Active and passive noise reduction. Test on the street, in transport

Under what conditions can a headphone owner need active noise cancellation? How well does passive perform? How are these technologies implemented in modern microphones? Let’s find out.

Active Noise Cancellation

Everyone wants to enjoy music without being distracted by extraneous sounds. On a plane, you want to forget about the conversations of other passengers and the screams of children. On the street, you need to muffle the noise of cars and public transport. Even in the office, sometimes you want to get away from other workers.

Noise reduction helps with all this. And if previously it was exclusively passive, implemented through ear pads, now there is also an active one. It consists of delivering sounds in antiphase to surrounding noise. The operating principle of the technology is as simple as possible, although it requires a special chip in the device:

  1. External sounds are picked up by one or more headphone microphones.
  2. The noise is transferred to the processor.
  3. The chip digitizes received sounds by simultaneously reading the frequency and wavelength of the sound.
  4. The processor sends a wave of the same length and frequency to the ear, but “inverted” – antiphase.

As a result, one wave cancels out the other. If a particular track is not playing in the headphones at this moment, a person gets a feeling of silence. Now active noise cancellation (ANC) is available even to owners of relatively inexpensive TWS headphones. In some of them, extraneous sounds still reach the ears, in others you can achieve complete silence. As an example, let’s test realme Buds Air Pro – two years ago it was one of the most affordable models with ANC and transparency function. How do headphones perform in different conditions?

The accessory performs best in the park . It’s already quite quiet here. You can only hear something through music playing at a medium volume level when you walk past a sports ground where a lot of people are exercising. Their screams can be faintly heard.

When going out onto a busy street, it becomes clear that ANC technology struggles mainly with uniform and low-pitched sounds. If a car rushes past you, you can still hear it. But not the engine, but the rustling of tires, and only when the car is already very close. It’s as if all electric cars are driving past you.

The situation is similar in public transport . You can hear a car passing quickly and the sound of doors opening. Loud screams from children can also reach your ears, especially if you are not listening to music at maximum volume. If you often travel in the subway, ground public transport and airplanes, you should buy more expensive headphones – in such conditions they do their job better.

Finally, the shopping center . Here the test ended perfectly – not a single extra sound made its way through the music. Something could only be heard when you were as close as possible to the department where they sold audio equipment. Headphones do a poor job of canceling out the highest frequencies produced by speakers at high volumes. A similar situation was observed near slot machines.

Passive Noise Cancellation

How are external sounds canceled out by headphones and other devices that do not have ANC technology? Passive method. This is most relevant for wired models – the 3.5 mm jack is not capable of delivering enough energy to operate the ANC function. However, some manufacturers solve this problem by installing a battery. In this case, the headphones simultaneously receive wired and wireless operating modes.

If your headphones don’t have active noise cancellation, you have to rely on ear pads. For an on-ear model, you need to make sure that they completely cover your ears. It’s not for nothing that only these headphones are used by e-sportsmen! They do not need to be distracted by the voices of their surrounding comrades – instead, they need to hear in time which direction the enemy is approaching from. In the case of TWS headphones, “plugs” are best at muffling external sounds. Especially those with foam ear pads.

How technology works in microphones

For some time now, the active noise reduction function has even begun to be implemented in microphones. It is available on desktop models used for game streaming and podcast recording, as well as some wireless lavaliers. Previously, owners of such devices had to rely solely on passive noise reduction. However, even now, foam rubber or fur wind protection will not be superfluous, especially if the sound is recorded outdoors. Indoors, a pop filter is often used. It makes the voice more pleasant and fights stray gusts of air when pronouncing hissing words.