All Quiet at 35,000 Feet

I had suspected that a recent flight, a puddle-jumper from Seattle to
Victoria, BC, might be a noisy one. Sure enough, at the end of the pilot’s
safety briefing, he offered me and my fellow travelers, little plastic bags of
earplugs.

I declined. I had my own. In my bag were a half-dozen sets of noise-canceling
headphones from four manufacturers. I had planned this short trip in a
four-passenger floatplane as the perfect test. If the headphones could silence a
deafening propeller engine, they should have no problem dulling the roar inside
the cabin of a conventional jet.

Medical
studies have shown that noise, especially low-frequency noise, causes fatigue.
You know the problem. Even after a relatively short two- or three-hour plane
trip, you arrive at your meeting or hotel feeling tired, and for no good reason.
In a week of flying, I found that any of the headsets I tested will eliminate
that issue.

Noise-canceling technology is not new. Pilots have used headsets like these–but
versions that cost up to $1,000–for years, even when they’re not at the
controls. I discovered the benefits six years ago when the first consumer model
appeared, a $150 headset from NCT Group. Back then, I thought the price was a
bit high for audio headphones. But the real problem was that the electronics
that create the noise-canceling signal were housed in a heavy, bulky box the
size of a pack of cigarettes, and they burned through a nine-volt battery every
couple of days.

That has changed over the past couple of years. There are now dozens of
models on the market, ranging from $40 to around $300. They’re powered by one
or two AAA batteries good for around 100 hours. I immediately discovered that
price has little to do with how well they work. True, my favorite is the most
expensive set, the $299 Bose QuietComfort model. But a close second is NCT’s
current pair, the $40 NoiseBuster Extreme. It’s noticeably less stylish–it
looks and feels cheap, in fact–and slightly less comfortable than the Bose
headphones. But it suppresses more low-frequency airplane noise than any of the
others.

I also looked at Sony’s MDR-NC20, and Panasonic’s RP-HC100. Both are big,
closed-back-style headphones with the control electronics, battery, and on-off
switch built into the right phone instead of a separate handheld unit. They fold
for travel, unlike the Bose and NCT models, but neither could match their level
of noise reduction. Depending on where you shop, the lightweight Panasonic
RP-HC70 does a better job reproducing music and, like my favorites, lets you
choose the level of noise suppression. If you don’t mind a headset where the
speakers fit inside your ear canals, then try Sony’s MDR-NC11, which goes for
$100 to $115 at Internet retailers.

A word about the technology, just so you know the answer when your airplane
seatmate asks. All of these headphones use tiny microphones mounted on or inside
the headset to pick up the ambient noise just before you hear it. They take that
signal, electronically create its exact opposite, and feed the opposing signal
to the headset’s speakers. The result is that the electronically generated
sound waves from the headset cancel out the noise around you before you can hear
it. What’s left is the audio signal that you’re plugged into, the airplane’s
audio system, say, or your own CD or MP3 player.

This technique only works for low-frequency sounds, though, which is why they’re
so good at scrubbing out aircraft noise.

They are as effective against other low-frequency noise as well–you’ll
find yourself grabbing them when you mow your lawn.

To test these gizmos against high-frequency noise, I booked the next leg of
my trip on a helicopter. They were pretty useless when confronted with the
high-pitched whine of the rotor’s gears directly above our heads. To get rid
of higher-frequency cabin noise, typically screaming infants, or overly chatty
pilots, you have to physically block it. For that, the closed-back Sony and
Panasonic models are good. The Bose, which completely surrounds your ear and
nestles against your head, is even better.

Be warned: You won’t be able to hear the flight attendant ask
whether you want chicken or fish. But that’s no great loss, is it?

BusinessWeek