Active Noise Cancellation (ANC) Explained
Active Noise Cancellation (ANC) is a technology that reduces unwanted background noise by generating sound waves that cancel out ambient noise. It works by creating "anti-noise" that counteracts incoming sound waves, effectively reducing what you hear. While ANC significantly reduces external noise, it rarely eliminates it completely.
There are three different implementations of ANC: Feedback, Feedforward, and Hybrid. Each comes with its own advantages and disadvantages.
Feedback ANC
Feedback ANC uses a microphone placed inside the ear cup to pick up the same sounds the listener hears. This allows the ANC to adapt to sudden changes and make effective signal corrections. Feedback ANC works well across a wide range of frequencies and even if the headset is worn unusually.
However, feedback ANC struggles with high-frequency sounds (particularly in the 1000-2000 Hz range). An improper design can lead to noise feedback. Also, the filter microphone being inside the ear cup can result in your music being filtered out.
Feedforward ANC
Feedforward ANC uses an external microphone to process noise before it reaches the listener. This allows feedforward ANC to handle high-frequency noises better.
However, since it doesn't hear the anti-noise it produces, feedforward ANC lacks self-correction. It also works within a narrower range of frequencies and is more sensitive to external noises like wind due to the external placement of the microphone.
Hybrid ANC
Hybrid ANC combines feedback and feedforward ANC by using both internal and external microphones. It provides the benefits of both methods while minimizing their disadvantages. Hybrid ANC suppresses noise over a broader range, adapts to sudden changes in noise, and isn't sensitive to the placement of the headset.
However, the use of two microphones increases manufacturing costs and complexity. The technology requires more expertise to implement properly. Original AirPods Pro use hybrid ANC, contributing to their higher price. Many current AirPods replicas now also implement hybrid ANC using advanced chipsets. For example, the v5.3 TB (featuring the Airoha 1571AM chipset) replicates the hybrid ANC effect for a full and authentic noise-canceling experience.
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Hybrid ANC, while more expensive, combines the benefits of both feedback and feedforward ANC, providing a more comprehensive noise-canceling experience.