Are noise-cancelling headphones effective in the office?
I have been using noise-cancelling headphones and earbuds in the office for three years. They help a lot, but I wish I knew what to expect before buying such headphones. In this article I will describe what is like to use noise-cancelling headphones in the office and how do they work.
How much do noise-cancelling headphones help in the office
Without further ado here is how effective are the noise-cancelling headphones in canceling out the noisy office environment. The following numbers are based on using Bose Noise Cancelling Headphones 700 with active noise-cancelling turned on and without music. The percentages describe how much of the noise is blocked.
Conversations near you (less than 13 ft / 4 m)
Conversations far from you (more than 20 ft / 6m)
Keyboard & mouse sounds
Air-conditioners & water dispensers
Coffee machines & printers
Music from coworker’s headphones
Traffic from outside
For more in-depth explanation why noise-cancelling phones are not so effective with human voice, but extremely effective in a plane flight, please read the following section.
What you should know about noise-cancelling headphones
In this section I answer the most popular questions related to the noise-cancelling headphones. You will understand how they work and at the end I will give you a tip whether or not they are the right solution for a noisy office.
What is Active Noise Cancellation (ANC)?
Each sound has a wave. To cancel this wave, you could produce an opposite/negative wave. When both waves are pointed to your ear they cancel each other out and produce a new wave. Science calls this destructive interference.
How noise-cancelling headphones apply this in the real world? They have microphones which capture and measure all the sound waves. Then, the headphones use software to calculate the opposite sound waves. Finally, the headphones play the opposite waves in real-time, effectively cancelling the initial sound waves. This works because the microphones could capture sound waves before they reach your ear.
What is Passive Noise Isolation (PNI)?
Passive noise isolation refers to how well the headphones reduce outside noise by physically covering your ears. This is related to the material and design used to produce the headphones.
For better understanding, you can picture an industrial earmuffs - they are solely designed to isolate noise. They are made with special insulating materials. Earmuffs rely on clamping force for better isolation and are not comfortable for prolonged use.
Each pair of headphones has some level of passive noise isolation.
What is Hz and in what frequency range do noise-cancelling headphones reduce noise best?
Hertz (Hz) is a unit for measuring frequency. 1 Hz equals 1 cycle per second. Please see the following picture to better understand what 1 full cycle is:
When the sound wave oscillates 360 degrees, it makes a full cycle. And if this happens in a second, this is 1 Hz.
This is the visual representation of 250 Hz and 1000 Hz:
Here you can hear the following frequencies:
Basically low frequency sound wave means low pitch sound and high frequency sound wave means high pitch sound.
Noise-cancelling headphones work best for frequencies between 20 Hz and 1000 Hz.
What is dB and how much decibels noise-cancelling headphones can reduce?
Decibels (dB) measure sound intensity or loudness. dBa, dBA or dB(a) measure sound loudness perceived by a human ear. The A-weighted decibels are widely adopted for sound loudness measurement. It is very important to understand the correlation between sound loudness (dB) and sound pitch (hZ). Here is a visual representation:
Here are some examples:
Noise-cancelling headphones reduce up to 20-30 dBA for low frequencies (up to 1000 Hz or 1 kHz).
Why noise-cancelling headphones cannot cancel out human voice so well?
A normal conversation in the office has a loudness between 20 dBA and 60 dBA and a pitch (frequency) between 500 Hz and 3000 Hz. Potentially, the human voice could reach up to 8000 Hz. The range is called "speech banana" because of the shape it makes on the audiogram from above.
Noise-cancelling headphones are not so effective with human voice because they cannot cancel out frequencies above 1000 Hz. Also, such headphones struggle with reducing sounds which change their frequency so rapidly.
Why noise-cancelling headphones work best for plane flight or AC noise?
When you are flying in a plane, the humming engine noise you hear is 75-80 dBA and it has a low frequency in the range 10 Hz - 300 Hz. This is why the noise-cancelling headphones are so effective in the sky. A noise from an air-conditioner is low-pitched, too, so it is perfect for cancelling out. Also, these types of sounds are steady and do not change so much.This improves the headphones effectiveness even more.
What is the “eardrum suck” phenomenon?
It has been reported by some users they experience a sense of change in the pressure in their ears while using headphones with ANC turned on. This phenomenon happens only when using a high-end noise-cancelling over-the-ear headphones. It turns out there isn’t really a change in the pressure. This is a side effect from the required software, used to achieve such a high level of noise-cancelling. Your brain thinks you have a change in pressure and makes your eardrums feel uncomfortable. However, over time you get used to this and the discomfort goes away. For scientific explanation, please read Brent Butterworth’s article.
Should you buy noise-cancelling headphones for the office?
Noise-cancelling headphones are very effective at reducing persistent low-frequency humming and droning sounds. So if you need to reduce the noise from anything except human voice in your office environment, I suggest you buy a pair of such headphones.
If you want to buy noise-cancelling headphones for the sole purpose of reducing the noise of the conversations in the open office space, I would advise you to buy a regular pair of headphones instead. They would do nearly the same job and would be a lot cheaper.
Which are the most effective noise-cancelling headphones for the office?
Bose released their latest headphones on the 30th of June, 2019 - Bose Noise Cancelling Headphones 700. They are a successor to Bose QuietComfort 35 II. The killer feature of the new pair of headphones is the new 4-microphone system which isolates your voice from competing noises when you are taking a call. This feature really crushes the competition, but which pair has a better noise-cancelling? I’ll share my two cents on noise-cancelling and comfort.
The word "comfort" is missing
The new pair of headphones Bose Noise Cancelling Headphones 700 does not have the word "comfort" in its title anymore. Why not? It turns out some users report the comfort is not as good as with the older model, Bose QuietComfort 35 II. The new headphones are heavier, with less comfortable ear cups, increased clamping force and they put more pressure on top of your head. In my opinion the higher clamping force increases the passive noise isolation even more, but it makes you take a break from wearing the headphones after ~60 minutes.
The best noise-cancelling in the business
Bose Noise Cancelling Headphones 700 has a sophisticated 8-microphone noise-cancelling system. 6 of them are used to isolate your surroundings. 2 of those microphones along with other 2 help to isolate your voice when taking a call. It provides a slightly better noise-cancelling than QuietComfort 35 II. The new pair of headphones has 11 ANC levels vs 3 ANC levels for the old headphones. Bose Noise Cancelling Headphones 700 delivers the best noise-cancelling in the business!
Conclusion
You should definitely go with the latest and greatest - Bose Noise Cancelling Headphones 700! They are expensive, but, after all, you are paying for the best noise-cancelling technology on the market!
