Noise Canceling Technology Explained

We often hear the term noise-canceling used with headphones and earbuds. While the term is pretty straight forward – it cancels noise – however, there’s more to it than that. Here we explain how noise-canceling technology works and its kinds.

First, let’s talk about the simplest noise canceling method, passive noise cancellation. This works by physically blocking all outside noise by sealing your ears. In-ear monitors and over-ear headphones are good examples of these, as they completely cover either the ear canal or your whole ear. This particular type of noise cancellation is typically advised for users at home (or those who aren’t mobile), so they can focus on the sounds they want to hear without distractions or outside noise. However, for those that are commuting or need to be aware of their surroundings, using audio devices with passive noise cancellation is generally not recommended.

Active noise cancellation (or ANC) is the second kind of noise-canceling technology and is a lot more complicated than the first kind. It was first invented by Dr. Lawrene Fogel for aviation back in the 50s. As you can imagine, aircraft engines are loud. So loud, that it makes communication between two pilots almost impossible. To combat this, Dr. Fogel theorized that by playing back the sound waves with the same wavelength but opposite amplitude, the sound cancels out. Active noise cancellation requires mics and an ANC controller as well, to record the ambient sound frequencies and reverse for the audio device to play back. The science behind active noise cancellation has a few inherent limitations, such as:

• The sound being canceled out must be continuous, such as the sound from an engine. Sudden or unexpected sounds from speech, random car horns, and such will not be canceled out and might even distort the sound your listening to once the reverse frequency is played back.
• Mic quality affects how well noise is canceled out. If the mics used are unable to accurately capture the frequency of the ambient noise from the outside, then the reverse frequency will not be able to negate the noise.
• Lastly, mic placement also plays a significant role in its efficacy. The sounds outside your listening device (say outside the ear cup or IEM) is different from the sound you’ll be hearing when wearing one. Hence, placing the mic outside the earcup or bud won’t completely block out noise. The opposite, however, isn’t ideal either, as it will pick up the sound coming from your audio device. A combination of the two would be more effective, and some audio devices have mics both inside and outside. However, they’re more expensive and require more juice to power.

If you’re looking to go wireless, there are some choices with Active Noise Cancellation, like the Apple Airpods Pro, Sony WF-1000XM3, Xiaomi Mi Airpods Pro, and Huawei Freebuds 3.

And that’s noise-canceling technologies in a nutshell! Let us know in the comments what other terms and tech jargon you’d want to be explained.

With edits and updates by Alejandro Maquinto