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Installing
the MicMuff® Microphone Cover
(click on photo) |
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| The
MicMuff® Microphone Cover reduces
the noise level to less than 97dB, enabling a noise canceling
mic
to do
its job. |
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Above
97dB,
a mic without a MicMuff® Microphone
Cover resonates, fails to cancel
noise, and transmits and creates its own noise! |
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| The MicMuff® Microphone
Cover creates a chamber around the mic with limited
access for cockpit noise to enter the mic cartridges. |
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| Make
sure ALL headsets installed on your intercom have the MicMuff® Microphone
Cover! |
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| See MicMuff® Microphone
Cover Product Listing for mic photos to help you know
what to order. |
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| MicMuff® Microphone
Cover For
Amplified Dynamic Mic |
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| MicMuff® Microphone
Cover
Microphone For Electret Type Mic |
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| MicMuff® Microphone
Cover For Military Dynamic (M-87) Mic |
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PAINLESS
AND QUIETER
AVIATION HEADSET UPGRADES |
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Upgrade
includes SoftTop® Headset Cushion, SoftSeal® Ear
Cushions,
SoftSkin® Ear Seal Covers, HushKit® Passive
Ear Cup Noise Attenuation Kit,
and MicMuff® Microphone
Cover |
Why
Do I Have Such A Hard Time
Communicating On The Radio And Intercom
In A Noisy Airplane? |
Q
Why do I need a MicMuff® Microphone Cover in
a noisy airplane?
A Good
question! The short answer is that in a noisy airplane, a
MicMuff®
Microphone Cover enables a noise canceling mic to do its
job. But here’s
the complete explanation.
Aviation microphones are noise canceling
mics, built with two microphone cartridges aligned back to
back with a common output membrane. Look at your headset mic.
It has openings for sound to enter on both the front and back
of the microphone body.
Cockpit noise enters both sides of the mic
and cancels itself at the output membrane because this membrane
must resonate to put out a signal. By allowing the same sound
to enter both sides of the mic, the microphone cancels the
cockpit noise effectively. When you speak into the mic, your
voice mostly enters one side of the mic, causing membrane
to resonate, which creates the output signal (your voice)
without much of the ambient noise (cockpit sound). The output
signal-to-noise ratio (your voice vs. cockpit noise) is quite
good.
This technology works well until the ambient noise
level exceeds 97dB of sound pressure. This sound pressure
level is exceeded easily by the noise of a large engine, insufficient
sound insulation, an open cockpit, or an open ventilator,
doors or windows.
When the cockpit noise entering the microphone
exceeds 97dB, it causes the membrane to resonate harmonically
to the cockpit noise.This resonation makes a noise that sounds
like the "shhhh" of wind. The harmonically vibrating
membrane creates this noise, much like drawing your finger
over a phonograph needle (remember those?) creates a "shhhh"
noise.
Unfortunately, when the mic resonates,
it (1) fails to cancel cockpit noise, (2) transmits the noise,
and (3) creates additional noise! Your voice is lost in this
chaos. The signal (voice) to noise (other sound) ratio is
now reversed — there’s more noise than signal.
Q How does the MicMuff® Microphone
Cover fix this?
A The MicMuff® Microphone
Cover is a two-part device. The first part is an ordinary
foam sleeve
placed over the mic. You probably have something similar
on
your mic now. These sleeves are commonly called "wind
screens." They are not wind screens; they allow wind
to pass right through. The foam sleeve is really an "anti-sibilant"
which is meant to reduce the "sssss" and popping
sounds caused by pronouncing "S" or "P"
when speaking into the microphone. Oregon Aero uses the foam
to produce a chamber around the mic.
The second component of our MicMuff® Microphone
Cover is a solid leatherette sleeve with two small holes and an
elastic cord to fasten it onto the mic. This is pulled over
the foam sleeve and the two small holes are aligned with the
front and back openings on the mic. This combination creates
a small chamber around the mic with limited access for cockpit
noise to enter the mic cartridges. What is created is an acoustic
baffle around the mic which reduces the noise level at the
mic to less than 97dB. This allows the noise canceling mic
to do the job it was designed to do.
Q Will my voice go
through this small hole?
A Yes, easily.
Look at your cell phone mic opening; it’s probably smaller
than the head of a pin.
Q Will I need more
than one MicMuff® Microphone
Cover if
I have more than one headset?
A Probably. Most
intercoms make all the headset mics hot at the same time so
any mic without a MicMuff® Microphone
Cover will create noise in the whole
system. Like a bucket with two holes, plug one hole and the
other still leaks; you must plug both holes. Make sure all
headsets installed on the intercom have the MicMuff® Microphone
Cover.
Q Will the MicMuff® Microphone
Cover fit all microphones?
A Aviation mics come
primarily in three types. The small "Electret" type
uses a #90015 MicMuff® Microphone
Cover, the larger "Dynamic"
mic uses a #90010 MicMuff® Microphone
Cover, and the "M-87 Military"
mic uses a #90020 MicMuff® Microphone Cover.. |
Oregon
Aero founder and president Mike Dennis sometimes creates drawings
to explain concepts and how products work. We think these
drawing make the point well, so we’re sharing them with
you.
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| Below
97dB, cockpit noise enters both sides of the mic
and cancels itself at the output membrane of the
mic. Above 97dB, the microphone no longer cancels
the noise. |
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| Most
of the voice enters one side of a noise canceling
mic. Below 97dB, no problem. Above 97dB, the mic
not only doesn’t cancel the noise, it creates
and transmits additional noise. Your voice gets
lost in the chaos. |
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New
Radios? No, New MicMuff® Covers!
A
civilian pilot tested the Oregon Aero® MicMuff® Microphone
Cover in a Cessna 182 hauling jumpers, with the door
removed and no
aircraft insulation. On the pilot’s first transmission
to approach control with the MicMuff® Microphone
Cover on his headset
mic, the controller asked, "Did you guys get new
radios or something?"
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Aero-News.Net
Shows Oregon Aero
MicMuff®
Microphone Cover,
Headset Upgrade
 Mike
Gain of Aero-News.Net mentions the Oregon
Aero® MicMuff® Microphone
Cover and
shows the components of the Oregon Aero® Headset
Upgrade in his website aviation column.
"In our experience, some of the best
leather goods…are from Oregon Aero. The….microphone
bootie slides over the boom and eliminates much of the wind
noise, and improves the transfer of speech energy,"
says Gain.
Thanks for the voice of support, Mike!
|
How
To Install
The MicMuff® Microphone Cover
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| Slip
the foam sleeve over the microphone. This produces
a chamber around the mic. |
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| Place
the leatherette cover over the foam sleeve, with
the two small holes aligned with the front and
back openings on the mic. |
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| Remove
microphone screw that holds the boom. |
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| Pull
the MicMuff® Cover over the mounting bosses
and clamp the mic boom directly onto the MicMuff® Cover. |
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| Use
the mounting screw to pierce a hole through the
MicMuff® Cover and reinstall the screw, securing
the MicMuff® Cover. |
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| Tie
the elastic cord provided with the MicMuff® Cover into a square knot. |
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| Using
a needle nose plier, tuck the surplus elastic
cord inside the MicMuff® Cover.
Do not cut off the extra cord! |
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| The MicMuff® Cover
Microphone Cover is installed. Now everyone will
understand you better! |
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