Noise-canceling headsets are a kind of headsets that reduce noise through a certain method. The current noise cancelling headsets with mic are divided into two noise cancelling modes: passive noise cancelling and active noise cancelling.
Passive noise cancelling is an outdated method of noise cancelling. The reason why passive noise cancelling is used is because it does not rely on the support of technology, thus reducing costs.
Wrapped to form a closed space
Passive noise-cancelling headsets mainly form a closed space by wrapping the ears, and use sound-insulating materials such as silicone earplugs to block external noise. Without the aid of technology, passive noise-canceling headsets can only block high-frequency noise, but can't do anything about low-frequency noise.
Generally, passive noise cancelling headphones are headsets, and they are huge in size. For those who want to reduce noise in summer, passive noise cancelling is a very unwise way.
The prerequisite principle of active noise cancelling is the interference principle of waves, which neutralizes the noise through positive and negative sound waves, so as to achieve the noise cancelling effect.
When two wave crests or wave troughs meet, the displacements of the two waves will be superimposed on each other, and the vibration amplitude will also be added.
When the peak and valley meet, the vibration amplitude of the superposition state will be canceled
On an active noise cancelling headset or an active noise cancelling earphone, there must be a hole or part of it facing the opposite direction of the ear. Some people will wonder what it is for. This part is used to collect external sounds. After the external noise is collected, the processor in the earphone will create an anti-noise source in the opposite direction to the noise.
Finally, the anti-noise source and the sound played in the earphone are transmitted together, so that we can't hear the outside sound.
It is called active noise cancelling because it can be artificially determined whether to calculate the anti-noise source.