writing my review here, which may be useful for future ANC headset buyers who have the same question.

 

In short, I wish I had bought A20 or some other ANC headset from day 1. I recommend you to buy an ANC headset as soon as you can.

 

A20 is a very comfortable headset, very effective at noise canceling. Helicopter noise is mostly canceled out. You can still hear the engine and rotors mechanical sound, which is good for situation awareness, all the filtered sounds are at a very comfortable level. It pretty much cancels out what you don't need to hear and leaves what you need to hear.

 

The battery is not a problem, doesn't bother me. Tower communication is also more clear.

 

I also compared it to Bose QuietComfort 15, just for curiosity. I found that they are very similar, but A20 has larger power, i.e, more heavy duty, which makes sense for helicopter use.

 

After I received A20, I tested A20 in my room first to filter out the noise in my room. When I turned on the A20 in my room, I could feel some pressure change in my ear, it felt like you were listening under the water or the ear popping when an airplane is taking off and climbing. I checked some references, some people said that the change of pressure feeling is a hearing illusion. From physics wave equation, it also shows zero impact on the sound field when the sounds cancel each other. I guess you have to ask the headset engineer to find the true answer. I feel it is a little bit uncomfortable due to this pressure change in my room, so I had some concern before I used it for actual helicopter flying. The truth is that when I use it during helicopter flying, I don't feel this discomfort. I feel perfect. It may be because the helicopter noise is so so much larger, so I don't feel the impact at all.

 

But anyway, in case you have any doubt about ANC because you read online that ANC headsets make you feel ear popping, but my experience tells me that it is not an issue at all when you use it during actual helicopter flying. The benefit is much much bigger than the cons if there are any at all.

[HeliNomad]

Love my Zulu 2s in the EC. I've noticed that proper fit is huge with the noise canceling effectiveness. Audio is also really good over streaming Bluetooth. A20s are nice but the Zulu2 IMO beat them slightly in build quality and comfort for my head.

[Jaybee]

A big thing to remember is, headsets are a personal thing ! Seriously ! I believe this is seriously overlooked. What works for head shape A does not work for head shape B.

 

I got a chance to borrow and try out both Zulu 2 and Bose A20 on several occasions for multiple hours. That is the only way you will really know.

 

First of all I was happy with my David Clamp passives. Really liked my buddies Zulus and was close to buying a set. Tried the A20 and they just fit more comfortably on my head than the Zulus.

 

Financially, I'm still sporting the David Clamps. When I get around to buying some replacements, I'll make sure and test drive them before I buy whatever is available at the time.

[avbug]

ANR enhances your ability to hear and interpret communication. It does not increase hearing protection, and in that respect, because it addresses a narrow frequency range, it gives the illusion of hearing protection.

[iChris]

“The presently available analog ANR hearing protectors are without any doubt helpful in many situations. However, for some situations, it could be helpful to use more flexible digital ANR devices. In some situations, e.g. ground personnel around jet airplanes, present ANR hearing protectors do not add any protection, in contrary the noise exposure could even increase.”

 

“By the 1970s the performance of such devices, particularly those used in military applications, had been best optimized for use with the types of cranial protection being worn by soldiers, sailors, and aircrew. Since that time the major thrust in hearing protection enhancement has been the development and integration of Active Noise Reduction (ANR) systems where an electronic circuit is incorporated into the device to provide additional active attenuation in addition to the passive attenuation. ANR has provided significant benefits in low frequency attenuation and provides complementary performance to the passive device. However, for future military noise environments ANR headsets and ANR earplugs will not individually provide sufficient levels of protection, and passive earplugs and earmuffs may have to be used in some combination to provide adequate hearing protection.”

 

“When military personnel are exposed to noise with high levels having a very strong low frequency component (armored vehicles, helicopters, propeller driven airplanes…) ANR headsets are a good choice as personnel hearing protector. With the help of the ANR system (complementary to the passive protection of the headset by itself) the efficiency of the soldier is increased. In the frequency range below 500 Hz an ANR headset has an insertion loss that is about 15-20 dB better than a standard hearing protection.”

 

“Personnel may be exposed to such high levels, that the performance of standard single or double passive hearing protection (ear cups and/or earmuffs) is not enough. Considering the requirements for such protection devices, only ANR earplugs (personal fit if possible) may be suitable. These future devices have to be designed in a way, that the contribution of the ANR at 3 KHz (and higher if possible) should not be less than 7 dB and not less than 10 dB for frequencies lower than 1.5 kHz. There is still some technical challenge to reach this performance. Once arrived at this protection level, the next step for better hearing protection will be the limitation of bone conduction.”

 

NATO RESEARCH AND TECHNOLOGY ORGANISATION

 

2-1 Passive Hearing Protection Systems and their Performance

by R. McKinley and V. Bjorn

 

3-1 Active Hearing Protection Systems and their Performance

by K. Buck and V. Zimpfer-Jost

Edited January 20, 2014 by iChris

[avbug]

7 dbz isn't much in a high noise environment. Anything that doesn't provide at least 25 dbz isn't doing enough.

 

ANR helps communication, but gives the illusion of hearing protection, and only does it in a narrow range.

[aeroscout]

I have a bose headset, but it was a ship's power version. There is an adapter that allows connection to single prong receptacles.

[rickferrin]

ANR has been around since the late 1980's. I think that's enough of a beta test. I have a BOSE X for every seat in my fix wing's (8) and two A-20's for my Rotorway. I've never tried any other ANR's...I'm certain they are great products as well. One thing that sold me on Bose, is their extraordinary customer service. When I have an issue with any of their products, they ship a replacement to me (next day air) at their cost.

 

I concur that none of them are too quiet that you can't hear what's going on. Indeed, I tend to hear more sounds.

Rick Ferrin

[avbug]

You can't hear more sounds, because the ANR headsets amplify nothing.

 

ANR makes the noise environment appear quieter by providing a combination of white noise and phase-cancelling sound in a narrow frequency range. You become a little more aware of low frequency sounds.

 

The headsets do very little to protect hearing, and may actually lead to hearing loss, especially by giving the illusion of protecting hearing in the first place. ANR headsets make it seem quieter. It's not.

 

I own several bose headsets. They make communication clearer and easier to understand. They've worked well for me in all kinds of climates and a number of different aircraft. They even held up well in some abusive environments in the middle east, as well as the cold of Siberia, and other locations that subjected the headsets or components to various extremes.

 

I don't use ANR in my helmet.

[palmfish]

Sound is nothing more than a pressure wave. Your eardrum feels the waves and sends a signal to the brain based on the frequency of the waves - high frequency = high pitch; low frequency = low pitch.

 

A noise cancelling headset creates an out of phase duplicate of an incoming wave, thus cancelling the wave, ie: the wave no longer exists. No wave = no sound. Period.

 

The limitation of ANR headsets is that they can only cancel lower frequency sounds, so higher frequency sounds must still be attenuated passively through traditional means (insulation). The good news is that high frequency sounds are much more easily attenuated by insulation than low frequency sounds (because the length of the wave is shorter), so its a win-win situation.

 

There are other variables (masking, bone conduction, etc.), but the basic physics is indisputable.

[Nearly Retired]

HUMOROUS CHEAP SHOT ALERT!! (Don't say I didn't warn you.)

 

Palmfish:

There are other variables (masking, bone conduction, etc.), but the basic physics is indisputable.

 

 

Indisputable? To Avbug?? *NOTHING* is indisputable to Avbug! Hey Avbug, the sky is blue.

 

Damn. Wasn't as funny as it sounded in my head before I wrote it. Sorry. I take it back. If only I could delete this post so that it never existed... Damn.