This function is similar to the principle of noise-reducing headphones, but it is not bidirectional, that is to say, the noise-reducing effect will only be effective for the receiver, but not for the other party's voice in this machine, and it can only be realized after the other party's mobile phone is turned on for noise reduction;
Take iPhoneX as an example. There are four microphones hidden in the body of this mobile phone. The two holes at the bottom of the speaker near the charging port are actually two microphone openings. There is a microphone opening at the lower right of the back flash. There is a microphone hidden in Liu Haiping's earphone. Now it can filter unnecessary sounds when using the mobile phone, thanks to the joint work of four microphones.
According to the different working environment, the functions of the four microphones of iPhone X are actually different. For example, during a call, the system will automatically call the microphone at the bottom as the sending microphone, and the microphone next to the camera as the noise reduction microphone. The three microphones work together, so that the user's words can be clearly transmitted to the receiver of the other party, while most of the ambient sounds are filtered out.
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At present, smart phone products basically have noise reduction microphones. If the other party says it is too noisy during the call, it is basically that the noise reduction microphone is broken.
In order to achieve better noise reduction effect, mobile phone manufacturers usually separate the two microphones as far as possible, that is, one at the top and one at the bottom. When we are talking, the sound signals captured by the microphone close to the mouth and the microphone far away from the mouth are different, but the environmental sound signals are the same.