What is Active Noise Cancellation in Earphones? Explained

You may have come across the term “ANC” or “Active Noise Cancellation” whenever you come across earphones or headphones. Active noise cancellation is an innovative technology used in modern-day earbuds, headphones, and related audio equipment.

Previously, Active Noise Cancellation technology was only present in giant headphones. But with the passage of time, it now envelops the tiny earphones as well.

The growing popularity of ANC earphones can directly be attributed to several factors that consumers want in next-gen audio equipment these days. Some of those factors are improved audio quality, enhanced focus, noise isolation, hearing protection, etc.

In this guide, I will explain to you in simple words what ANC technology is and why it’s important to have in the modern earphones of today.

What is Active Noise Cancellation?

Active Noise Cancellation (ANC) is a technology that uses special microphones and audio processing components to filter unwanted noise from the background. So, what this technology does is offer you the audio that you want to listen to or focus on.

The ANC technology generates special types of sound waves that are exactly opposite to the unwanted background noises. The sound waves generated via phase cancellation remove the background noises resulting in a clear and smooth sound experience.

How Active Noise Cancellation Works
ANC Diagram

The concept of “Noise Cancellation” is decades old and it falls back to the time when Paul Lueg first introduced this theory in 1933.

The first ANC headphone was created later on in 1950 by Lawrence J. Fogel. The modern ANC headphone as we see it today was then made by Bose Corporation back in the year 1989.

How Active Noise Cancellation Works?

In order to understand how ANC works, you will have to first understand the concept of “Phase Cancellation”.

Phase Cancellation

Let me explain this phenomenon with the help of Physics. For example, there are two people pushing a see-saw up and down. If one person pushes down and the other person pushes the see-saw up with the same force, then the see-saw won’t move much.

The same happens in phase cancellation, the inverted sound waves and the original noise waves cancel out each other’s effect, resulting in no sound or a faint sound hardly detectable by human ears.

how phase cancellation works
Source: Ledgernote

Phase cancellation also known as “Destructive Interference” in Physics occurs when two or more audio waves interfere with each other, resulting in a reduction of volume in frequencies.

Now that you are aware of Phase Cancellation, here’s how the whole ANC process works afterwards:

  • Microphones: The process of Active Noise Cancellation begins with the beamforming microphones that record the unwanted background noise. This noise includes traffic noise, people talking in the background, aeroplanes flying over your house, etc.
  • DSP: Once the unwanted noise is collected, the next step is the sound processing. The recorded noise is then sent over to the DSP or Digital Signal Processor which then flips the phase of the recorded audio.
  • Phase Cancellation: The phase-flipped sound is then played on the speakers of your earphones or headphones. This is where the Phase Cancellation occurs as the soundwaves cancel each other, resulting in no or minor noise.
Good to Know

The whole process of ANC is easily understandable with the help of Destructive Interference. In simple words, When two sound waves meet while out of phase, meaning their peaks align with troughs, they can cancel each other out, this is known as Destructive Interference.

Types of Active Noise Cancellation

Below are the main types of ANC found in modern earphones or headphones:

Feedforward ANC

In this type, the microphones for capturing the noise are placed outside the earpiece. The mic records the unwanted noise and then forwards it to DSP for further processing.

Feedback ANC

This setup uses a dual mic setup, within the ear cup and in front of the speaker. The external mic captures the outside noise whereas the internal mic captures the sound coming from the speaker.

The feedback ANC analyzes the outside and inside sounds and then adjusts the anti-noise signal for better hearing. This type of ANC is commonly used in hearing aids and high-end earphones.

Hybrid ANC

The Hybrid ANC combines the elements of feedback and feedforward ANC to deliver extraordinary hearing results. It uses external and internal microphones to capture and cancel unwanted noise.

The hybrid approach results in a superior and broader noise reduction spectrum with respect to a wide range of frequencies.

Adaptive ANC

Adaptive ANC was first introduced by Qualcomm back in the year 2020. This is the most advanced type of ANC found in premium-end headphones and earphones. Adaptive ANC adjusts the noise levels based on the algorithms and advanced sensors.

The technology is somewhat similar to hybrid ANC, however, Adaptive ANC makes use of processing software in order to detect the noise levels and frequencies, resulting in excellent noise reduction.

Benefits of Active Noise Cancellation

ANC offers a lot of benefits, some of which are discussed below:

Improved Audio Quality: As ANC helps eliminate the unwanted noise in the background, you get an immersive listening experience. ANC in earbuds enhances the audio call quality, especially in noisy environments where the clarity of sound matters. ANC earphones or headphones can reduce up to 60 dB of low-frequency noises under 1 kHz.

Hearing Protection: One of the main reasons I prefer getting ANC earphones is that they protect your hearing in loud and noisy areas. Sometimes, I simply plug in my ANC earphones even if I’m not listening to any audio. It’s because the ANC features protect my hearing whenever passing through railway stations, airports, heavy traffic, etc.

Concentration: If you are working on a project that needs a lot of attention, I would recommend you wear ANC headphones or earbuds. This would result in blocking the background noise as you pay full attention to your work. Whenever I’m writing an article or something important, I just wear Soundcore ANC earbuds.

Reduced Fatigue: Loud or unwanted noise can result in mental fatigue and stress. ANC helps in creating a more peaceful and calming auditory environment for you.

Limitations & Challenges With Active Noise Cancellation

Although Active Noise Cancellation gives you a lot of edge in improving your hearing experience, it also comes up with some challenges that you may encounter.

Battery Life:

Active noise cancellation consumes more battery power in order to keep the noise-cancellation circuit running. This could be a huge concern for users who need earbuds or headphones to last long hours before they recharge them. Earbuds or headphones with ANC turned on do not last more than a few hours.

Limited Effectiveness:

As you know ANC depends upon the DSP for signal processing, it takes some time to cancel the noise effect depending upon the environment you are in. Sometimes, ANC can introduce subtle changes to the audio quality, including a feeling of pressure or “cabin effect.”

This is more noticeable if you are an audiophile or a user with higher sound-quality standards. ANC works best in environments where there is reactive noise in the background. For example, if you are inside a room with a fan turned on, an airport, a train station, or an area with a humming sound, then ANC won’t have any issues reducing the noise.

But in areas where the frequency of sound changes every second or minute, ANC will take time in order to respond, this might affect your hearing experience. Also, ANC is less effective where the noise source is close to your ears, so keep this thing in mind before you buy ANC-enabled earbuds or headphones.

Cost and Complexity:

Active Noise Cancellation technology adds an extra cost to the earbuds, headphones, or any other device that you are buying. Implementing a high-quality ANC system into an earphone or headphones has a lot of complications, which then comes at a higher cost.

The Final Words

Making use of earphones or headphones that come with ANC technology would certainly improve your hearing experience by removing unwanted noise. The use of ANC not only improves the audio quality but also offers you hearing protection from unwanted loud noises.

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