Since Apple launched AirPods Pro noise reduction headphones, noise reduction has become a standard feature on many mid-and high-end TWS headphones, and noise reduction features have become the main selling point for more and more categories of headphones. But actually, noise reduction is a more general term, it is actually divided into active noise reduction and passive noise reduction. This article will briefly introduce these two kinds of noise reduction as well as the difference.

Types of noise cancellation

Active Noise Cancellation

The active noise reduction function is to achieve the effect of noise reduction by generating the reverse sound wave which is equal to the external noise and neutralizing the noise. Active noise-canceling earphones have noise-canceling circuits to counteract the external noise. Most of them are designed with an over-head design. The earplug cotton and earphone shell can be used to block the external noise for the first round of sound insulation, also in order to have sufficient space to install the active noise reduction circuit and power supply.

Passive Noise Cancellation

Passive noise-reducing earphones are designed to block out noise by enclosing the ear to form an enclosed space, or by using sound-proof materials such as silicone earplugs. Because the noise is not processed by the noise reduction circuit chip, it can only block the high-frequency noise, and the effect of low-frequency noise reduction is not obvious.

Pros and cons of active noise and passive noise cancellation

Passive Noise Cancellation: Passive noise-canceling headphones take advantage of physical features to isolate the external noise from the ear and use different materials to block the noise from entering the ear, just as a firecracker covers the ear with its hand.

Pros

• Very effective for high-frequency sounds. Noise can generally be reduced by about 15-20 db. This noise reduction method is the most traditional, universal, its price relative to the active noise reduction headphones also to be low.
• Large noise reduction space. Passive noise reduction for high-frequency signal isolation effect is good, so the noise reduction space is large. Like the soundboard by the highway. However, for low-frequency noise in small spaces, such as air-conditioning noise, aircraft engine noise and other noise effects are greatly reduced.

Cons

• Can’t neutralize the noise. Most of the portable noise cancelling headphones we see are passive noise cancelling, with in-ear earplugs and closed earphones providing some degree of noise isolation, but there is no way to neutralize the noise to achieve a quiet listening effect.
• It’s too loud. Many passive noise cancelling headphones turn up the volume of the original sound to reduce the noise. This is not very good for the ear health, so we need to carefully check and compare the tone of the noise cancelling headphones.

Active Noise Cancellation: The theory of active noise reduction is very simple, sound propagation is achieved through the vibration of the medium, wave, and wave if the reverse phase between the theoretical conditions will be achieved to offset. Active noise reduction involves the processor creating an opposing sound that neutralizes the noise. In acoustics this is called “Destructive interference”.

Pros

• Pure timbre. Active noise reduction makes up for the lack of passive noise reduction at low frequency, and brings users more pure sound quality. For example, the noise of public places, cars, trains, etc. , more appropriate to the user’s use of the scene.
• To protect the user’s hearing. The active noise canceller is equipped with a dedicated noise cancelling circuit, including a custom high sensitivity MEMS silicon microphone and a professional level noise cancelling chip, which cancels out noise by receiving and analyzing the external noise spectrum and generating signals in the opposite phase. Why do you say that? We assume that the ambient noise (dB) is constant, and that the volume of the phone that can meet the listening needs without noise reduction headphones is 20 bars; with noise reduction headphones, it takes only 10 bars to meet the listening needs. So from this point of view, noise-reducing earphones for the hearing protection is very prominent.

Cons

• High cost. Active noise reduction system is necessary equipment pickups, processing chips, speakers, each part to ensure high quality in order to achieve the final effect, so the cost is higher.
• Energy consumption. Active noise reduction headphones are built with an acoustic processor, so turning on the active noise reduction mode can have some detrimental effects on the wireless headset’s battery life.

Active noise reduction and passive noise reduction have their own advantages and disadvantages, we choose to buy according to their own preferences and needs to choose their own headphones.

Active noise cancellation VS positive noise cancellation headphones

Which has better sound quality?

If you’re comparing two sets of earbuds with similar build and tuning quality, the earbuds with better passive noise isolation will sound better than the ones that rely on active noise cancellation to block out ambient noise.

The reason passive noise isolation sounds better is that ANC earphones and headphones create noise to cancel environmental sounds. This effectively adds distortion to your music. Passive noise isolation results in a truer representation of your music while blocking outside noise.

Which is more comfortable?

Passive noise isolation is best achieved through custom-moulded and custom-fitted earbuds and earphones. Earbuds and headphones with active noise cancellation typically aren’t custom-fitted to your unique ears. That means your ANC earbuds will fatigue your ears more quickly because you’re putting pressure on certain parts of your ear more than others.

