Cockpit noise
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Cockpit noise
Hi all,
Does anyone know the average noise level in dB's of a PA28, C150/172 cockpit when the engine is running at full power?
Exposed to this kind of noise each day may harm your hearing therefore does the Passive headset with 24dB protection offer enough protection for your hearing in this environment?
Look forward to your reply's,
Many thanks.
Does anyone know the average noise level in dB's of a PA28, C150/172 cockpit when the engine is running at full power?
Exposed to this kind of noise each day may harm your hearing therefore does the Passive headset with 24dB protection offer enough protection for your hearing in this environment?
Look forward to your reply's,
Many thanks.
Okay, I'd better try to be a little less flippant this time.
As I understand it (and, as always, I am willing to be corrected)passive noise reduction is merely the fact that you've got a great big padded headset between your delicate little ears and the big old noisy machine.
Active noise reduction means that the clever old headset listens to the noise that's managed to get in and then creates more noise but this is, if you like, inverted noise so when you add together the original noise and the new inverted noise you actually get less noise.
That's me, trying not to be flippant. I'm sure others can add to that explanation but, as anyone who ever tried to teach me physics will testify, that's about as far as my brain goes.
Bad Noise + Good Noise = Less Noise
As I understand it (and, as always, I am willing to be corrected)passive noise reduction is merely the fact that you've got a great big padded headset between your delicate little ears and the big old noisy machine.
Active noise reduction means that the clever old headset listens to the noise that's managed to get in and then creates more noise but this is, if you like, inverted noise so when you add together the original noise and the new inverted noise you actually get less noise.
That's me, trying not to be flippant. I'm sure others can add to that explanation but, as anyone who ever tried to teach me physics will testify, that's about as far as my brain goes.
Bad Noise + Good Noise = Less Noise
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An ANR headset has a mike inside each earcup, and an amplifier circuit which drives the speakers in antiphase.
The cancellation works only over a relatively narrow frequency band - not least because the volume of air involved is too great to make it work over a wide band.
I'd be careful about attenuation claims in adverts though.
The cancellation works only over a relatively narrow frequency band - not least because the volume of air involved is too great to make it work over a wide band.
I'd be careful about attenuation claims in adverts though.
Now you see - ANTIPHASE - why don't I know words like that? It means the same as my "inverted noise" but sounds so much better.
It is by far cheaper to go deaf early - try motorcyling, rock concerts, operating heavy machinery and standing next to helicopters.
That can work across quite large frequency bands and you don't need to do physics.
It is by far cheaper to go deaf early - try motorcyling, rock concerts, operating heavy machinery and standing next to helicopters.
That can work across quite large frequency bands and you don't need to do physics.
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I have seen these figures somewhere. Perhaps a chat to headset services will give some accurate figures but I thought it was around 100 decibels at full power.
24db of attenuation brings it down to 76 which is a bit like the sound of a loud television (I think). 60 Db is a wisper.
Sound is not linear. It doubles every 3 Db.
That said most pilots who have flown for a long time have suffered hearing loss and ringing due to ear damage. These figures make a good argument for spending £700 on a headset now. Presumably once you have lost your hearing you will happily pay £700 to get it back rather than wear a hearing aid. The active headsets boast an additional 15 ish db reduction.
24db of attenuation brings it down to 76 which is a bit like the sound of a loud television (I think). 60 Db is a wisper.
Sound is not linear. It doubles every 3 Db.
That said most pilots who have flown for a long time have suffered hearing loss and ringing due to ear damage. These figures make a good argument for spending £700 on a headset now. Presumably once you have lost your hearing you will happily pay £700 to get it back rather than wear a hearing aid. The active headsets boast an additional 15 ish db reduction.
I got hold of a quality pair of passives from ebay for £100 and I find the cockpit noise very low. Only problem is sunglasses break the seal between the gel cups and your head which lets a lot of noise in. Presumably ANR headsets suffer less from this?
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No, ANR headset suffer from that too. They like a good seal to work properly.
There is a seperate thread here about that a week or two old.
I found the "stop gaps" help to largly solve that problem.
dp
There is a seperate thread here about that a week or two old.
I found the "stop gaps" help to largly solve that problem.
dp
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They are little pieces of foam that fit around the arms of your glasses. They are supposed to improve the seal. Didn't work for me.
By the way I think the ANR headsets need a good seal more than passive ones do.
By the way I think the ANR headsets need a good seal more than passive ones do.
