Noise-cancelling headphones on the market can be wireless noise cancelling earbuds divided into active noise-cancelling and passive noise-cancelling.
Passive Noise Cancelling Headphones
The main purpose is to isolate the external environment noise from the ear by using the physical structure characteristics, and prevent the noise from entering the ear by analyzing the obstructions of different product materials, just like setting off firecrackers to cover the ears with hands.
Very effective against high frequency noise. Noise can generally be reduced by about 15-20dB. This method of noise cancellation is the most traditional and common, and offers the lowest price compared to active noise cancelling headphones.
The noise reduction space is large. Passive noise reduction has a good isolation effect on high-frequency signals, and has a large noise reduction space. Such as sound insulation panels beside the road. However, for low frequency noise in small spaces, noise such as air conditioner operation noise, aircraft engine noise, etc., is greatly reduced in effect.
I can't remove the noise. Most of the portable noise-cancelling headphones we've seen are passive noise-cancelling, with built-in earbuds and headphones providing some degree of isolation, but there's no way to neutralize the noise for quiet listening.
The tone is too loud. In order to improve the noise reduction effect, many passive noise-cancelling headphones increase the original sound to eliminate noise, which is not good for ear health, which requires everyone to carefully check and compare the pitch of noise-cancelling headphones.
Active Noise Cancelling Headphones
The theoretical development of active noise-cancelling headphones is very simple. All sounds are composed of a certain frequency spectrum. If companies can find such a Chinese sound, its frequency spectrum is completely different from the noise data to be eliminated, but the phase Just the opposite (a difference of 180°), this noise can be completely canceled. Active noise reduction methods use digital signal processing (DSP) to eliminate noise from the outside world. This kind of educational technology management is to build a system miniature microphone in the headset and for an acoustic processor, when there is noise around, active noise reduction will need to create a completely opposite sound belonging to a country through the network processor. and cancellation, which is called "destructive interference" in acoustics.
The sound quality is pure and beautiful. Active noise reduction makes up for the lack of passive noise reduction in low-frequency noise reduction, bringing users a purer and more beautiful sound quality. For example, the noise of public places, the rumble of cars and trains, is more suitable for the user's scene.
to protect the user's hearing. Active Noise Cancellers are equipped with dedicated noise cancellation circuitry, including custom high-sensitivity mems silicon microphones and professional-grade noise cancellation chips, which cancel noise by receiving and analyzing external noise spectrum and generating signals of opposite phase. Why did you say that? We assume that the ambient noise (in decibels) is constant, and the volume of the mobile phone that can meet the hearing needs without noise-cancelling headphones is 20 bars, while the noise-cancelling headphones only need 10 bars to meet the hearing needs. So from this point of view, noise-cancelling headphones for hearing protection stand out.
high cost. However, the equipment required for an active noise reduction system is the pickup, processing wafer, loudspeaker, and each part is guaranteed to be of high quality to achieve the final effect, so the cost is high.
energy consumption. Active Noise Cancelling headphones are an acoustic processor, so turning on Active Noise Cancelling mode can adversely affect the durability of wireless headphones.