WHAT IS ANC AND HOW DOES IT WORK?

Written by Asha Kalsi 

ANC, also known as Active Noise Cancellation, is becoming an increasingly popular feature in headphones these days, no matter your budget. Like many of us, you may have seen headphones on the market with ANC listed as one of their features and you might be wondering what it actually is and how it works. Let's break it down! 

For starters, what does ANC stand for and what does it do? 

ANC or Active Noise Cancellation is a technology designed to actively cancel out background noise, enhancing your listening experience. You may already be familiar with noise isolation or passive noise cancelling, which uses sound-proof materials to create a seal around your ears. It is designed to muffle outside sounds but sometimes it might not quite cut it for letting you enjoy your music without outside distractions.  

Active noise cancelling takes this further by employing microphones to detect and counteract external noise within the headphones themselves. This allows the external sound waves to be neutralised by an inverted version of those sound waves. Some higher-end models employ Digital Signal Processing (DSP) which enhances these effects by analysing the surrounding noise and generating an adaptive anti-noise signal. 

How does ANC technology work? 

To understand how ANC functions, it's essential to grasp the fundamentals of how we hear. When sound reaches our ears, it travels in the form of sound waves that vibrate the tiny hairs inside the cochlea of the inner ear. These vibrating hairs send signals to our brains, allowing us to perceive sound. 

ANC technology makes use of these principles by using small and sensitive microphones to detect the sound waves present in our environment. Without ANC, these waves would reach our ears and potentially disrupt our listening experience. However, ANC steps in to neutralise these environmental sounds. It does this by producing sound waves that are the inverse of the detected waves, effectively cancelling them out. Think of it as a mirror image of those original sound waves. A term for this phenomenon you might find while researching ANC headphones is destructive interference. While there might still be some faint ambient sounds remaining, they should be significantly dampened, enabling you to focus on the audio you're listening to. 

ANC particularly excels at reducing lower frequencies of noise. This is because lower frequencies have longer wavelengths and are more predictable. As a result, ANC headphones tend to be consistently reliable when tackling lower frequency environmental noise across all price points. 

The ideal range of ANC effectiveness can vary among different brands. However, the industry standard typically falls within 15 to 30 decibels. It's important to note that factors such as the number and types of microphones, algorithms can differ across brands and price ranges, which can impact the overall performance of ANC headphones. 

ANC comes in different forms which affect its performance 

One crucial aspect of ANC is the placement of microphones, which varies across different types of ANC systems. 

Feedforward ANC is an implementation where the ANC microphones are positioned on the outside of the headphones or earbuds. These microphones detect the ambient or background noise before it reaches your ears. By capturing the sound outside the listening device, feedforward ANC can effectively analyse and process the noise to generate an anti-noise signal that cancels out the unwanted sounds. 

Feedback ANC, on the other hand, involves placing the microphones inside the headphones, right in front of the speaker drivers. Speaker drivers are components responsible for converting electrical signals into audible sound. By placing the microphones in close proximity to the speaker drivers, feedback ANC captures the audio signal that is about to be emitted and cancels any discrepancies or noise that might be present. This placement allows for more precise noise cancellation since the microphones are positioned near your ears. 

In order to maximize the benefits of both feedforward and feedback ANC, a combination called hybrid ANC is often used. Hybrid ANC incorporates the advantages of both placements to cover a broader range of frequencies and minimize the possibility of background noise leaking through. This approach aims to provide comprehensive noise cancellation across various sound frequencies, resulting in an enhanced listening experience with minimal disruptions. 

So, do I actually need headphones with ANC? 

When considering if it's worth investing that little bit extra on headphones with ANC, you may want to keep in mind the kinds of environments they really shine in. Initially, ANC was developed to protect the hearing of pilots; the technology thrives in environments where you have a lot of intrusive or even potentially harmful background noise but can be just as useful in blocking out irritating or distracting background noise. Whether it's the workplace, a manufacturing facility, or even during travel on buses and trains, noise-cancelling headphones prove invaluable in minimising distractions and allow you to focus on your tasks or enjoy your journeys without unnecessary noise interference. For those susceptible to focus or sensory overload issues, ANC can be a serious game-changer in keeping distractions at bay. It can also be a great feature for those of us who find ourselves turning the music up and up to unsafe levels. ANC acts as a great feature to help protect your hearing while still enjoying the music you love by allowing the music to take center stage without any outside noise muddying it. If you find yourself wishing you could block out the world with your headphones, ANC is a great feature you'll love. 

What about the side effects? Does it damage hearing? 

When it comes to the potential side effects of ANC, particularly regarding hearing damage, it's important to understand that ANC technology itself is not inherently harmful to your ears. Because it reduces the need to raise the volume of your audio to overcome background noise, ANC allows you to enjoy your music or audio content at lower, safer volumes. 

However, there are a few considerations to keep in mind. Using ANC headphones at excessively high volumes for prolonged periods of time can still be damaging to your hearing as it only cancels background noise. It's essential to exercise responsible listening habits and ensure that you don't expose your ears to excessive noise levels, even with ANC activated. 

Additionally, some individuals may experience a phenomenon known as "eardrum suck" or a feeling of pressure in the ears when using ANC headphones. This sensation is caused by the rapid changes in air pressure resulting from ANC's cancellation of external sound waves. While this sensation is generally harmless and temporary, it's advisable to consult with a healthcare professional if you find it uncomfortable or have any concerns. 

So, what can we take away from this information? 

Understanding how ANC works, including how it uses microphones, sound wave cancellation, and different placement techniques, helps us appreciate the technology's effectiveness and versatility alongside having the essential knowledge to choose the right headphones for your needs. Whether it's feedforward, feedback, or hybrid ANC, each approach allows you to create a personalised and optimised listening environment for yourself.  

Because ANC is an effective means of immersing yourself in your audio content without unnecessary distractions, it can be a great feature to consider when buying headphones. Whether you're a music enthusiast, a frequent traveller, or someone seeking a focused work environment, ANC can elevate your listening experience and provide a more immersive and enjoyable environment. For more, take a look at the Mixx range of ANC headphones and discover the joy of uninterrupted sound.