There is one crucial point that seems to be being missed in this discussion.
We have flown with ANR headsets for the last two years. Ours are not very
sophisticated as they are one of the very first ones made (made by Skyforce)
but the |ANR does offer a very good degree of noise cancellation and it is
true that this is mainly "bass" frequency".
We were thinking of replacing these sets for a more expensive version (eg:
Sennheiser or Pilot DNC) till my wife suggested that the noise might not be
coming from through the headset shells but might be amplified noise through
the microphone. Sure enough, when the intercom was switched off, the headset
noise was reduced dramatically. We have since conducted a flight where the
intercom was kept off for long periods and this was much more relaxing.
It seems possible that although advanced ANR designs may cancel out some of
this microphone induced noise it would be better if it could be prevented
---From being picked up in the first place. My previous headset was a Peltor
(non ANR) and this used a voice activated microphone - I recall that again
with the mic off there was much less noise.
Before discarding our present headsets we are going to try and see if there
is any way of shielding the mikes from the ambient cockpit noise.
Has anybody tried to do this (or even used a throat mic).
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