Welcome to our deep dive into the world of active vs passive noise-cancelling headphones. In this article, we will not only explore the unique features and benefits of both these technologies but also answer a list of relevant questions to help you make an informed decision about your next audio investment.

Join us as we dive into the fascinating world of active vs passive noise cancelling, uncovering the differences, advantages, and potential drawbacks of each to guide you towards the perfect soundscape experience.

What Is Passive Noise Cancellation (PNC)?

Passive Noise Cancellation (PNC) is like having a bulky door between you and a noisy room – it’s the physical barrier that your headphones or earbuds create that keeps a lot of the outside world’s sounds from entering your ears. There are no fancy electronics at work, just good old-fashioned physics!

active vs passive noise cancelling
Image Credit: Bose

This sound-blocking is achieved by using heavy-duty materials and clever design. Over-ear headphones might pack dense foam into the ear cups, and in-ear buds are designed to plug up your ears effectively. This creates a kind of sonic seal that stops a some of the noise from getting to your eardrums. It’s a bit like stuffing your ears with cotton balls to block out noise, just more advanced and comfortable.

PNC is particularly good at keeping out higher-pitched sounds, like people chattering or birds chirping. However, for lower, rumbling noises like a truck engine or air conditioning unit, you might need something a bit more high-tech like Active Noise Cancellation. We will talk about this later in this article.

How Was Passive noise cancellation (PNC) Invented?

Passive noise cancellation isn’t so much an invention as it is a natural property of certain materials and structures. It’s been known for centuries that certain materials can block or absorb sound to some extent. For instance, thick walls or heavy curtains can muffle the sound from outside, providing a primitive form of passive noise cancellation.

The application of this principle to personal audio devices like headphones and earbuds, however, is more recent. The design and materials used in these devices can significantly impact how much external noise they block. Over-ear headphones, for example, physically cover the ears to block out ambient noise, while in-ear headphones or earbuds can create a seal in the ear canal that prevents sound from entering.

As technology and understanding of acoustics have evolved, manufacturers have been able to design headphones and earbuds with increasingly effective passive noise cancellation. For example, memory foam ear tips can adapt to the shape of the user’s ear canal, providing a better seal and hence better noise isolation.

So, passive noise cancellation is more about application of known acoustic principles in the design of audio devices, rather than a specific invention. As for who first applied these principles in this way, it’s difficult to say, as many early headphone and earphone designs incorporated elements of passive noise cancellation.

Best Passive Noise Cancellation Headphones

Some of the best passive noise-canceling headphones include the Bose QuietComfort 35 II for its superior comfort and sound quality, the Sony WH-1000XM4 for its excellent passive noise isolation, and the Shure AONIC 50 and Sennheiser HD 660 S for their professional-grade sound quality. For in-ear options, the Etymotic Research ER4SR offers significant noise isolation due to their deep-insertion ear tips. 

Pros and cons

  • The Bose QuietComfort 35 II is renowned for its comfort and sound quality but can be a bit bulky for some users.
  • Sony WH-1000XM4 on the other hand, offers excellent passive noise isolation and top-tier sound quality, although its battery life may be a concern for some, especially with active noise cancellation enabled.
  • Shure AONIC 50, designed with studio professionals in mind, provides high-quality materials and superb passive noise isolation, but they come at a higher price point and might be too large for some people’s preference. The Sennheiser HD 660 S headphones deliver acclaimed sound quality and a comfortable design, but being open-back, they are not the best for noisy environments.

For in-ear options, the Etymotic Research ER4SR provides superior passive noise isolation due to deep-insertion ear tips, but this design might not be comfortable for all users. As always, the best choice will depend on your personal needs, budget, and comfort preferences.

Is Passive Noise Cancellation Harmful?

Passive noise cancellation, or noise isolation, is generally considered safe and non-harmful. It simply uses physical barriers such as ear cups or earbuds to block out ambient noise. No active electronic noise-canceling technology is used in passive noise cancellation, which makes it safer because it doesn’t introduce any additional sounds into your ears.

However, it’s important to note that any type of headphone or earbud can potentially contribute to noise-induced hearing loss if misused. Listening to music or other audio at excessively loud volumes over long periods of time can damage your hearing. This is a risk regardless of whether the headphones or earbuds you use have passive noise cancellation.

Moreover, using passive noise cancellation devices in certain situations can be risky because it can isolate you from your surroundings to a point where you may not be aware of potential dangers. For example, using them while walking in a busy city might prevent you from hearing car horns or other warning sounds.

So, while passive noise cancellation itself is not harmful, it’s important to use such devices responsibly to protect your hearing and maintain awareness of your environment.

What is Active Noise Cancellation?

Image Credit: Samsung

Active Noise Cancellation (ANC) is an advanced technology utilized in audio devices, such as headphones and earbuds, designed to minimize unwanted ambient sounds. Unlike traditional soundproofing or noise isolating methods that aim to physically block background noise, ANC takes a more proactive approach. It functions by generating an “anti-noise” signal that mirrors the incoming noise in real time, but with an inverted waveform. When the anti-noise and the ambient noise collide, they effectively cancel each other out due to a principle called destructive interference. This significantly reduces the perceivable volume of the external noise, allowing users to focus more on their music, calls, or other audio, even in noisy environments.

