Skip to main content

Active Noise-Canceling

In this episode - Active Noise-Canceling . . .

During a recent flight, with a baby wailing, I realized I had forgotten my noise-canceling headphones and wondered how they work. Have you noticed the constant background roar of jet engines during a flight? Probably not if someone was trying to comfort a squalling baby in front or behind you.

Anyway, noise reduction headphones, also known as Active Noise-Canceling (ANC) headphones, use advanced technology to reduce or eliminate unwanted ambient sounds. Using hardware and software components to counteract external noise and provide a more immersive listening experience and a quiet environment.

Here's a simplified overview of how noise-reduction headphones work:

  • Microphones: ANC headphones are equipped with one or more built-in microphones. These microphones capture the surrounding sounds and convert them into electrical signals.
  • Noise analysis: The electrical signals from the microphones are analyzed by the headphone's internal circuitry. The goal is to identify the frequency and amplitude of the ambient noise.
  • Reverse sound wave generation: Once the noise is analyzed, the ANC system generates a sound wave in the opposite phase to the ambient noise. This reverse sound wave is known as an anti-noise or anti-phase wave.
  • Combining sound waves: The anti-noise wave is combined with the original ambient noise wave. When the two waves meet, they interfere with each other in such a way that they cancel out or significantly reduce the overall sound level.
  • Output to the listener: The resulting sound, with reduced ambient noise, is output to the listener through the headphones' speakers. This allows the user to enjoy their audio content or eliminate the jet engine sounds, allowing them to sleep.

It's important to note that noise-canceling headphones work best for blocking constant, low-frequency sounds like engine noise, airplane cabin noise, or air conditioning hum. They may be less effective against sudden or irregular sounds, such as human voices or high-pitched noises. 

Additionally, the effectiveness and performance of noise-canceling headphones depend on the quality of the ANC technology, the number and placement of microphones, and the overall design. Although different manufacturers may use slightly different approaches to achieve noise reduction, most ANC headphones operate on similar principles.

So my next question was, “Who invented active noise-canceling (ANC) headphones?”

Active noise-canceling (ANC) technology for headphones was developed by a team of engineers led by Dr. Amar Bose, the founder of Bose Corporation. In the late 1970s, Dr. Bose was on a flight and noticed the significant amount of noise generated by the aircraft engines. This inspired him to explore ways to reduce unwanted noise and improve the audio experience for listeners.

Dr. Bose and his team conducted extensive research and experimentation to develop the first practical active noise-canceling headphones. They filed a patent application for their invention in 1978, which was later granted in 1986 (US Patent No. 4,545,982). The patented technology outlined uses multiple microphones, phase inversion, and electronic circuitry to cancel out ambient noise.

Bose Corporation introduced its first consumer ANC headphones, the Bose QuietComfort series, in 2000. These headphones gained popularity for significantly reducing background noise and providing a more immersive audio experience. Since then, ANC technology has become increasingly widespread, and many companies have developed versions of noise-canceling headphones based on the principles established by Dr. Bose and his team.

When flying, remember to pack your ANC headphones. As a side note, you can purchase headphones from vending machines after passing airport security if you forget yours.

I'm Patrick Ball; thanks for listening. See you in the next episode.

Labels:

Comments

Post a Comment

Most Popular of All Time

The Gopher Problem and the High Powered Solution

Vacationing in Maine this week, just a short drive down the coast from Freeport, it is hard not to think about the outsized impact one frustrated outdoorsman had on the gear we all use today. Bad equipment can ruin a perfectly good day on the water or the trail, but it takes a special kind of vision to turn cold feet into a century-old empire. This is the story of the company we now know as L.L.Bean, but more importantly, it is a masterclass in integrity, learning from failure, and standing behind your work. In 1912, Leon Leonwood Bean faced a persistent problem: returning from expeditions in the Maine woods with cold, wet feet. Instead of complaining, he got creative. He had a local shoemaker stitch waterproof rubber soles onto the flexible leather uppers of a hunting boot. He called it the Maine Hunting Shoe and mailed a flyer promising perfect satisfaction. Then reality arrived. Ninety of his first 100 pairs failed when the rubber separated from the leather. Not an effective product...
Post a Comment
Read more

On Becoming Real

Some things get better with wear: old shoes, old friendships, and old books. Especially old books. A new volume arrives with crisp corners and a spine that hasn’t yet learned to bend. An old one has been somewhere. It has traveled through time in the hands of people who may no longer be around to tell us what they found inside. The copy of The Velveteen Rabbit (first published in 1922) on my desk is one of those books. My friend Don Hanley gave it to me. This late-1950s Doubleday edition features William Nicholson’s original illustrations and cream paper boards softened by age. Worn corners, a split spine, and colored tabs mark passages worth revisiting. Don didn’t hand me a keepsake. He gave me homework. When we talked about the book recently, he pointed me straight to the nursery conversation between a young rabbit and an old Skin Horse. The rabbit had noticed the mechanical toys around him—the ones with internal gears, bright paint, and stick-out handles that seem terribly impressiv...
Post a Comment
Read more

A Dog, a Beer . . . and the Ghost of 1912

Whenever you step into an American cathedral of our National Pastime built before modern ergonomics, municipal zoning, or crowd-flow dynamics, an unspoken understanding forms, creating a welcoming, timeless atmosphere. You trade legroom, sensible corridors, and personal space for the privilege of communing with ghosts. Last week, Lori and I made our pilgrimage to Fenway Park to watch our Chicago Cubs take on the Boston Red Sox (a taut 0–2 contest that felt spiritually tied to their 1918 World Series meeting). Staying just across the Charles River at the Courtyard Marriott in Cambridge gave us one immeasurable tactical advantage: we walked. While the automotive gridlock around Kenmore Square took on the character of the Siege of Yorktown—horns echoing across the asphalt like musket fire—we simply strolled across the Boston University Bridge, enjoying the river breeze and feeling smugly superior to everyone trapped behind a steering wheel. Fenway, built in the spring of 1912, holds rough...
Post a Comment
Read more

Engineering Beef Stew

On July 2nd—Day Two of what I call The Great Un-Working —I sat down with my morning notebook to map out this new chapter of my life. One goal made the list in bold ink: Learn to Cook. At seventy, I was adding a skill most people master before they’re old enough to drive. Before you judge me, understand our household ecosystem. Lori is a phenomenal cook. For decades, she’s made meals so effortless and delicious that restaurants seem unsatisfying . My contribution to the culinary arts during my bachelor years–tuna mixed into Kraft Mac & Cheese. Let’s just say I wasn’t threatening her spot on the Food Network. But retirement changed the equation. I’m officially off the clock while Lori is still working. And I had a lovely thought: Wouldn’t it be wonderful if she came home after a long day to find dinner waiting? She loved the idea. Then came the question that haunted me for weeks: “What do you want to make?” I had no idea. Apparently, the first step in learning to cook is deciding wh...
Post a Comment
Read more