In flight audio output from the
Enhanced Noise Reduction Intercom. Click to listen.
In flight audio from a voice operated intercom.
Click to listen.
The recorded audio is audio from the intercom output.
Depending on the passive or acoustic noise reduction quality of the headset,
some ambient noise will be heard through the ear cup. The recorded audio
is what is heard through the headphone's ear cup speaker.
*These audio clips work best with Internet Employer 5 or
later and versions of Netscape above 4.6.
Functional diagram displaying the difference between the Enhanced Noise
Reduction Technology and 30 year old Voice Operated technology
*Note: the microphone symbol on the input of the diagrams, is
actually the headset microphone, not a separate microphone.
Questions & Answers
What is Enhanced Noise Reduction ?
With a voice operated
intercom, wind and engine noise is heard when the headset's microphone audio path is open.
Depending on the intercom and headset microphone, the background sounds can be
quite annoying. With voice operated intercoms, you have to kick
start the audio path by speaking and then after stopping, the
microphone is open allowing background noise to be heard until the audio
path closes. This is the case with either manual or auto-squelch
systems.
ENRI eliminates what the open microphone hears and you the pilot don't want
to hear - that rushing wind sound and engine noise. Since the
microphones are open all the time with ENRI, there are no missed words or audio
drops between words, and no background noise, even while you
are talking.
What is the Difference between ENRI
and ANR headsets?
In an ANR headset, a small microphone in each ear cup shifts the sound 180 degrees out
of phase from the direct sound that the ear hears, canceling out the
noise and giving additional noise reduction to the acoustical reduction of
the ear cups. This ANR reduction works with a small band of the
audio spectrum, usually 30 hz to 400 hz. Above the ANR
band pass frequency, the headset is the basic Passive Headset.
The typical headset
microphone will pick up sounds ranging from 30 hz to 4000 hz, leaving
a broad noise range above 400hz, not canceled by ANR. With a
Voice Operated intercom, sounds about the 400hz audio range are passed to the intercom and
heard in both ANR and Passive headsets.
ENRI takes over where the ANR headsets leave off, canceling audio noise
across the 40hz to 4000hz that is picked up by the headset's microphone, which
includes wind noise and high pitch engine sound.
Will I hear additional noise reduction with
passive headsets?
ENRI will not increase noise reduction of acoustical or passive reduction
headsets.
Open Cockpit Aircraft
Open cockpit aircraft present the greatest challenge to eliminating
or reducing noise during communications. Because the ENRI circuit works
on noise levels, some cases, such as engines producing very high noise
levels during take off, may exceed the threshold of the circuit and will be
heard.
Wind blowing across the microphone may also create a beating noise that
will be heard.
In either case, it is recommended that wind muffs be added to the
microphones. The foam type will improve the communications in most
applications but in some extreme cases, a combination foam and leather muff
made by Oregon Aero greatly improves communications.
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