What are the active noise reduction of Bluetooth headset manufacturers?

Bluetooth headset manufacturers said earlier that there are three noise reduction methods currently used in Bluetooth headsets, and they also mentioned that active noise reduction will lead the trend of Bluetooth headsets, so what is the specific principle of active noise reduction? How many solutions or methods are there? Today, what are the active noise reduction of Bluetooth headset manufacturers?

Bluetooth headset manufacturer
At present, the main active noise reduction functions of Bluetooth headset manufacturers are roughly divided into four types, namely ANC, ENC, CVC, DSP and other noise reduction technologies
Noise reduction headphones, using ANC noise reduction and active noise control, are mainly aimed at high and low frequency noise in the external environment. They are different from the passive sound insulation of general headphones. The principle is:

1. First detect the low-frequency noise (100 ~ 1000Hz) in the environment that the ear can hear by the signal microphone installed in the earphone (currently it can reach 3000Hz)
2. The noise signal is transmitted to the control circuit, and the control circuit performs real-time calculations
3. Through the Hi-Fi horn, the sound wave with the opposite phase and the same amplitude is added to the external noise to cancel the noise

4. So the noise disappears and is inaudible

Active noise reduction is divided into feedforward active noise reduction and feedback active noise reduction according to the position of the pickup microphone.
In this way, this headset needs a period of algorithm processing time, first learning the noise, this learning needs time, and then the phase of the learned noise is reversed, and there is an adaptive adjustment period.
Active noise-canceling headphones are expensive, but they are generally effective and comfortable to wear. But it needs independent battery power supply, most passive noise reduction headphones can be used without power consumption (nor active noise reduction)

ENC noise reduction
ENC (Environmental Noise Cancellation, environmental noise reduction technology), 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 accurately calculates the direction of the caller's speech, which protects the target voice in the main direction while removing various interference noises in the environment.

DSP noise reduction
DSP is an abbreviation for English (digital signal processing). 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.

CVC noise reduction
CVC (Clear Voice Capture) is a noise reduction technology for call software. Mainly for the echo generated during the conversation. Through the full-duplex microphone noise cancellation software, it provides the echo and environmental noise cancellation function of the call. It is the most advanced noise reduction technology in the current Bluetooth call headset.
The main reason why Bluetooth headset manufacturers predict that Bluetooth headsets will lead the trend with active noise reduction in the future is that the upstream R&D companies of Bluetooth headset manufacturers, especially chip companies, plan companies to provide active noise reduction solutions, and even mic companies are now Research in the direction of active noise reduction. Although there is currently no relevant data support, Bluetooth headset manufacturers can judge from the actions of upstream companies that active noise reduction will be the mainstream of the Bluetooth headset industry.
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