Technological innovation

Do you know how ANC works?

With the development of modern industry, environmental pollution has also arisen. Noise pollution is a type of environmental pollution and has become a major hazard to humans. Therefore, various noise reduction technologies have emerged. Airplanes, ships, and even high-end cars have already applied active noise reduction technology to make us feel more comfortable when riding in transportation. As a personal consumer product headset, ANC active noise reduction technology is even more important.

ANC active noise reduction is simply a kind of "lightweight" and "active" technology. Starting from the noise propagation characteristics, the use of "reciprocal" superimposed offset, reduces the noise intensity.

Q1:What is active noise reduction?

ANC active noise reduction is simply a kind of "lightweight" and "active" technology. Starting from the noise propagation characteristics, the use of "reciprocal" superimposed offset, reduces the noise intensity.

Q2:Since there is active noise reduction, and passive noise reduction?

Passive noise reduction is to block the noise through physical shielding to reduce the impact of sound on the ears. However, generally speaking, the use of masking or airtight methods has a good isolation effect on high-frequency noise. For low-frequency noise in a small space, noises such as air conditioning noise and aircraft engine noise are not very effective.

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There are two main ways to apply passive noise reduction in headphones: sealing and shock absorption. Sealing refers to whether there are air holes in the earphone cavity and the thickness of the cavity. Generally, in-ear earplugs or comfortable memory foam earmuffs are used to achieve passive noise reduction.

It sounds complicated, but it's actually the same as covering your ears with your hands, but using headphones instead of your hands.

Q3:What are the principles and advantages of active noise reduction?

The principle of active noise reduction is actually very simple. We have all learned it in middle school physics classes. Don't tell Xiao Zhen that your physics class is also taught by a physical education teacher.

Sound is a wave, it has crests and troughs, both of which directly determine the size of the sound. For example, the picture below vividly describes the characteristics of "wave".

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The ANC noise reduction technology is to analyze the sound waves of the noise, and then superimpose and neutralize the sound waves by sending the reverse sound waves to achieve the effect of eliminating the noise.

According to physics theory, when two waves of the same frequency and opposite phase meet, interference and superposition will occur. Therefore, as long as a similar wave with completely opposite states is designed, the intensity can be minimized and the noise can be eliminated.

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For example, when an object vibrates upward under a force, another force takes the initiative to suppress the vibration and let it stay in place. Active noise reduction technology is achieved in this way, allowing one sound wave to suppress another sound wave.

Q4:What is the logic of ANC active noise reduction?

Pickup (monitoring environmental noise) → processing chip (analyzing noise curve) → speaker (generating reverberating sound waves) → completing the process of noise reduction synthesis.

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Simply speaking, assuming that the noise that appears is A, after being detected by an external pickup, a sound of -A will be generated instantly, and the two will cancel each other out in the ear to achieve the function of noise reduction. It can be said that your ears have "heared" the noise, but at the same time you have also heard "noise reduction". The two cancel each other out in your ears to achieve noise reduction.

Q5:ANC active noise reduction is so powerful,is there no need for passive noise reduction?

The answer is no.

ANC active noise reduction has latency. Its noise reduction principle is based on the calculation of existing noise. When next time the same noise comes, it will send out reverse sound waves to offset it. However, in an open environment, the surrounding environmental sound is not a simple waveform, and the vibration amplitude of each waveform is also different. The high-frequency sound waves are shorter and change faster, and sometimes they will be covered by the next sound wave before it is too late to predict.

At this time, we need to pass passive noise reduction to further block high-frequency noise. To achieve the effect of "the world is quiet", in addition to active noise reduction, passive noise reduction is also essential. The combination of the two allows users to feel the real "silence" when wearing earphones with only beautiful melody surrounding their ears.

Current main TWS bluetooth chipset with ANC function:

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