How Was ANC Invented?

Image Credit: The Better India

Active Noise Cancellation (ANC) technology owes its invention to Dr. Lawrence Jerome Fogel, an American pioneer in the field of automation and remote control systems [1]. The need for noise cancellation initially arose in the aviation industry as a way to improve the audio communication experience for pilots who had to contend with the loud noise of aircraft engines. Dr. Fogel, recognizing this problem, devised an innovative solution and filed a patent for a noise-cancellation system in 1957.

His groundbreaking design involved using electronics to produce an opposing sound wave that could neutralize the unwanted ambient noise—a principle that would come to form the basis of modern ANC technology. Over time, this revolutionary concept was refined and eventually made its way into consumer electronics, finding particular use in enhancing the audio quality of headphones and earbuds.

Best Active Noise Cancellation Headphones

Among the top headphones with active noise cancellation, there are:

  • Sony’s WH-1000XM5 offers an exceptional blend of sound quality, comfort, and noise cancellation.
  • Bose’s QuietComfort 45 provides a lightweight design, enhanced noise cancellation, and all-day wearability.
  • Apple’s AirPods Max delivers a premium audio experience, seamless connectivity, and integration with Apple devices.
  • Bowers & Wilkins PX7 S2 showcases superb sound reproduction and a luxurious design.
  • Lastly, the Sennheiser Momentum 4 Wireless excels in endurance, comfort, and sound quality [2]. 

Pros and Cons

  • Sony WH-1000XM5 offers excellent sound quality, superior noise cancellation, and a comfortable design. Its multipoint pairing, ambient audio monitoring, and intuitive controls are additional advantages, but the higher price compared to previous models may be a drawback.
  • Bose QuietComfort 45 features a lightweight and comfortable design, improved noise cancellation, and a long battery life. The transparency mode and customizable sound with EQ adjustments enhance the listening experience, but the inability to turn off noise cancellation without activating transparency mode is a limitation.
  • Apple AirPods Max offers premium build quality, exceptional sound, seamless integration with the Apple ecosystem, and intuitive controls through the digital crown. However, the higher price, lack of compatibility with non-Apple devices, average battery life, and subpar carrying case are considerations.
  • Bowers & Wilkins PX7 S2 showcases a luxurious design, superb sound quality, physical controls, and competitive battery life, but the absence of a traditional headphone cable output and lack of AAC codec support may be drawbacks.
  • Sennheiser Momentum 4 Wireless stands out with its impressive battery life, exceptional comfort, superior noise cancellation, and detailed sound quality. The headphones support multipoint connectivity but may occasionally auto-activate and connect to devices inside the case.

Is Active Noise Cancellation Harmful?

Active Noise Cancellation (ANC) technology, in and of itself, is not harmful. As aforementioned, it functions by creating an inverse sound wave to counteract ambient noise, and this process does not pose a risk to human hearing.

However, potential harm can arise from how individuals use their ANC-enabled devices. For instance, if ANC leads users to feel they can safely listen to audio content at higher volumes or for prolonged periods, this can potentially contribute to noise-induced hearing loss.

Furthermore, users should be mindful that the noise cancellation capabilities of these devices can create a sense of isolation from their surroundings, which may pose safety risks in certain scenarios, such as walking near traffic. Hence, while ANC technology poses no direct harm, responsible usage is essential to ensure safety and protect hearing health.

What’s the Difference Between Passive Noise Isolation vs Active Noise Cancellation?

When comparing active vs passive noise cancelling, it should be noted that both distinct methodologies are employed in audio devices with the goal to minimize ambient noise. They operate on fundamentally different principles. Passive Noise Isolation relies on the physical design and materials of headphones or earbuds to create a mechanical barrier between your ear and the ambient sounds. This technique, akin to plugging your ears with your fingers, effectively blocks out a significant portion of external noise.

In contrast, Active Noise Cancellation utilizes advanced electronic technology to actively counteract ambient noise. It generates an ‘anti-noise’ signal, with the same frequency and amplitude as the incoming noise but with an inverted phase. When these two sound waves intersect, they undergo destructive interference, canceling each other out and reducing the perceived volume of ambient noise. While both methods aim to provide a better listening experience, they do so through contrasting mechanisms of active vs passive noise cancelling.

Which has Better Sound Quality?

The sound quality of headphones or earbuds is not solely determined by the presence of Active Noise Cancellation (ANC) or Passive Noise Isolation. It also depends on various factors like the quality of the audio drivers (speakers), the design of the ear cups or ear tips, the audio codecs supported, and the quality of the source audio itself.

