What are the dangers of noise to people? Does wearing noise cancelling headphones work?

The principle of active noise cancelling headphones is that their noise cancellation system emits sound waves that are opposite to the outside world to neutralize the noise, so as to achieve the effect of noise cancellation. Most people know this very well, but active noise cancelling headphones are not a panacea, they can't remove all the noise from the outside world. So, do active noise cancelling headphones do something about that outside noise?

At the technical level, active noise cancelling headphones are mainly based on the waveform of external noise, and then emit the opposite waveform to cancel it out, which is called "destructive interference" in acoustics. However, this only has an effect on the noise of the low-frequency stable waveform. Active noise cancelling headphones can't do anything about unstable, fast-changing waveform noise.

High-frequency noise is a short waveform that changes quickly, and sometimes ANC headphones are accepted by the ear before they can react.

In terms of user safety, active noise cancelling headphones are ineffective against high-frequency harsh sounds, which is also for the safety and convenience of users. If it is full-range noise cancellation, then it is undoubtedly dangerous to not be able to hear any sound outside after wearing headphones. For example, if you are walking down the road with headphones on, you can't hear a car horn, someone is talking to you, and so on.

Such a scenario does not meet the actual requirements of users.

The frequency that can be heard by the human ear is 20Hz-20kHz, and the frequency range of the human voice is 100Hz-8kHz, and the frequency of the car's horn, fierce knocking, and impact will be higher. Nowadays, the noise cancellation frequency of similar noise-cancelling headphones on the market is 100Hz-1kHz. As a result, the car's honk, its fierce knocking, the frequency of the impact, and the frequency of most vocals are ineffective.

Of course, most of the ambient and vehicle noise (engine and ground friction) is in the range of 100Hz-1kHz, so the effectiveness of ANC headphones for these noise cancellations is obvious.

Noise can harm the nervous system, cardiovascular system ......However, the most direct damage is to the auditory system. Strong noise waves can directly rupture the eardrum, hemorrhage, destruction of the ossicle bone in the middle ear, bleeding in the inner ear tissue, and explosive deafness. Long-term work in a noisy working environment will produce noise-induced deafness, significant hearing loss, and hearing damage.

Therefore, in appropriate circumstances, you can choose to wear noise-canceling headphones to prevent it.

Brand model: Huawei P50 Pocket System: HarmonyOS 3

Headphone active noise cancellation is harmful to the human body. After long-term use, it will lead to chronic damage to the auditory nerve, and some patients will have intermittent tinnitus symptoms in the early stage, and persistent tinnitus for a long time, followed by hearing loss.

Active noise cancellation for headphones is a noise reduction technology and is one of the methods applied to noise reduction in headphones. The active noise cancellation function is to neutralize the noise by generating a reverse sound wave equal to the external noise through the noise reduction system, so as to achieve the effect of noise reduction. The principle is that all sounds are made up of a certain frequency spectrum, and if you can find a sound, its spectrum is exactly the same as the noise to be eliminated, but the phase is just opposite to cancel the noise completely.