How Do Noise-Cancelling Headphones Work?
- 21 Nov, 2018
Listening to music is one of the greatest pleasures in life. The best thing about music is how accessible it is, and how everyone has unique tastes. The best way to enjoy music is with the volume turned up high, and the world shut out. But, these high volumes can be damaging to our ears. We are also having to listen to music with outside distractions interrupting our experience. The solution to both of these problems is noise cancelling headphones. They completely block out outside noise. Due to this blocking effect, they allow you to stay in the zone and listen to your music at a much lower volume.
In this article, we explain the technology behind noise-cancelling headphones. We will also explain the differences that exist between passive and active noise cancelling technology.
- Why do you Need Noise Cancelling Headphones?
- What are Noise Cancelling Headphones & Who Invented Them?
- How does the technology work?
- Passive Noise Isolation
- Active Noise Reduction
- Are Noise Cancelling Headphones Perfect?
- How do I deal with noise I can’t cancel?
- How do I find the Best Noise Cancelling Headphones?
Why do you Need Noise Cancelling Headphones?
Music is more enjoyable to listen to when there are no outside distractions. There is a range of situations when external sounds can severely detract from your listening experience. An example of this is on the bus when your music has to compete with the various sounds of passengers. Another similar situation is loud flights. The high noise from flights can completely blare out the sound of your music. An open-office plan will have many distracting sounds. This can include sounds such as chatter.
Noise cancelling headphones allow you to shut off from the world and concentrate fully on your music. They are an adequate tool for taking a break from the business of the modern world.
What are Noise Cancelling Headphones & Who Invented Them?
Noise cancelling headphones rely on a specific type of technology to effectively block out background sounds. This allows a person to focus. It means they can listen to their music without interruptions. However, this technology also works without any music playing to achieve silence. These headphones work by limiting all unwanted ambient sounds. This occurs through the use of active noise control. Moreover, they also restrict high-frequency noise through the use of soundproofing.
The Bose group first developed noise cancelling technology. The founder of the corporation was on a flight in 1978. He could not concentrate because of the high level of noise. He then had the idea to work on headphones that could block out these sounds. On the plane journey itself, he began to work on some calculations. These would aid in the development of this technology. Dr. Bose formed an exclusive team after this flight. This team would work on this technology. They created a prototype which was used by pilots in 1986. The pilots were on a non-stop 9-day journey. They wore these prototype headphones made by Bose. The headphones helped them to maintain concentration. The first commercially noise-cancelling headphones were available in 1989 through the Bose Group.
How does the technology work?
Most modern noise cancelling headphones use a combination of technologies to produce an effective solution to blocking out unwanted noise. The primary technology in use is active noise control. This technology reduces outside sounds by replacing these sounds with the addition of a new sound.
These sound waves work to cancel out the unwanted sound waves. The technology is a bit complicated, but this is because the concept of sound is fairly complex. Sound is made up of a pressure wave which travels through the air. Active noise reduction creates a wave with the same amplitude as the outside sound, but one that is known as an "antiphase."
This process causes interference, and the two separate waves cancel each other out. The waves are said to be "out of phase," and the eventual result will be 0. The result is a massive reduction in hearing the unwanted outside noise.
Passive vs. Active Noise Isolation
There are two main forms of noise reduction and these consist of either passive noise reduction or active noise reduction.
Passive Noise Isolation
Passive noise reduction works straightforwardly. It achieves this by providing a perfect fit between the earbuds and your ears. The idea behind this is that sounds become trapped inside. Thus, outside sounds are unable to enter your ear due to the tight fit.
Also, this type of noise reduction works through the physical design of the headphones. This method of reduction is reliant upon suction to reduce outside sounds. The headphones have a circum-aural design. This is the optimum design to block outside noise. Consequently, it can work fairly effectively, but only if the fit is right.
Companies are starting to produce these headphones in various sizes. Nonetheless, the difference in shapes means that not everyone will be able to purchase a headphone that will fit snugly and comfortably. This method of noise reduction works relatively well. Although, it can be limited when sounds are particularly loud, or the fit isn't right.
The main difference between passive and active noise isolation is that active isolation is always working to block out founds. On the other hand, passive noise isolation is reliant upon the fit to provide the noise isolation.
Active Noise Reduction
This method of noise reduction is far more complex and is reliant upon sophisticated technology to block out unwanted sounds. This method is reliant upon producing a separate antiphase sound wave. This new sound wave cancels out the unwanted sound wave. These headphones come fitted with a small microphone. This mic can detect these outside sounds.
These headphones use some inbuilt technologies which provide an effective solution to unwanted sounds.
