Flight Training - October 2014 - 13
HOW IT WORKS
Active noise reduction
BY IAN J. TWOMBLY
No more shouting
HARD AS IT is for today's student pilots to believe, headsets are
a relatively new cockpit accessory. Most people learned to fly
by shouting and a system of rudimentary hand signals. Today
there are dozens of headsets to choose from, including many that
feature active noise reduction technology (ANR), which makes
flying more comfortable and considerably reduces fatigue.
Although the process seems simple, the technology involved
in making a good ANR headset is incredibly complex. Matt
Ruwe, the senior product manager for Bose aviation and
military headsets, says the company's A20 headset "senses the
sound, processes it, and cancels it" with an opposite frequency.
The A20 has two microphones in each ear cup, one on the
outside and one on the inside. Those microphones pick up the
ambient sound from each environment, and then a combination
of analog and digital circuits analyze it, and a speaker inside the
ear cup sends out a frequency that's on the opposite wavelength. In this case two sounds make it right.
According to Ruwe, ANR works well at low frequencies,
which primarily come from the drone of the engine. In fact,
he says, it would take a thick slab of lead to do an equivalent
job at stopping the sound. High frequencies are stopped easily
with the ear cup. It's what the industry terms passive noise
reduction.
The Bose A20 and its competitors do such an incredible job
of reducing noise that Ruwe says most of the focus has turned
to comfort and clarity. He said engineers at Bose work hard to
lighten the headset, and to try and make it fit a variety of head
shapes and sizes.
STEVE KARP
HOW TO PICK A HEADSET
Headset manufacturers love to list specifications of how much noise reduction their product has, the features it incorporates, or
how their build process is better. The only thing you need to know is how comfortable it is. If you're looking at a particular model,
borrow one from a friend or see if a seller has a demo program. Fit and comfort matter far more than a decibel rating, although that,
weight, and build quality are valid markers to determine value.
OCTOBER 2014 FLIGHT TRAINING
/ 13
Flight Training - October 2014
Table of Contents for the Digital Edition of Flight Training - October 2014
Contents
Flight Training - October 2014 - Cover1
Flight Training - October 2014 - Cover2
Flight Training - October 2014 - Contents
Flight Training - October 2014 - 2
Flight Training - October 2014 - 3
Flight Training - October 2014 - 4
Flight Training - October 2014 - 5
Flight Training - October 2014 - 6
Flight Training - October 2014 - 7
Flight Training - October 2014 - 8
Flight Training - October 2014 - 9
Flight Training - October 2014 - 10
Flight Training - October 2014 - 11
Flight Training - October 2014 - 12
Flight Training - October 2014 - 13
Flight Training - October 2014 - 14
Flight Training - October 2014 - 15
Flight Training - October 2014 - 16
Flight Training - October 2014 - 17
Flight Training - October 2014 - 18
Flight Training - October 2014 - 19
Flight Training - October 2014 - 20
Flight Training - October 2014 - 21
Flight Training - October 2014 - 22
Flight Training - October 2014 - 23
Flight Training - October 2014 - 24
Flight Training - October 2014 - 25
Flight Training - October 2014 - 26
Flight Training - October 2014 - 27
Flight Training - October 2014 - 28
Flight Training - October 2014 - 29
Flight Training - October 2014 - 30
Flight Training - October 2014 - 31
Flight Training - October 2014 - 32
Flight Training - October 2014 - 33
Flight Training - October 2014 - 34
Flight Training - October 2014 - 35
Flight Training - October 2014 - 36
Flight Training - October 2014 - 37
Flight Training - October 2014 - 38
Flight Training - October 2014 - 39
Flight Training - October 2014 - 40
Flight Training - October 2014 - 41
Flight Training - October 2014 - 42
Flight Training - October 2014 - 43
Flight Training - October 2014 - 44
Flight Training - October 2014 - 45
Flight Training - October 2014 - 46
Flight Training - October 2014 - 47
Flight Training - October 2014 - 48
Flight Training - October 2014 - 49
Flight Training - October 2014 - 50
Flight Training - October 2014 - 51
Flight Training - October 2014 - 52
Flight Training - October 2014 - 53
Flight Training - October 2014 - 54
Flight Training - October 2014 - 55
Flight Training - October 2014 - 56
Flight Training - October 2014 - Cover3
Flight Training - October 2014 - Cover4
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