Active Noise Cancellation is Not for Outdoor Sports

In my opinion (which is likely to be controversial), Active Noise Cancellation (ANC) has no place in earbuds or headphones intended for outdoor sports. This includes running, cycling, and pretty much any outdoor activity.

ANC is a technology whereby earbuds and headphones attempt to subtract outside sounds from entering the listener’s ears, creating a quiet soundscape in an noisy environment. This creates some peaceful auditory isolation and solitude. It also lowers the noise floor so that music can be enjoyed more clearly, potentially at lower volumes. It’s great when it works.

ANC uses external microphones on the device, producing an electrical signal of the outside noises. Then that signal is subtracted (quite literally) from the signal powering the drivers inside the device aimed at the listener’s ears.

Microphones, no matter how good, have a weakness: wind noise. Air currents passing over an object create eddies and turbulent swirls of air pressure. The faster the air flow, the stronger and more turbulent the eddies are. The purpose of a microphone is to detect tiny changes in air pressure and convert them to an electrical signal. Therefore, microphones are very sensitive to even the tiniest air turbulence, especially when it is right on the microphone. The result is a noise, captured electrically, known simply as wind noise. Actual air turbulence isn’t very loud, especially when your ears are stopped up with earbuds or covered by headphones. However, the microphone captures it as a loud signal.

When earbuds or headphones with ANC capture wind noise, they attempt to subtract that noise through the device’s driver. However, since no such noise exists inside the listener’s ear, ANC ends up creating a negative or inverse version of the wind noise and playing it into the listener’s ear. To the listener’s ear, a negative wind noise signal sounds just the same as a positive signal, and it is heard as noise. Noise that is loud and competes with the music or audio that the listener is trying to hear.

It takes very little wind to create this problem. 3 or 4 mph? Simply standing in place on a lightly breezy day will cause ANC earbuds to make wind noise. Running or even a brisk walk through still air will have this problem. You can forget about using ANC earbuds while cycling.

The same problem occurs even worse with “transparency” or “hear-through” modes, since the outside sounds are reproduced by the device’s driver at an even louder volume.

Incidentally, wind noise is also a problem when trying to have a phone conversation. The wind noise will be sent to the person on the other end of the phone conversation, often overpowering the earbud user’s voice.

People using ANC earbuds or headphones for outdoor activities will want to turn off both ANC and transparency. When buying earbuds specifically for running or outdoor sports, it is better to look for products that do not have ANC. At the very least, it must be possible to turn off ANC and transparency. Not all earbuds have this capability.

Manufacturers don’t seem to care about this problem. That’s because buyers of earbuds are mostly not aware of the problem, and manufacturers know it is difficult to compete in this space without having ANC.