How to drown out a helicopter
Picture the scene… London, summer 2018, it’s hot, so hot that British people have been able to take showers straight off the cold tap in their homes.
Day after day of 30+ degree Celsius heat has taken its toll on a public who quite frankly have had enough of barbeques and would like a nice hot bowl of soup and some rain to complain about thank you very much.
Like many of us, I have been working with my windows open in an attempt to cool down.
Now then, for most people, this technique works just fine. But if you, like me, live close to Battersea’s London Heliport, then it can be quite noisy when the various dignitaries and glitterati decide to land or take off.
Here’s the problem.
London Heliport is arguably somewhat lax when it comes to stipulating exactly how close pilots are allowed to come to the buildings around the Battersea towpath.
Some pilots take a considerate outward loop well away from residents homes and make their approach and exit well out into the river.
Others though, presumably looking to either save fuel or provide a more thrilling ride for their passengers, skirt the edge of the buildings along London’s Clove Hitch Quay with a kind of devil-may-care swoop that really puts the wind up those us living just a few feet away.
I have personally taken it upon myself to go in and talk to the London Heliport manager (a Mr Simon Hutchins) and explained that some of the choppers come too close.
“Oh, it’s due to the wind on the day,” he told me… before offering me a look at the landing ‘apron’, which was all quite exciting if I am honest.
So… next tactic: send tweets to @LondonHeliport with images of the helicopters that fly too close? No use: “You are blocked from following @LondonHeliport” was the eventual report that comes back. I’m actually genuinely quite impressed i.e. nobody has ever blocked me on Twitter, so well done London Heliport, at least you’ve set one record.
Technology is the answer
As always with these things, technology provides the answer.
I got myself a set of Jabra Evolve 80 headphones with Active Noise Cancellation (ANC) technology.
These ‘cans’ are over the ear (as opposed to ‘on ear’) so they completely cover my poor lug-holes. Once I switch on the ANC function, it drowns out a good proportion of all background noise.
As Jabra notes, “You can switch on active noise-cancellation to virtually eliminate low-frequency sounds, such as the hum of air conditioning. Active noise-cancellation uses advanced microphones to monitor and counter ambient noise. All Jabra USB headsets and speakerphones work with all the most popular online voice call services. [The product] works straight out of the box with all leading UC systems and the 3.5 mm jack lets you connect to a PC, smartphone, tablet, or any other personal device.”
Is it enough to drown out a helicopter passing by my window 50 feet away?
With ANC switched on and Absolute Classic Rock playing, yes, for the most part.
How ANC works
Paradoxically, Active Noise Cancellation (ANC) technology was originally created for airplane pilots to improve their comfort on long flights.
As the Guardian notes here, “ANC works by using microphones to pick up low-frequency noise and neutralise it before it reaches the ear. The headset generates a sound that’s phase-inverted by 180 degrees to the unwanted noise, resulting in the two sounds cancelling each other out.”
Aircraft jet engines create somewhere between 75 to 80 dB of noise inside an aircraft cabin — and most ANC headphones including this Jabra unit generate what is known as ‘destructive interference’ ranges between 20 and 45 dB, so you’re never going to drown out a full helicopter effect really.
Plus also, ANC is more efficient against low-frequency sounds.
According to a Wikipedia, to prevent higher-frequency noise from reaching the ear, most noise-cancelling headphones depend on soundproofing.
“Higher-frequency sound has a shorter wavelength and cancelling this sound would require locating devices to detect and counteract it closer to the listener’s eardrum than is currently technically feasible or would require digital algorithms that would complicate the headphone’s electronics,” notes this post.
The fun part, well, for me, is that the Jabra headset I went for has a fancy swivel around microphone for webchats and calls – so I do look amusingly rather like a helicopter pilot sat at my desk writing this up.
The moral of this story is, if you live next to a heliport and it’s the hottest summer on record, then you had better get hold of some noise cancellation technology and you had better like 90s ‘grunge’, alternative rock and heavy metal.