You must understand the four points that are the m

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If you want to buy real noise reduction earphones, you must understand the four points of

fast-paced life and work, which makes us busy. The increasing noise pollution in cities makes many people yearn to find their own "pure land"

if life and work are difficult to change; So, there are many ways to avoid noise. Among them, noise reduction earphone is a good solution

noise reduction earphones can be divided into two categories: active noise reduction and passive noise reduction. Because the two types of noise reduction methods have different principles, their noise reduction effects are not the same before the fire burns to the cabin. So what should we know and pay attention to when choosing

mechanical wave can be divided into the following parts according to the recognition degree of human ear: A. audible sound; b. Music; c. Talk. The figure below shows the visible audio and sound pressure. The focus of noise reduction is to eliminate the sound in the yellow area

the sound wave generated by the vibration of the object propagates around, and the sound energy gradually diffuses. The energy diffusion reduces the energy per unit area, and the sound heard last week becomes weak. The sound energy per unit area decreases with the square of the sound source distance

when sound waves propagate in a solid medium, the viscosity of the medium causes internal friction between particles, thus converting part of the sound energy into heat energy

at the same time, due to the heat conduction of the medium, the dense and sparse parts of the medium exchange heat, resulting in the loss of sound energy, which is the phenomenon of medium absorption

the attenuation of sound waves caused by the presence of granular structures in the medium (such as suspended particles and bubbles in liquid, granular structures, defects and impurities in solid, etc.) is called scattering attenuation

it is generally believed that when the particle size is much smaller than the wavelength, the scattering attenuation is proportional to the fourth power of the frequency; When the particle size is close to the wavelength, the scattering attenuation is proportional to the square of the frequency

in order to actively eliminate noise, earphone manufacturers have invented the technology of "active noise elimination". Its principle is that all the sounds heard are sound waves and have a certain spectral composition

if a sound wave can be found, its spectrum is equal to the noise amplitude to be eliminated, and the phase is just opposite. The superposition of the two can completely cancel the noise. This is also an important technology for active noise reduction

active noise reduction earphones generate reverse sound waves equal to the external noise through the noise reduction system to neutralize the noise, so as to achieve the effect of noise reduction

it is equipped with noise reduction circuits to compete with external noise. Most of them adopt large head mounted design, which can use earplug cotton and earphone shell to block external noise and carry out the first round of sound insulation. At the same time, it is also necessary to install active noise reduction circuits and power sources in order to have sufficient space

passive noise reduction earphones mainly form an enclosed space by surrounding the ear with earphones, or use sound insulation materials such as silicone earplugs to block external noise

for most manufacturers, a well-designed silicone earplug or thick earmuff can reduce high-frequency noise

first select the type of earphones you want to wear, which are commonly divided into in ear, ear pressing, ear wrapping, etc. Each type of earphone has a corresponding noise reduction function. It is assumed that all earphones fully meet the mechanical standard for pipe inspection. The parameters are the same. Regardless of objective reasons, the ear muff noise reduction earphone has the best effect

as mentioned above, active noise reduction earphones use a combination of active and passive methods in noise elimination, so they are far better than passive noise reduction

generally, noise reduction earphones will be marked with noise reduction as their selling point in product publicity. In addition, the product model will have the English abbreviation "NC" for noise canceling. Or in the parameter table, the noise reduction effect will be marked. 3. Automatic calibration: the system can automatically calibrate the indication accuracy; Bay number

in addition to speakers, the noise reduction system of headphones also needs power supply. Therefore, the endurance and charging capacity of noise reduction earphones are considered accordingly

refer to battery capacity, charging mode, endurance time under different use conditions, etc. Or select a headset directly connected to the decoder or playback device

unlike passive noise reduction, active noise reduction requires sophisticated technology. Therefore, in terms of brand selection, we recommend some large international manufacturers, such as Bose, Sony, beats, AKG, b o, etc

when searching for "noise reduction earphones", you will see a large number of earphones with the label of "noise reduction", and some of them will try to confuse consumers by describing ordinary in ear earphones (passive noise reduction) as noise reduction earphones

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