With a custom fit, you won’t have to worry about pressure points. Earphones like K7 form to your ears, which makes for a more natural, comfortable feel.

Which does a better job at reducing outside noise?

Passive noise isolation and active noise cancellation each do a great job of reducing outside noise. However, each has its strengths and weaknesses depending on the range of the frequencies being blocked.

Earbuds with passive noise cancellation can lessen mid- to high-frequency noises by about 15dB to 30dB. Meanwhile, active noise-canceling headphones and earbuds work better to reduce lower frequencies. ANC can cut ambient noise overall by an average of 30dB, while lawnmowers, subway traffic and more can be reduced by as much as 60dB.

In other words, earbuds with passive noise isolation reduce mid-high frequencies better while ANC does better with low frequencies.

Another thing to consider in regards to reducing outside noise is that ANC headphones work best at reducing constant background noise, not sudden transient noises. Sudden noises, like a car honking its horn outside your coffee shop, occur too quickly for your ANC headphones to detect and combat these sudden sounds.

Meanwhile, passive noise isolation reduces all incoming sound by roughly the same amount. So ANC headphones won’t block out that horn at all, but your custom-fit earbuds will reduce it as much as they reduce constant noise.

Which consumes more power?

Even if your passive noise isolation earbuds use Bluetooth to operate, they’re still consuming less power than Bluetooth earbuds with active noise cancellation.

Earbuds and headphones with ANC require power to create the noise that cancels ambient sounds before they hit your ears. However, products like UE FITS only need power for Bluetooth. That results in longer battery life, other elements considered. you can enjoy the high-fidelity sound and passive noise isolation without ever having to wonder if you remembered to charge them before boarding that six-hour flight.

Which is more affordable?

The cost of earbuds and earphones can vary dramatically depending on the brand.But no matter which brand, active noise reduction headsets are more expensive than passive noise reduction headsets, and the equipment necessary for active noise reduction systems are pickups, processing chips, and speakers, each part of which must be of high quality to achieve the final result, so it’s more expensive.

Which is better when you’re not listening to music?

If all you want to do with your earbuds is block out ambient noise, active noise cancelling earbuds may be a fine solution, especially if you mostly want to block out low frequencies. ANC earbuds can block out up to 60dB of lower frequencies, like sounds from subway trains. Keep in mind that active noise cancelling earbuds aren’t completely noise-free—you’ll still hear a gentle hiss from your earbuds’ noise floor. This noise always exists in ANC headphones, but is most apparent when you’re not listening to music but still have the active noise cancelling turned on.

Which are more portable?

When it comes to earbuds, models with passive noise isolation are often smaller than those with active noise cancellation. That’s because active noise cancellation requires an onboard microphone in order to neutralize the ambient sounds. However, portability varies by brand and model of earbuds.

Is ANC True Wireless Earbuds worth it?

If you wish to protect your hearing, reduce environmental distractions, and enjoy a better audio experience, then this technology will surprise you with its impactful results.

If travel a lot on planes, and they are absolutely worth the price when flying. They’re also very useful if working in a noisy environment (screaming kids, whining engines and peeps and plobs everywhere, people coughing and people arguing). At your desk and at home, you may hardly ever use the noise canceling function, so if it wasn’t for the traveling, you could have gone for some cheaper ones w/o noise canceling.

If need to take the train to work and need to work on the train, the ANC headphones will help you concentrate because they block out all the distractions and background noise and let you really enjoy what I’m listening to. They have also come in really handy since you’ve been stuck at home in lockdown recently. You will be able to have your work calls and meetings easily, can block out any noises from your room.

If you work in an open office, it may be hard for you to focus on things. Then ANC earphones are absolutely worth it.

That depends on yourself. It depends on your wallet, it depends if you like the effectivity, and it depends on other things like comfort.

Is ANC earphones harmful, bad for ears?

According to the principle of the active noise reduction earphone, the built-in active noise reduction circuit first collects and analyzes the environmental noise, then through the analysis of the noise sound wave, creates the reverse sound wave, this sound wave and the environmental noise combine will cancel each other, when sound enters the human ear, the music is more pure because of the cancellation of the noise and the reverse sound wave.

Therefore, the active noise reduction headset is generally through the active generation of “Anti-phase noise”to real-time noise cancellation, in the open noise reduction effect is very obvious. Usually in a noisy and noisy environment, do not have to as the general headphone volume to suppress the noise. In this way, a long time to listen to music will not feel tired, to some extent, active noise reduction effectively protect the human ear hearing.

