What does passive noise reduction mean?

Passive noise reduction, also known as "physical noise reduction", refers to the use of physical characteristics to isolate external noise from the ears, mainly through the design of the headband of the earphones to be tighter, the acoustic optimization of the earmuff cavity, and the Sound-absorbing materials are placed inside the cover to achieve physical sound isolation of the headphones. Passive noise reduction is very effective in isolating high-frequency sounds (such as human voices) and can generally reduce noise by about 15-20dB.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

The noise reduction function is very important for headphones. First, it reduces noise and avoids over-amplification of the volume, thereby reducing damage to the ears. The second is to filter noise to improve sound quality and call quality. Noise reduction can be divided into passive noise reduction and active noise reduction.

Passive noise reduction

Passive noise reduction is also physical noise reduction. Passive noise reduction refers to the use of physical properties to isolate external noise from the ears, mainly through the use of headphones. The headband is designed to be tighter, the earmuff cavity is acoustically optimized, sound-absorbing materials are placed inside the earmuffs, etc. to achieve physical sound isolation of the headphones. Passive noise reduction is very effective in isolating high-frequency sounds (such as human voices) and can generally reduce noise by about 15-20dB.

Active Noise Cancellation

The active noise reduction function uses the noise reduction system to generate reverse-phase sound waves that are equal to the external noise. Noise neutralization, thereby achieving noise reduction effect. Its principle is that all sounds are composed of a certain spectrum. If you can find a sound whose spectrum is exactly the same as the noise to be eliminated, but the phase is exactly opposite, the noise can be completely canceled out.

The difference between passive noise reduction and active noise reduction

1. Different noise reduction principles

Passive noise reduction is to fill the ear cup with sponge. To isolate noise through ear cups and sponges, there are certain requirements for the clamping force of the ear cups. If the clamping force is small and there is a gap between the ear cups and the ears, the noise reduction effect will be much worse.

Active noise reduction is to install an intelligent noise reduction chip in the ear cup. When the built-in sound pickup sensor of the earphones senses external noise, the intelligent circuit will generate a sound wave that is opposite to the external noise to offset it. noise.

2. Different prices

Passive noise reduction is simple to make and relatively cheap. You can usually buy it for tens of yuan to one or two hundred yuan.

Active noise reduction headphones have high technical requirements and the price is generally more than a thousand yuan.

3. Different applications

Passive noise reduction headphones can be used as labor protection headphones in factories, construction sites and other places. It is difficult to communicate with the people next to you when wearing noise-cancelling headphones at work. Active noise reduction headphones can not only shield loud noises, but also detect small sounds without affecting communication. They are generally used in noisy situations where external sounds need to be heard clearly.

Which sound insulation effect is better

Active noise reduction is better. If your requirements for noise reduction are relatively high, you should buy active noise reduction. If your requirements are relatively low, you can buy passive noise reduction. Active noise reduction headphones include active noise reduction and passive noise reduction, while passive noise reduction headphones only have the passive noise reduction part.

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