Müra{0}}summutavate kõrvaklappide põhimõte

Müra{0}}summutavate kõrvaklappide põhimõte

       We know that sound waves are essentially mechanical vibrations of the medium. Junior high school physics textbooks tell us that sound waves are generally longitudinal waves, but for the convenience of understanding, we use transverse waves for discussion here. The shape of a transverse wave, which we can roughly understand as a sine wave, has peaks and troughs. If two beams propagate to the same place, how does the sound medium in this place move? Its motion satisfies the principle of superposition of waves, and the motion of the medium in a certain place is equal to the superposition of the vibration of several beams in that place. For example, when a wave crest encounters a wave crest or a wave trough encounters a wave trough, the amplitude of movement of the place is the sum of the amplitudes of the two beams. reduce. This behavior of several beams hitting the same place will produce a superposition effect, which is called wave interference.

     The principle of noise{{0}}cancelling headphones is to use the interference of waves. If two identical sound waves hit your ears, if the crest meets the crest and the trough meets the trough, you will hear four times the volume, because the energy of the sound is proportional to the square of the amplitude of the sound wave, and the amplitude changes. Doubled, the energy is quadrupled. If the peak and the trough meet, the positive and negative offsets, the amplitude of the sound is 0, you will feel very quiet, because the sound is completely canceled. Noise-cancelling headphones not only have speakers, but also a microphone, which is designed to capture ambient noise.