Noise-cancelling headphones can mean the difference between feeling refreshed after a long flight and being cranky as hell. The constant background noise of a plane, train, or bus engines can be fatigue us even if we don’t notice it. The path to noise-cancelling headphones started back in 1978 when Dr. Amar Bose tried on a pair of regular headphones on a flight home from Zurich and couldn’t hear the music over the roar of the jet engine. He set up a research project at the Bose corporation (yes, that Bose) to see if there was a way to actively cancel out external noise.

How Noise Cancellation Works

How noise cancelling headphones work

Image Credit: Centerpoint Audio

Noise-cancellation works via a process called Active Noise Control (ANC). Microphones on the outside of the headphones’ ear-cups pick up external noises in the environment and generate an ‘anti-noise signal’ that cancels out the external noise via ‘destructive interference”. If you want to learn more about it, Howstuffworks has an excellent article on the specifics of the entire process.

In terms of selecting headphones, this process means a few things for us consumers:

  • NC (noise-cancelling) headphones are better at blocking out constant noises, like the engines of airplanes or buses. This means that you can still hear important safety announcements.
  • The noise-cancelling circuitry required for them to operate inherently reduces audio quality.
  • They may introduce additional noise.

7 Tips to Consider When Buying Noise-Cancelling Headphones:

  1. Rechargeable or replaceable batteries? – This tends to come down as a matter of preference. Rechargeable batteries (usually litihium-ion) are smaller and charge via USB. This can be handy when you’re on a long flight and you’re able to charge your headphones via your laptop. However, some people prefer having replaceable batteries, since they’re available at any airport. I haven’t seen a set of noise-canceling headphones that did not use “AAA” batteries.
  2. What’s the Noise-Cancelation percentage?– Usually headphone manufacturers will mention how much external noise they cut out. Budget NC headphones will block out 70-85%, whereas the $300 range NC headphones usually block out over 90%.
  3. What’s in a Name? – Quietcomfort, Noisegard, Quietpoint, these are the names of the noise-cancelation technology each set of headphones uses. All of these technologies work differently, and are proprietary, which means that they all sound different from each other. If you like one Sennheiser NC headphone, chances are you’ll like another, since they have the same technology behind them. The best one? Bose’s Quietcomfort.
  4. You Don’t Need an Amp – Headphone amps will make any set of headphones sound better…except for noise-canceling headphones. Why? NC headphones already have an amplification circuit built into the headphones themselves.
  5. On-ear over Over-ear– Most manufacturers have one of each set of NC headphones on the market (think of Bose’s Quietcomfort 15’s and the Quietcomfort 3’s). Over-ear headphones tend augment the noise-cancelation by forming a seal around the ear. The downside is that heat accumulates in your ear. Sometimes these headphones will almost have too much clamping pressure on your ear as well. On-ear headphones aren’t quite as effective but are usually more comfortable.
  6. Would You Like Bluetooth as Well?– Some headphones (like Sennheiser’s PXC 310) are combination noise-canceling and bluetooth, which means that you don’t have to bother with cords. The Bluetooth headphones tend to be competitively priced as well, meaning that it comes down to personal preference. The downsides? Bluetooth streaming isn’t as high quality as a wired connection, and depending on what kind of smartphone/tablet/laptop your streaming from, sometimes they don’t support the same Bluetooth protocol.
  7. Most Importantly, it’s important to understand that the technology noise-canceling headphones uses negatively affects sound quality, so if you’re looking for $300 headphones with top notch sound quality, then you may want to get regular over-ear headphones instead.