There are three common technologies for ANC active noise reduction: feedforward, feedback, and composite. The difference between the three is the noise reception method. The principle is to receive external noise through a noise reduction microphone, and then process the noise signal through a DSP (Digital Signal Processor) to convert the inverse sound wave opposite to the noise sound wave to counteract the noise. Yes, active noise reduction mainly targets regular and predictable noises such as engine mechanical and environmental noise, but cannot eliminate irregular or sudden sounds such as vehicle horns.
The feedforward microphone is on the outside of the headset, the feedback type is on the inside of the headset, and the hybrid type has one inside and one outside. Each of the three technologies has its own advantages. The feed-forward technology is more accurate in eliminating external sounds because the microphone is on the outside, and can effectively reduce the external noise of 1~2Khz. The feedback technology can receive the sounds heard by the user and make real-time adjustments. The hybrid model combines the advantages of both, but is also the most expensive, like Airpods Pro.
Both earmuffs and true wireless headphones use feedforward and composite noise reduction technologies. The feedback type cannot be used alone. It can be regarded as a calculation unit to make up for the shortcomings of the feedforward type in real-time correction.
In addition, it should be mentioned that when active noise reduction is turned on, you can still hear the sound of people talking. Ordinary voices will not be filtered by the noise reduction system, except for sounds with lower frequency and irregular speech, so the noise of people around you cannot be eliminated. sound.
