Some time ago light aircraft crashed due to an engine failure. In the report the AAIB mentioned that the the four occupants were wearing ANR headsets and queried the possible masking of unusual noises by the headsets.
Without wanting to slag off the AAIB, but knowing the general mood in this country (UK) towards anything that's even remotely new (e.g. GPS.....), I'd take that statement with a BIG grain of salt.
That said, the engine does sound different with ANR on. I doubt very much that they could mask any noise leading to a failure, unless this is the very first flight of the pilot with ANR, IOW he's not yet used to the different aural environment. Trotting this out as argument against ANR makes about a much sense as claiming GPS is bad for navigation
But what about the inaudible spectrum? The Bose-X makes a lousy PNR headset so does it effectively filter out all the inaudible noises too? And is this filtering good enough to prevent hearing damage?
Good point, have been wondering that myself. Has anyone ever done any research into this? On the most basic level, ANR (Bose or otherwise) should protect your hearing by the simple fact that you don't have to have the volume up as high as in an PNR headset. The inaudible frequencies however....
In any case, I am very happy to fly with Bose-Xs for all the various reasons that have already been enumerated by others here.