Noise Cancellation in Headphones: How Does it Work?

You may have heard about “noise cancellation” or “ANC” in relation to headphones and earphones.

These devices use special technologies to block out surrounding noise so that you can focus on the sounds you want to hear.

Noise cancellation includes various techniques to reduce unwanted noise from a sound stream.

This article discusses the different noise-cancellation techniques used in headphones and earphones.

What is Noise Cancellation?

In simple terms, noise cancellation removes or suppresses unwanted sound from an incoming stream of sound waves. This can be achieved using various methods.

At a larger scale, noise can be canceled using double-paned windows and soundproofing materials.

Similarly, on a smaller scale, such as in headphones or earphones, noise cancellation is achieved through soft padding that provide a closed ceiling, electronic components, or a combination of both.

These headphones and earphones use additional microphones to capture ambient/external noise, which is then analyzed and used to produce anti-noise with reversed polarity.

When this anti-noise is played through the headphone speakers, it cancels out the original noise, leaving behind the desired sound.

In many modern headphones and earphones, there are small holes, which may or may not be for a microphone.

Interested in knowing more about these mysterious holes?

I have written a small post about👉 the functionality of small holes in earphones.

Introducing ANC

The introduction of ANC technology significantly upgraded noise-canceling technology in headphones and earphones.

ANC is an effective noise-cancellation technique widely used in noise-canceling headphones and earphones.

Note that noise-cancellation is an umbrella term. In addition to ANC, there are also other types of noise cancellations.

Types of Noise Cancelation and Their Working

Active Noise Cancellation (ANC) – How does ANC work?

ANC, short for Active Noise Control/Cancellation, is an advanced audio technology that uses microphones to capture external noise and generate inverted sound waves of the captured noise through the headphone speakers to remove background noise.

The newly generated inverted sound wave is called anti-noise, which is used to cancel out the incoming ambient noise through destructive interference.

Unfortunately, ANC is not a complete solution to noise cancellation as it can only cancel out noise from a constant source.

Noise-canceling headphones work best in airplanes, trains, buses, offices, or anywhere with constant ambient noise.

If you are exposed to non-uniform sources of noise like a child screaming, vehicle horns, etc., you will be able to hear some parts of it, even with ANC earphones or headphones.

But again, the amount of noise cancellation varies in each headphone, and they all don’t work the same way.

Some expensive ANC-integrated noise-canceling headphones have different settings or modes that allow you to adjust the amount and quality of noise suppression.

There are primarily three types of ANC. The only difference is how they capture and process the surrounding noise.

1. Feedforward ANC

Feedforward ANC is the most used ANC technique. In a feedforward ANC configuration, the outside noise is captured using an external microphone and fed to the ANC processor.

The processor then generates an anti-noise and sends it to the speaker along with the audio one was listening to.

Here we anticipate an effect and program the processor to counter that, so the chances of errors are high.

2. Feedback ANC

Feedback ANC uses a microphone in front of a headphone speaker to record the feedback sample of what a user hears.

Using this feedback as a reference, Feedback ANC adapts to the noise you hear.

Here we analyze the effect in real time and use that data to counter noise accordingly.

3. Hybrid ANC

Hybrid ANC is a combination of both feedforward and feedback ANC. It employs two microphones to analyze the noise.

One microphone is in front of the speaker to record the feedback of what the user hears, and another mic is on the headphone’s body facing outward to capture external noise.

The ANC processor uses input data from both these microphones to cancel noise with higher accuracy.

Hybrid ANC is rarely used in noise-canceling headphones, but some high-end manufacturers use it on their headphones to give better performance to the user.

Passive Noise Cancellation (PNC)

Passive Noise Cancellation (PNC) is when you close your ear canal with an earplug, finger, or something of sort that physically shields the outside noise from pushing into your eardrums.

Since it can only passively cancel out the noise, it’s called passive noise cancelation.

Here external noise is shielded from reaching your ear with closed-back headphones that provide good sealing or clamping around your ear.

Headphones with tight sealing around your ear will, by default, provide some form of physical isolation from external noise. Headphones with soft padding generally are very good at this.

Adaptive Noise Cancellation

Adaptive noise cancellation is a technique wherein the surrounding noise is observed in real time to cancel out the noise effectively.

It is also known as Pure ANC, as it filters out most of the external noise. Adaptive noise cancellation is the best noise-canceling technique, but it’s rarely used.

Is Noise-canceling Feature Worth it?

Advantages

Some of the advantages of using noise-canceling headphones include

• Reduced fatigue
• Improved concentration
• Increased productivity
• Reduced stress
• Great at blocking monotonous sounds

Disadvantages

Some disadvantage of noise-canceling headphones is that

• In most cases, the sound you hear won’t be as crisp as regular headphones or earphones.
• It could reduce the sound quality if there is no noise to cancel.
• Most noise-canceling headphones will have a strong clamp force causing pain around the jaw and ear.
• Noise-canceling headphones are power-intensive, so it require a good battery backup.

Final Thoughts

Though noise-canceling headphones and earphones are not a total solution to noise cancellation, they offer a significant advantage over their generic counterparts.

All headphones and earphones won’t react similarly to noise. Instead, each will have its limitations and advantages depending on its design and integrated technology.

To know more about what to look for in a headphone, check out our headphone selection guide.

Frequently Asked Questions

Does noise-canceling hurt ears?

No, noise-canceling doesn’t hurt your ears. When you initially start using noise-canceling headphones or earphones, you may hear a slight buzzing sound, but you’ll get used to it eventually. If something is hurting your ear while using headphones, it might be because of the pressure it applies to your ear.

What is CVC noise cancellation?

In audio, CVC is shot for Clear Voice Capture. It is a software-based technology that suppresses and filters background noise to capture a person’s voice. CVC technology is mainly used in two-way communication devices like cell phones.

What are anti-noise and anti-sound?

Anti-noise is an inverted audio signal of background noise. It is used to filter out noise from an audio output. Anti-sound is a sound produced by the speaker once it receives an anti-noise signal.