However, when it comes to mitigating the impact of external noise on your listening experience, both ANC and Passive Noise Isolation can play significant roles. ANC can be particularly effective at reducing low-frequency noises such as the hum of an airplane engine or a running AC unit, thereby allowing for a cleaner audio experience in such environments. Conversely, Passive Noise Isolation is generally more effective at blocking out high-frequency noises like people talking or keys clacking.

One thing to note is that some ANC headphones might introduce a slight hissing sound or minor audio distortions due to the noise cancellation process, which could potentially impact sound quality. However, advancements in technology have made these issues less noticeable in high-quality ANC headphones.

In summary, both ANC and Passive Noise Isolation can enhance the sound quality by reducing the intrusion of external noises. However, the overall sound quality will also be significantly influenced by other aspects of the headphone or earbud design and technology. 

Which is More Effective?

The effectiveness of both Active and Passive Noise Cancelling. depends largely on the kind of noise you are dealing with. Active Noise Cancelling (ANC) is particularly good at cancelling out constant, low-frequency noises, such as the drone of an airplane engine, the hum of an air conditioner, or the rumble of a train. This is because the technology is designed to produce inverse sound waves that effectively neutralize these types of sound.

Passive Noise Cancelling (PNC) can be more effective for blocking out higher-frequency noises, like human voices, keyboard typing, or sudden, sharp sounds. It relies on the physical design of the headphones or earbuds to create a seal against your ears, thus blocking external noise from entering.

Therefore, the effectiveness of ANC versus PNC is not a one-size-fits-all answer. It can vary based on the specific noise environment, as well as the quality of the headphones or earbuds being used. Some high-end devices combine both technologies, offering the best of both worlds.

The Benefits Of Noise Cancelling

Noise cancellation can enhance focus, reduce distractions, and provide a superior audio experience. It’s worth noting that Dr. Amar Bose invented the first noise-cancelling headphones in the late 1970s after becoming frustrated with the amount of engine noise during a flight.

Do Noise-Cancelling Headphones Work Without Music?

Yes, noise-cancelling headphones do work without music. The Active Noise Cancellation (ANC) feature on these headphones works independently of any music or audio being played.

When turned on, ANC will produce anti-noise signals to cancel out ambient noise, creating a quieter environment. This can be particularly useful in loud public spaces, during travel, or in any situation where you wish to minimize external noise, even without listening to any audio content.

Passive vs. Active Noise Cancellation: Which Should You Go For?

Whether you should go for Passive Noise Isolation or Active Noise Cancellation depends largely on your specific needs and circumstances. If you’re often in environments with low-frequency noise like the hum of engines, airplanes, or air conditioning units, ANC headphones might serve you better. On the other hand, if you’re more concerned with blocking out high-frequency noise such as human voices or you prefer not to rely on battery-powered features, headphones with good Passive Noise Isolation could be a better fit.

Active or Passive Noise-Cancellation: Which is Better?

Image Credit: Bose

Neither method is categorically better than the other; they simply excel in different areas. Active Noise Cancellation is better at reducing low-frequency, consistent noises, while Passive Noise Isolation is generally more effective against high-frequency sounds.

Some high-quality headphones incorporate both methods, providing a comprehensive noise reduction solution. Your personal preference, listening habits, and the typical environments in which you use your headphones will largely determine which method is “better” for you.

Active vs Passive Noise Cancelling Takeaway

Grasping the underlying principles and differences between active vs passive noise cancelling methodologies is a crucial step toward selecting the ideal pair of headphones to meet your unique requirements in noise cancellation. Each of these technologies has its own set of strengths and is crafted to augment your auditory experience by mitigating unwanted external noise. Your ultimate choice between Active Noise Cancelling (ANC) and Passive Noise Cancelling (or Passive Noise Isolation) will depend on various factors, including your personal needs, lifestyle, and the sort of ambient noise you frequently encounter.

It’s worth noting that the newest generation of headphones is blurring the lines by integrating both ANC and Passive Noise Isolation techniques. This combination harnesses the power of both approaches to deliver superior noise cancellation across a broad frequency range. These advanced headphones offer a more immersive and undisturbed listening experience by tackling high-frequency and low-frequency noises.

Regardless of the technology you opt for, remember that responsible usage of headphones is paramount for the protection of your auditory health. Enjoy the silence that modern noise-cancelling technology offers, but do so with the awareness and care for your hearing.

References:

[1] https://www.soundplanning.co.uk/blog/noise-cancelling-headphones-the-beginning/

[2] https://www.theverge.com/21345733/best-noise-canceling-headphones

Eleftheria Georganti
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Eleftheria's world revolves around sound - whether it's designing high-quality audio applications, crunching numbers in audio signal processing (DSP), decoding room acoustics, listening to music or crafting the latest hearing aid technology and new features. She has a professional career spanning over 15 years and a strong research record (over 40 articles and patents) and has been the driving force behind top-notch products at leading hearing aid and audio tech companies. But what really makes her enthusiastic is sharing what she knows. As an avid writer, she loves spreading the word on the science of hearing, hearing aids and health technologies. Her ultimate goal? To give people with hearing impairments the insights they need to live their best life.

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