Active noise reduction: what is it?

Active noise reduction (ANC) is a feature of headphones and listeners mid- to high-end wireless that uses what’s called “signal processing” to block out outside sounds. Many of our helmets favorites provide this feature. To put it simply, the ANC function goes a step further than earplugs by ensuring that the majority of distracting and constant noise will be filtered out. The system is not completely transparentso if you turn on headphones with ANC, you’ll hear it working in the form of a subtle hiss.

How does active noise reduction work?

The noise reduction active works through a series of microphones placed strategically around headphones or earphones and a concept known as phase cancellation. The first step is to use these microphones to determine what the listener is hearing.

Once the microphones have captured this his, the digital signal processing hardware and software inside the headset get to work. This is where things get complex.

You’ve probably heard the term ” sound wave “. That’s what a sound is: a series of vibrations in L’air. If you take a sound, play it back, and then delay it slightly, the waves are no longer aligned. The peak of one waveform occurs at the same time as a peak in the opposite direction of the other waveform, so they effectively cancel each other out.

This rarely happens in nature and therefore looks unnatural, but this method still works. Headset microphones use exactly this technique. Some headsets use a rather crude implementation, while others use advanced hardware and software to intelligently adapt to your environment.

Some headsets use externally placed microphones. It’s easier to do, especially on earbuds, but it’s not the most efficient method because it doesn’t accurately reflect what you’re hearing.

Larger headsets may use microphones placed inside the ear cup. This means the sound canceled by the headset more accurately reflects what you hear, making cancellation more effective. Finally, other headsets take a more expensive approach and position the microphones inside and outside of the headset, allowing for complete noise cancellation.