With the improvement of living standards, people have higher and higher requirements for sound quality, and wireless noise-cancelling headphones have also emerged. Although wireless noise-canceling headphones are hyped, their noise-cancelling technology is not as effective as advertised.
The noise reduction technology of headphones can basically be divided into two methods, which can reduce unnecessary noise to reach your eardrum. One is passive noise cancellation technology. This name is a creative name that the marketing team came up with. It has no technical content. It is also called sound isolation, which essentially uses a physical barrier to prevent outside sounds from entering your ears. When you wear headphones or earplugs, its silicone head will block your ear canal, allowing only the sound in the headset to reach the eardrum, which is like a cork of red wine, which blocks the mouth of the bottle.
Passive noise reduction was born when humans began to learn to cover their ears. The real technological content is active noise reduction, which is also known as active noise cancellation technology. In 1932, active noise cancellation technology was born, but in the 1950s, it began to be used in pilots, it can use equipment to filter out unwanted noise.
The microphone outside the headset can collect noise from the surrounding environment, and then the device can perform Fourier transform on these noises to convert it from a time-domain signal to a frequency-domain signal. Finally, the device will identify the frequency of the noise based on the frequency domain signal, and then emit the opposite sound to cancel the noise. In simple and interesting language, active noise reduction is to make the headphones produce more noise to offset the noise in the environment.
Bringing active noise technology to wireless headsets is a bit sudden, and there are some technical difficulties, such as minimizing equipment, but this has become a selling point of wireless headsets. But is it really effective? It is effective, but the effect is not as many consumers imagine. If you are standing in the square with headphones on, you will not immediately feel that the world around you becomes quieter, nor will you feel like you are standing in an anechoic room.
The reality is that noise-canceling headphones can remove most of the low-frequency noise, but only a small part of the high-frequency noise. If you travel frequently and spend most of your time on an airplane, then noise-canceling headphones are worth the money for you because they can effectively eliminate the low-frequency noise caused by aircraft engines. Even if you are not listening to music, wearing headphones can also improve your flight experience.
Now, headset manufacturers are developing a new feature that allows you to listen to music while wearing headphones, while hearing what others say to you. This technology is just the opposite of active noise cancellation. It can filter the sound of your dialogue through artificial intelligence, and then play it in the headset. In this way, you don’t need to take off the headset when chatting with others.