How Does Noise Cancelling Work?

What is Noise-Cancelling Technology?

Noise-cancelling technology, also recognized as active noise cancelling (ANC), works by getting rid of or lessening undesired background noise through the creation of sound waves that counteract ambient input.

Shubham Munde, a tech research analyst at the global market analysis firm Market Research Future, explained that noise-cancelling technology generates a sound wave precisely 180 degrees out of phase with the captured sound. This opposing wave effectively cancels out the original sound, leading to an overall decrease in the surrounding noise level.

This "anti-sound wave" is then transmitted through a speaker or headphones, synchronized with the audio content a user is enjoying, like a song or podcast. Munde, an information and communication technology domain expert, likens this process to a mathematical equation where a positive integer nullifies a negative one, leaving the desired audio content for the listener.

For example, Craig Fraser, CEO at audio equipment manufacturer BEACN, illustrates how noise-cancelling headphones can be beneficial in a noisy coworking space during an online meeting. The headphones minimize or eliminate background noise, allowing the user to focus solely on the speaker's voice.

How Does Noise Cancelling Work?

Noise cancellation relies on a phenomenon known as phase cancellation. To negate a sound wave, an opposing sound wave is generated in an identical but opposite form. This involves matching each peak, valley, compression, and rarefaction of an incoming audio wavelength with its inverted version at the same amplitude.

Typically, noise cancellation employs a system of small microphones situated inside and outside a device that detects ambient sounds. Processors analyze these sounds and create counteractive sound waves through built-in speakers.

During a process termed destructive interference, the unwanted ambient input combines with an outbound signal in its inverse shape, forming a new wave. So, when a user listens to music or a podcast with active noise-cancelling headphones, they experience their chosen audio content playing over a customized anti-sound wave, adapted to their specific surroundings at any given moment.

Is Noise Cancellation Harmful to Your Ears?

To put it simply, no. There is no evidence indicating that noise-cancelling technology causes any negative effects for users.

However, it's important to acknowledge the discomfort reported by some users who experience vertigo or dizziness when using active noise-cancelling headphones. This can be attributed to the low-frequency signals that may trick the brain into perceiving motion. Another psychosomatic effect known as "eardrum suck" might cause unease similar to that experienced during a sudden change in altitude.

In terms of overall well-being, Amy Sarow, a doctor of audiology and lead audiologist at the online hearing-aid marketplace Soundly, emphasizes the importance of responsible headphone use, particularly regarding listening volume.

According to Sarow, "Noise-cancelling technology on its own does not cause hearing damage. However, hearing loss due to noise can occur when the listening volume exceeds a safe level." Both the U.S. Environmental Protection Agency and the World Health Organization recommend 70 decibels, akin to the sound of a dishwasher or a washer-dryer unit, as a safe threshold to prevent hearing loss. Sarow, who is also a member of the Forbes health advisory board, suggests maintaining the volume at 70 percent of the maximum sound bar when using headphones.

Fortunately, Sarow adds that noise-cancelling technology facilitates listening at a safe level, as users don't need to raise the volume above the background noise.

Conclusion

In the realm of noise-canceling, silence is not merely the absence of sound; it's a carefully orchestrated symphony of anti-noise. The next time you put on those noise-canceling headphones, remember that you're not just escaping the noise—you're embracing the marvel of technology that turns chaos into calm.