Helmet query
Gents
I am placing an order for an MSA Gallet 250 helmet that is offered with multiple configs, i.e. Bose, Lightspeed, DC, No ANR etc. Any feedback from the industry ref performance? I used both Bose and Lightspeed headsets stand-alone in a B412 previously and the Lightspeed blocked out the MR Low RPM horn. It also created feedback if the opposite pilots window was open. The Bose did not block out the Low NR horn but also created feedback if the opposite pilots window was open. has anyone experienced this utilizing both configs in a helmet? Thanks D |
If you have a good system (either in the helicopter, or in the headset), it should give you the option to modify the sensitivity of the "hot mike"-that should take care of the ambient noise issue.
I personally do not believe in the benefits of an ANR. To me, passive noise reduction is the way forward. I have been using custom molded ear plugs from the beginning under my helmets and headsets. 25 years and over 8000 hours later, my hearing is still excellent... |
Originally Posted by hueyracer
(Post 10823455)
I personally do not believe in the benefits of an ANR.
To me, passive noise reduction is the way forward. I have been using custom molded ear plugs from the beginning under my helmets and headsets. 1. Passive headset alone (assumes a high quality headset) 2. Earplugs alone (assumes a high quality, well fitted earplug) 3. ANR headset (assumes a high performance brand, i.e. Bose, Lightspeed, DC) 4. Passive headset with earplugs underneath Not sure about ANR with plugs underneath. Current ANR engineering assumes an open ear canal. Has anyone tried that? Make no mistake, there are blurry lines between all of those choices. Headsets, both passive and ANR, have better performance at low frequencies, earplugs at higher frequencies. Depending on your current state of hearing loss, the spectral content of the noise, and the psycho-acoustics associated with what types of noise bother you the most, your mileage may vary by quite a bit. At the end of the day it's a trade off between performance, convenience, comfort and cost. Personally I bounce between options 2 and 3 listed above. On hot days I prefer to err on the side of light weight and thermal comfort (Clarity Aloft) vs. convenience, irritated ear canals, and ultimate noise attenuation (DC ONE-X). But I'm flying without a helmet and flying relatively quiet Robinson products. If I was in noisier territory, or required/desired to wear a helmet, CEPs under helmet muffs would likely be my choice. Here's an interesting article on how ANR is quite obviously just another layer in the arsenal. |
Originally Posted by aa777888
(Post 10823600)
ANR is not a bad thing. ANR is primarily for folks who don't want to wear muffs and plugs together. It's all part of a continuum of noise reduction options. From least effective to most effective:
1. Passive headset alone (assumes a high quality headset) 2. Earplugs alone (assumes a high quality, well fitted earplug) 3. ANR headset (assumes a high performance brand, i.e. Bose, Lightspeed, DC) 4. Passive headset with earplugs underneath Not sure about ANR with plugs underneath. Current ANR engineering assumes an open ear canal. Has anyone tried that? Make no mistake, there are blurry lines between all of those choices. Headsets, both passive and ANR, have better performance at low frequencies, earplugs at higher frequencies. Depending on your current state of hearing loss, the spectral content of the noise, and the psycho-acoustics associated with what types of noise bother you the most, your mileage may vary by quite a bit. At the end of the day it's a trade off between performance, convenience, comfort and cost. Personally I bounce between options 2 and 3 listed above. On hot days I prefer to err on the side of light weight and thermal comfort (Clarity Aloft) vs. convenience, irritated ear canals, and ultimate noise attenuation (DC ONE-X). But I'm flying without a helmet and flying relatively quiet Robinson products. If I was in noisier territory, or required/desired to wear a helmet, CEPs under helmet muffs would likely be my choice. Here's an interesting article on how ANR is quite obviously just another layer in the arsenal. If you fly piston however, ANR is really good at suppressing the low frequency drone of the piston engine. Passive headsets, and helmets with merely passive noise attenuation won’t get rid of that engine noise. ANR headsets often don’t work at all with ‘doors open’. I think this is what the OP describes with “copilot window open” etc. The ANR system gets confused by the wind buffeting, and creates an unbearable artefact noise. I personally had this with the Bose A20. I would assume that this is lesser of a problem when the ANR headset speakers are embedded in a helmet, but can’t speak from experience here. |
Originally Posted by Hot and Hi
(Post 10823639)
It also largely depends whether you fly piston or turbines.
And rumors Are that the anti-noise created by the ANR headset creates long-term damage to the ear. ANR headsets often don’t work at all with ‘doors open’. I think this is what the OP describes with “copilot window open” etc. The ANR system gets confused by the wind buffeting, and creates an unbearable artefact noise. I personally had this with the Bose A20. I would assume that this is lesser of a problem when the ANR headset speakers are embedded in a helmet, but can’t speak from experience here. Things do get really weird, often unusable even, when you cup or cover the external noise sensing microphone with your hand. Not being a helmet user I wonder how the ANR helmet installations handle the placement of those microphones? That by itself may be the source of some of the reported issues. |
Originally Posted by Hot and Hi
(Post 10823639)
ANR headsets often don’t work at all with ‘doors open’. I think this is what the OP describes with “copilot window open” etc. The ANR system gets confused by the wind buffeting, and creates an unbearable artefact
noise. I personally had this with the Bose A20. I would assume that this is lesser of a problem when the ANR headset speakers are embedded in a helmet, but can’t speak from experience here. |
Originally Posted by aa777888
(Post 10823681)
Things do get really weird, often unusable even, when you cup or cover the external noise sensing microphone with your hand. Not being a helmet user I wonder how the ANR helmet installations handle the placement of those microphones? That by itself may be the source of some of the reported issues.
|
There’s no chance an ANR headset designed to work unobstructed will work, unmodified, within a helmet.
alarm buzzers aren’t usually within a frequency/decibel range that should be sufficiently attenuated to become inaudible. |
Never had a problem hearing the Robinson horn with either Bose or DC ANR. Never had a chance to try the Lightspeed stuff.