- Microphone - Used to pick up incoming sounds. It is continuously scanning to pick up new sounds.
- Noise Cancellation Circuit - This circuit uses the sounds collected by the microphone to create a basic fingerprint of the sound. The amplitude and frequency of the noise are noted.
- Speaker - A replacement wave travels from the circuit to the speaker. It eradicates the outside noise.
- Battery - This will usually be rechargeable and is required to ensure that the process is kept active. It is unable to work without a battery.
The process of active noise cancellation works continuously. It allows you to enjoy your music in an undistracted manner.
The technology works particularly well at blocking out low-frequency sounds. This includes steady sounds such as a fan or an engine. Active noise cancelling tends to get better results than passive noise isolation. Thus, this explains why this technology is in use by pilots. These type of headphones are reliant upon active technology that works to reduce unwanted sound.
However, many headphones that have this technology also take advantage of passive noise isolation. This works through the design of the headphones. Hence, it ensures that a consumer can get maximum isolation benefit.
Are Noise Cancelling Headphones Perfect?
It may seem like active noise cancelling headphones offer the perfect solution over regular headphones towards cancelling unwanted sounds. However, the reality is that these headphones have specific advantages and disadvantages when compared to regular headphones.
Safe Listening Levels
The obvious pros of using noise cancelling headphones are that they effectively block out unwanted sounds. Furthermore, they allow you to listen to music at much lower sound levels.
Active noise cancelling headphones usually need batteries. This can be an extra hassle because noise cancelling technology is power hungry. This power requirement means you will be required to undergo regular recharges.
They are also usually more pricey than regular headphones. This is important to keep in mind because the price difference can sometimes be very significant.
An important note to keep in mind is that noise cancelling headphones cannot cancel out ALL sounds. Although, they usually do a good job of cancelling out everyday sounds. However, the technology is not perfect at producing silence. Additionally, the performance of the noise cancelling technology can be incredibly variable across different models.
The sound quality is one of the most critical aspects of headphones. Some users have noticed a palatable difference between the quality of regular headphones and noise cancelling headphones. Nonetheless, this experience is entirely subjective. Furthermore, many people do not notice any significant differences in sound quality.
Most noise-cancelling headphones have a tighter fit. This is done to provide a seal at blocking outside sounds. The fit of these headphones can be uncomfortable when compared with regular headphones. Also, they also tend to be heavier than regular headphones. This can make them inconvenient when traveling.
Some people also complain about hearing a slight humming noise, when using noise cancelling headphones. Another well-known phenomenon is "ear fatigue." Your ears have to work harder due to the blockage of certain sounds. This creates more fatigue than listening through regular headphones. This consideration is why a fair few musicians do not use these headphones.
It is important to remember that this technology is not infallible, regardless there is usually a model that you can find which is a suitable match for your individual needs.
How do I deal with noise I can’t cancel?
- White Noise
We mentioned previously that this technology is not perfect at blocking out all sound. So you may be curious as to whether there are any methods for blocking out these type of sounds. There may be situations in which you require extreme focus. For this, we recommend listening to white noise. When noise cancelling technology doesn't work; white noise can be an effective solution to keeping yourself concentrated.
Once you start playing the music at a normal volume, your brain will automatically get accustomed to it. This process prevents you from being distracted by sounds not being canceled by your headphones.
- Foam Earplugs
Another way of dealing with very loud noises is through the use of foam earplugs. This method can be helpful for blocking out extremely loud sounds such as from construction sites and alarms. You can use foam earplugs to provide a snug fit around your ears. They offer a good solution to blocking noise when combined with noise-cancelling headphones and white noise.
How do I find the Best Noise Cancelling Headphones?
There are many noise cancelling headphones available to purchase. Each has different features and levels of sound quality. You should be sure to check reviews for your ideal headphones.
You should also ensure it matches your purpose. Some headphones will be more suitable for plane journeys. Others will be better suited for a daily commute.
The fit is also important. In this regard, you should make sure you find headphones that will be comfortable on your head. The tightness of some noise cancelling headphones can start to feel uncomfortable after a few hours of use.
The invention of noise cancelling technology has allowed pilots and other professionals to concentrate much better in their jobs. Noise cancelling technology is usually very effective, and it means we can block out the distractions of the outside world with ease. In most cases, they are superior to regular headphones. You should, however, shop around to find the perfect noise-cancelling headphones. It is vital that they suit your specific needs.
Overall, noise cancelling headphones allow us to enjoy the pleasure of music without the outside world ruining the experience. More importantly, they mean we can protect our ears from the dangers of high volume.