It’s true that wearing active noise canceling headphones can actually make music clearer in noisy environments, but some users of noise canceling headphones experience discomfort and tightness in their ears, sometimes when it gets bad, it can lead to nausea. So is this caused by the noise reduction in the headphones?

From the point of view of the noise reduction principle, if the reverse sound generated from the headphones can be exactly and noise cancellation, that is, the two can be exactly 180 degrees of phase difference, in this ideal state can experience the perfect noise reduction effect. But in fact, due to the imperfections of the various noise reduction headphone designs (such as chips, algorithms), more or less there will be a certain deviation. In the worst-case scenario, if you don’t maintain the exact 180-degree phase difference, the resulting error will cause the headset not only not to reduce the signal, but to amplify it, in fact, it is equivalent to doubling the noise! It’s also one of the things that hurt the human ear. If the noise reduction function plays the noise reduction effect is abnormal, it will affect the actual experience. But this is an isolated case, not a common one.

There is also a factor is the active noise reduction headset users are accustomed to personal wearing, the common active noise reduction headphones from the wearing way is generally divided into in-ear headphones and over-headed headphones.

The in-ear seal is relatively good, resulting in a change in the inner environment of the ear. If you wear them too long, or if they don’t fit properly, you may experience some discomfort. For example, the in-ear approach blocks the ear canal and air flow, making it the best habitat for bacteria. After long-term wearing, ear canal easy inflammation, infection, ear canal vulnerable organs may be damaged.

The head-mounted earphone is not only can not produce damage to the ear canal, but also can take into account the good airproof, guarantees the sound effect. However, headphone speakers will be larger, high power, volume size is more need to pay attention to. This is mainly aimed at the headset itself some of the factors on the human ear.

So what causes earmuffs and other symptoms of active noise reduction headphones? The effect of infrasound is now widely believed to be responsible. Scientific experiments show that infrasound can cause chest vibration, affect breathing, and cause nausea, headache and other phenomena. Infrasound is a sound wave with a frequency of less than 20 Hz, which is usually inaudible to the human ear. However, nature and industrial production almost everywhere there are infrasound sources, this infrasound usually mixed in the sound is no effect on people. But active noise reduction headphones do not produce infrasound, based on the masking effect of the human ear on sound. When noise reduction headphones help us get rid of most of the sound, the usually hidden breath of infrasound has become the protagonist, for infrasound sensitive people may have the corresponding physiological response.

So when you’re wearing active noise reduction headphones, try to keep them as busy as possible with music and other audio, keeping your brain busy with other frequencies, re masking the effects of infrasound, and taking them off when you’re not using them.

In fact, most of the active noise reduction headphones for the human ear side effect is basically minimal, it is still the city commuting, outdoor sports, reading and working in a variety of scenarios the best choice.

Do I really need ANC earphones?

It’s worth clarifying that active noise cancellation doesn’t improve the sound quality of your headphones per se, though it indirectly benefits the clarity of music and podcasts by removing distractions. As such, just about anyone can enjoy the upsides of ANC headphones.

They’re particularly useful for commuters and long-distance travelers, as plane engines and the trundling of trains are exactly the kind of consistent sounds that ANC excels at canceling out. ANC can also help you get some sleep on an overnight flight, even if you’re not listening to music.

The most common drawbacks to noise-canceling headphones are that they usually cost more than headphones without this technology and the fact that ANC reduces battery life.

One other potential downside to ANC is the reduction in situational awareness; for instance, reducing traffic noise could carry risks if you’re trying to cross a busy street. It’s often harder to tell when someone is trying to speak to you, too. Still, these don’t need to be reasons to avoid ANC headphones. Just exercise caution in situations where your lowered hearing capacity might be a factor — such as if you’re out for a run — or simply use normal headphones is OK.

Most ANC headphones have such a mode, and it repurposes the onboard microphones to amplify surrounding noises instead of canceling them out. This is handy for having a quick conversation or giving yourself some extra awareness, and you can switch between ANC and ambient modes at will.

Conclusion

After reading this article, you may have a general idea of active and passive noise reduction headphones. Then how to choose between ANC earphones and passive noise reduction earphones, it depends on your demands, if you need to use in flying, train, open office or other extremely noisy environments, then active noise-canceling earphones will be better. Second, it depends on your wallet, ANC headphones are far much expensive than passive ones. If you can’t afford ANC headphones for now, then passive ones also is a good choice.