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Honestly there’s no substitute for CEP or equivalent when flying 412’s or utility work requiring doors off etc
|
Originally Posted by aa777888
(Post 10823681)
Things do get really weird, often unusable even, when you cup or cover the external noise sensing microphone with your hand. Not being a helmet user I wonder how the ANR helmet installations handle the placement of those microphones? That by itself may be the source of some of the reported issues.
The design highlighted the need for properly fitted helmets. Hitherto, many aircrew had chosen to have a slightly oversized helmet, for comfort. But the airgap, especially when wearing spectacles, caused feedback; exacerbated by the acoustic chamber being smaller due to the PCB. The solution included a new design of earshell padding, and made to measure helmet fitting. (Which should be the norm anyway). The company had a laser mapping system, which was simply fed to the machine that formed the helmet shell. Added a few quid to the cost, but worth every penny. Edited to add image. There's a small rectangular thing sitting at 45 degrees to the tels transducer. That's the upper ANR transducer. This is the prototype, before the low profile one was fitted. https://i.ibb.co/4g8bptK/anr-helmet-2.jpg https://i.ibb.co/CwhKFSz/anr-2.jpg |
I am currently running Bose A20 in an Evo helmet and the results are variable. Brilliant helmet, absolutely love it, and when the ANR goes good life is great. However, depending on the aircraft, and flight condition the buffeting from the ANR can drive you insane...
different helicopters cause different buffeting at different times. One Jet Ranger is fine with doors on, but hell with door off. Another Jet Ranger is really bad with doors on, but actually quite good with doors off.... The hueys all behave differently, one fully enclosed with a bubble window is beautiful no buffeting so really good. Another one is ok with the window in, and no good with window out, another is the opposite good with the window out and crap with the window in. I wish i could figure it out, but i just swap between ANR and CEP helmet, depending upon what helicopter I'm going to fly, and what I'm doing. |
Thanks for all the info. I’m thinking safest bet is CEP.
D |
Originally Posted by donner89
(Post 10824171)
Thanks for all the info. I’m thinking safest bet is CEP.
D https://www.pprune.org/rotorheads/621795-anr.html https://www.pprune.org/rotorheads/289573-anr-headsets.html https://www.pprune.org/rotorheads/110753-helmets-should-you.html https://www.pprune.org/rotorheads/364122-cep-communication-ear-protection.html |
Originally Posted by SuperF
(Post 10824151)
I wish i could figure it out, but i just swap between ANR and CEP helmet, depending upon what helicopter I'm going to fly, and what I'm doing.
But to your problem SuperF, depending on what type of ANR it is, it may be unrealistic to expect it to work in an aircraft it is not designed for. The Sea King ones were good for ASW and AEW variants, but not for the Mk4. Purely by coincidence, they worked in Sea Harrier. They were hopeless in Lynx, not too bad in Merlin but only for rear crew. Just minor component value changes to target the damaging frequencies in different aircraft, and let the frequencies you need to hear through. At the most cheap and cheerful level, you can be sold a broadband system such as that used in the back of armoured vehicles. They don't have to worry about what you need to hear, and blot out most noise. The one above is the analog system, designed to meet the then 85dBA requirement. (Around 83 achieved). You needed a noise survey in each aircraft type/mark, and from that a variant of the PCB was developed. You either had a second helmet, or spent an hour changing the capsules. (And there has to be the same power source/connector). In the military, ANR presents a further problem - the helmet is no longer just an Aircrew Equipment Assy, it is a Comms System LRU, as it is aircraft powered and sits inside the TEMPEST boundary. And the associated curly leads were far more expensive that the ANR helmet. Concurrently, a Digital ANR was developed to meet the new 75dBA requirement, and by 2000 had achieved around 71dBA. ISD was due 2001, but I'm not sure what happened as I was gone by then. That was programmable, so if you wanted to fly a different type one day, you simply plugged the helmet into a workstation and blew the EPROM for that aircraft. The next development milestone was adaptive ANR, which aimed to negate all that faff. I know it was successful - the same team at Farnborough did it - but don't know how widely it is used. The answer to your problem is not straight forward, but hopefully I've given a few pointers on what to ask of your supplier. I won't comment on Bose and ANR! |
Originally Posted by donner89
(Post 10824171)
Thanks for all the info. I’m thinking safest bet is CEP.
D Another key to having good ANR performance with wind in the cabin is a very solid ear cup seal to your head. Make sure to spend time with the padding to ensure the seal isn't broken when you turn or tilt your head. |
Originally Posted by donner89
(Post 10824171)
Thanks for all the info. I’m thinking safest bet is CEP.
D |
Originally Posted by havick
(Post 10824909)
If you want bomb proof CEP with the best noise reduction, look at getting custom moulded ear plugs with the HELO CHAIS. It uses the same CEP plug.
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