Describe the classification and principle of Bluetooth headset noise reduction

It is well known that when buying a Bluetooth headset, the sound quality of the headset is the most important thing. Whether it is a Bluetooth headset factory, a distributor or a user, they do not care about the sound quality of the Bluetooth headset. When it comes to the sound quality of the Bluetooth headset, you have to talk about the noise reduction function of the Bluetooth headset. , I must have stopped a lot of professional terms, what noise reduction functions such as CVC, DSP, etc., I am confused, and the more I listen, the more confused I am. Today, the Bluetooth headset factory will explain the noise reduction function of Bluetooth headsets in general to help you buy Bluetooth. earphone.

1. ANC noise reduction (Active Noise Control, active noise reduction)
Its working principle is that the microphone collects external environmental noise, and then the system transforms it into a reverse sound wave and adds it to the speaker. The final sound heard by the human ear is: environmental noise + reverse environmental noise, and the two noises are superimposed to achieve The sensory noise is reduced, and the person who benefits is yourself.

2. ENC (Environmental Noise Cancellation, environmental noise reduction technology)
This can effectively suppress 90% of the reverse environmental noise, thereby reducing the environmental noise up to 35dB or more, allowing gamers to communicate more freely. Through the dual-microphone array, it can accurately calculate the direction of the caller's speaking. While protecting the target voice in the main direction, it removes various interference noises in the environment, which benefits the other party of the call.

Three, DSP (digital signal processing)
This is mainly for high and low frequency noise. The working principle is that the microphone collects the external environment noise, and then the system replicates a reverse sound wave equal to the external environment noise to cancel the noise, so as to achieve a better noise reduction effect. The principle of DSP noise reduction is similar to ANC noise reduction. However, the forward and reverse noise of DSP noise reduction directly neutralizes and cancels each other within the system, and the benefit is yourself.

4. CVC (Clear Voice Capture)
This is the noise reduction technology of call software. Mainly for the echo generated during the call, through the duplex microphone noise cancellation software, it provides the echo of the call and the environmental noise cancellation function. It is the most advanced noise reduction technology in the Bluetooth call headset. Of course, the benefit will be the phone. Of her.

After understanding some professional terms, we will come to understand several functions and principles of noise reduction in general.

1. Passive noise reduction.

This refers to in-ear earplugs, because the earplugs are inserted into the ear canal of the human ear through a silicone sleeve. Therefore, it has a better function of isolating external sounds. And this noise reduction is full frequency, that is, it is effective for sounds from 20 Hz to 20K Hz, and this passive noise reduction is lossless sound quality. So the general HiFi earplugs are in-ear type for this reason.

2. Call noise reduction.
Call noise reduction refers to the design of Bluetooth headsets for the caller to hear clearly. Common such as Qualcomm's CVC noise reduction. Its principle is to use the chip inside the Bluetooth headset to filter the signal received by the call microphone to reduce the external wind noise. At the same time, you can also perform echo reduction processing on the call sound from the other party.

CVC noise reduction does not have an additional microphone to collect external noise, so the noise reduction effect is still not enough for practical applications. Therefore, some Bluetooth headsets are also designed with additional microphones to collect environmental noise, and then the internal processor will subtract the external noise collected by the noise pickup microphone from the signal collected by the call microphone. Therefore, this noise reduction effect is much better. This kind of noise reduction is generally called "uplink noise reduction".

3. Active noise reduction.
Active noise reduction means that in some specific occasions, such as high-speed rail/aircraft, some regular noise from the outside world (such as the roar of an aircraft engine) is collected through a noise pickup microphone. Through the circuit or algorithm, the reverse noise signal is added to the music signal, which is the sound in the earphone heard by the human ear, and the external noise is directly cancelled out, so as to achieve the noise reduction effect.
After understanding the noise reduction principle of Bluetooth headsets, you should know what noise reduction function you need. The Bluetooth headset factory needs to remind: the disadvantage of active noise reduction is that it is basically ineffective against occasional and irregular noise. . The second is that it is generally only effective for mid- and low-frequency noise. The third is how much damage to the sound quality. Bluetooth headset noise reduction is divided into call noise reduction and environmental noise reduction. The former is to let others hear what you say clearly when you are on the phone, and the latter is to reduce external noise interference when listening to music. The least impact on sound quality is passive noise reduction. The best noise reduction effect is active noise reduction.
Passive Speaker:Bluetooth Speaker