ANR Headsets real and apparent attenuation question?
I've copied this over from the Medical and Health section (no responses) and would be interested in people's opinions. It seems to be taken for granted that some headsets protect your hearing when maybe they don't.
I've been researching buying a new headset recently and was deciding whether to go for ANR or not. There are hundreds of posts about the topic and it is clear that the general consensus is that if you have the money to spend, ANR is well worth having.
The most popular ANR headset seems to be the Bose Aviation X, with the main criticism being that it has poor passive attenuation (ie. provides little hearing protection with the ANR switched off).
Most dismiss this as not being a problem as it's a simple case of making sure the batteries don't run out. They also point out that although the Bose X is very expensive it's worth getting the best when the alternative is permanent noise induced hearing loss.
So I did a bit of Google work to find out more about ANR and I have found out that ANR technology only really works for lower frequencies and provides no protection for the higher frequencies (that are less audible to the human ear but are still damaging). It seems good ANR also needs good passive attenuation to block the higher frequencies.
Does this mean that headsets with good active (ANR) attenuation but poor passive attenuation, like the Bose X, should not be used in a lot of general aviation aircraft as they will result in the user suffering hearing loss?
If so Bose and others manufacturers should clearly warn users of the danger and make it clear which aircraft categories they are effective in. General aviation pilots might then know to choose ANR headsets that also offer high passive attenuation.