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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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| "My
helmet is now the most comfortable it has ever been…in
35 years! The microphone ‘mufflers’ worked wonders.
We are able to optimize VOX operation on eight headsets in a
short period of time. No adjustments in VOX gain were required
when going from oxygen masks to headset booms." —
W.B., chief test pilot (This test was done in a C-130A
aircraft doing air drops with the ramp down.) |
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| Jim
Vanek of Sport Copter uses an Oregon Aero upgraded helmet.
The
more ambient noise in the cockpit, the more dramatic the improvement
in radio and intercom communication with the Oregon
Aero® MicMuff® Microphone Cover. |
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| People
will understand YOU better! |
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| You’ll
understand others better. |
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Oregon
Aero® Aviation Helmet Upgrades
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| MicMuff® Microphone Covers |
GSA
Schedule #GS-07F-5489R
| The MicMuff® Microphone Cover lets a noise canceling mic do its
job above 97dB. Eliminates ambient cockpit noise and noise
from
radios
and
intercom.
The noisier the cockpit (warbirds, open cockpit, large engine
aircraft), the more dramatic the improvement in noise reduction
and clarity. See Q&A for complete
information. MicMuff® Microphone Cover must be used on all
helmets installed in the communications system. Soft, washable
leatherette
cover
over foam sleeve creates chamber around mic. Cockpit noise
has limited access to mic cartridges, but voice enters
easily through
holes in leatherette cover. Doesn’t blow away. |
MicMuff® Microphone Cover For Amplified Dynamic mic #90010
(mics shown right) |
MicMuff® Microphone Cover For Electret type mic #90015
(mics shown right) |
MicMuff® Microphone Cover
For Military Dynamic (M-87) Mic
#90020
NSN 5965-01-387-8700
(mic
shown right) |
Read what our Satisfied
Customers are saying!
Why
Do I Have Such A Hard Time Communicating
On The Radio And Intercom
In A Noisy Airplane? |
| How
the MicMuff® Microphone Cover Works |
|
 BACK TO BENEFITS
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 helmet 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. An acoustic baffle is created 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
helmet?
A
Probably. Most intercoms make all the helmet 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 helmets 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 #90015MicMuff® Microphone
Cover, the larger "Dynamic"
mic uses a #90010 MicMuff® Microphone
Cover, and the "M-87 Military"
mic uses a #90020 MicMuff® Microphone Cover. |
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. For other styles of mic booms,
skip to #6. |
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| Remove
microphone screw that holds the boom. |
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| Pull
the MicMuff® Microphone
Cover over the mounting bosses and clamp the
mic boom directly onto the
MicMuff® Microphone
Cover. |
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| Use
the mounting screw to pierce a hole through the
MicMuff® Microphone Cover and reinstall the screw,
securing the Cover. |
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| Tie
the elastic cord provided with the MicMuff® Microhone
Cover into a square knot. |
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| Using
a needle nose plier, tuck the surplus elastic
cord
inside the MicMuff® Microphone Cover. Do not cut
off the extra cord! |
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| MicMuff® Microphone Cover is installed. Now everyone will
understand you better! |
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