On 30 Aug 2006 12:10:35 -0700, "nrp" wrote:

Not all ANR headsets work on the same principle.

I understand that most of them are digital, in that they look for
repetitive noise & then use digital algorithims to s-l-o-w-l-y cancel
out the repetitive components of any noise signal. This has the
advantage that they can work to higher frequencies, but limited in that

But you don't need to have them work at higher frequencies and I
absolutely do not want them to work at higher frequencies. I can hear
the wind noise albeit weakly. I can hear the accessories on the
engine and I can hear voice through the set very well. Not too bad
even from some one beside me as the noise is only coming from one
direction and is not completely canceled by the ANR function.

they only work with repetitive (i. e. cyclic) signals. They are unable
to cancel random noise.

To me, those would be the ones to stay away from.
I see it as a case in simple is better.


Some (the Headsets Inc version and maybe others) are a broad band
analog bucking system. They do not cancel just a repetitive
excitation, but can also cancel most of any random noise sensed by the
internal microphone system. The disadvantage of this type is that it
can work only at frequencies below typically about 300 Hz. Above this,

These including my Telex work very well up through the voice
frequencies. Don't believe what you hear about 300 Hz. If this were
true I'd hear a lot of prop noise at full RPM and I don't. After all
the prop makes more noise than anything else on, or in the plane. They
work well up to around 3000 Hz. At least all I've tried have.

and they must rely on the passive noise rejection of the headset cups -
which is pretty good at high frequencies. It is low frequencies that
passive systems have the poorest atenuation.

Anyone else with more of the puzzle?
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com