Noise, a word that is not unfamiliar.

It always appears in our lives from time to time.

Bring damage to the auditory system and beautiful mood.

It is the sound produced when an object vibrates irregularly, and it propagates in solid, liquid, and gas in the form of waves.

In addition to the familiar high-frequency noise that allows us to react quickly to cover our ears, the low-frequency noise that is easily overlooked is like a chronic poison that is "quietly" hurting us.

Low-frequency noise with a frequency below 500 Hz will continue to cause harm to people. It is not as harsh as sudden brakes and whistle sounds. Instead, it resonates with the frequency of low-frequency vibrations and noises close to our internal organs. It is low-frequency noise throughout the year. The heart, lung, spleen, kidney, liver, etc. will be irreversibly damaged under the influence.

The low-frequency sound you hear is usually between 125 Hz and 250 Hz. The low-frequency noise that makes you feel uncomfortable is mainly formed by the sound MR curve. It continues to disturb you through a frequency exceeding the peak. This low-frequency noise It is not easy to attenuate through distance or obstacles.

The high-frequency noise can be quickly attenuated as the distance is farther or obstacles are encountered. For example, a point source of high-frequency noise can drop by 6 decibels every 10 meters, and a linear sound source on the road can drop by 3 decibels every 10 meters, but the low-frequency noise decreases very slowly. Therefore, it can be worn over long distances. The wall goes through the wall and reaches the ear bones, which will make people's sympathetic nerves tense, and the heartbeat will speed up.

When people are forced to accept this kind of noise, they are easily upset, irritable, and even lose their minds. If you are disturbed by low-frequency noise for a long time, it is very easy to cause neurasthenia, insomnia, headache and other neurosis.

In our daily lives and workplaces, low-frequency noise is almost everywhere. Elevators, water pumps, power distribution rooms, transformers, generators, cooling towers, compressor rooms, and even home air conditioners, refrigerators, computers, fish tanks, as long as they are in working condition, are constantly making a "buzzing" sound.

Low-frequency noise is the most harmful to us and the most difficult to avoid. The principle of active noise reduction is simple, but there are many technical difficulties, especially the phase of the destructive mechanical wave must be accurate, otherwise it will be counterproductive. Active noise reduction headphones use the noise reduction system to generate reverse sound waves equal to the external noise, neutralize the noise, and achieve the noise reduction effect:

1. The signal microphone placed in the headset detects low-frequency noise in the environment that the ear can hear

2. The noise signal is transmitted to the control circuit, and the control circuit performs real-time calculations

3. Use Hi-Fi speakers to play sound waves with the opposite phase and the same amplitude as the noise to cancel the noise

4. After superposition, the low frequency noise disappears, and the hearing is better protected

High-frequency noise can be eliminated to a large extent by passive noise reduction methods such as silicone sleeves or earmuffs, which complements the advantages of active noise reduction methods, and can reduce external noise to the greatest extent.

After the noise is isolated and reduced, the corresponding safety hazards also appear. Therefore, the active noise reduction headphones can not only turn on noise reduction, but also have a good offsetting effect on low-frequency noise. It can also turn on the monitoring mode to ensure travel safety.

When you are at a loss for noise and want to escape, put on noise-canceling headphones. You can also reduce unhealthy noise caused by vehicles on airplanes or trains that are full of low-frequency noise that is extremely harmful to humans. Reject noise and protect hearing. If you are afraid of noise, use noise-canceling headphones.