MARCH 2020 T3 59Noise cancelling headphones
cience is no stranger to
noise cancelling. Dr Paul
Lueg submitted his first
patent for wave-
cancelling technology way back in
1933, designing a system that could
be used to reduce vibrations in
loudspeakers; the theory was sound,
but the technology of the time did
not allow for the equipment to be
made. In the ’50s and ’60s, Dr
Laurence Fogel continued similar
research and issued patents for the
first viable devices, designed to
cancel the potentially harmful
frequencies of helicopter cockpits.
This time the tech was transferred
from speakers to ear directly, using
earphones to reduce the risk of more
damaging audio feedback.
Fogel, though considered the
inventor of active noise cancellation,
was not alone. Around the same
time the US Air Force was working
on a project to protect air crews’
hearing, culminating with the
design and testing of an active noise
cancelling project of its own. PD
Wheeler’s design was the first toescape the lab, seeing its first
experimental use in the then-new
(and extremely loud) Hercules
transporter. The tech focused on
attenuating low frequencies, since
the enclosed nature of a flight
helmet already deflected a majority
of high-pitched sounds. And it
worked, slashing 18dB of noise from
its intended range.FLIGHT OF FANCY
These are the seeds, but we need to
move further along the timeline to
really see ANC come of age. The story
goes that Amar Bose, irritated by the
inadequate headphones he was
offered on a 1978 international flight,
decided he could do better. Pulling
out a pen and paper, he sketched out
his own noise cancelling design
right there. Bose, an inventor known
for flashes of inspiration (“These
innovations are not the result of
rational thought; it’s an intuitive
idea,” he told Popular Science in
2004) had already popularised active
equalisation in the company’s
directional speakers. Bose’s ANCdesign – more practical, affordable
and effective than previous attempts- soon made itself comfortable in
cockpits the world over. The tech
accompanied Dick Rutan and Jeana
Yeager on the first round-the-world
flight in 1986. Still, technology took
its time to catch up; it was not until
the early 2000s, over 20 years after
that hasty in-flight sketch, that Bose
brought ANC to the consumer.
Now look at it: noise cancelling is
very big news. Miniaturisation,
innovation and refinement means
we’re in a new, more peaceful world.
And everyone’s at it. Bose’s foothold
has been eroded by countless other
companies. ANC is now not so much
a case of technological advancement
but of finding the right finely-tuned
algorithm. The right combination of
microphone, driver and software.
There might be tiny variations
between different implementations,
but the principle of ANC stays the
same whatever kit you buy. Now,
here comes the science: sound is a
waveform, travelling through air
with peaks and troughs of
S
Words: Alex Cox Photography: Neil GodwinActive noise cancelling enables you to block out the world and
melt into your tunes. It feels like magic, but how does it really
work? And what should you look for when buying a pair?
Noise
cancelling
headphones
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