In your own words, describe how noise cancelling headphones work. Use vocabulary from this video and this unit.
Noise cancelling headphones use technology to reduce outside noise and improve audio quality. They work by using microphones to pick up external sounds and producing an opposite sound wave to cancel it out. This is called destructive interference, where two sound waves of opposite amplitude and frequency cancel each other out. This process is known as active noise cancellation and helps to reduce the overall amount of external sound that reaches the listener's ears. The two types of noise cancelling headphones are in-ear and over-ear, both of which utilize this technology to provide a more immersive audio experience for the user.
Noise cancelling headphones work by using a combination of hardware and software to reduce unwanted sounds, allowing you to enjoy your audio experience without interference. These headphones employ a technology called active noise cancellation (ANC) to achieve this.
The process starts with the headphones' microphones. There are usually two microphones: one on the exterior of the headphones and another on the inside. The external microphone captures the ambient sound, including external noises like traffic or chatter. The internal microphone picks up the sound that is being played through the headphones.
Once the microphones capture the sound, the headphones' circuitry processes this information. The circuitry analyzes the soundwaves and identifies the unwanted external noise by distinguishing it from the audio you want to hear. It then generates a corresponding soundwave that is precisely out of phase with the unwanted noise.
To generate this anti-noise, the headphones use a small built-in speaker called a driver. This driver is positioned close to the listener's ear. When the anti-noise signal is played through the driver, it cancels out the unwanted noise in real-time. This cancellation occurs because the anti-noise soundwave's peaks align with the unwanted noise's troughs, effectively neutralizing the sound. This process is known as destructive interference.
The ANC technology in noise cancelling headphones requires an additional power source, usually a rechargeable battery or AAA batteries. The power source supplies energy to the circuitry and the driver to perform the cancellation process effectively.
By combining these hardware components and software algorithms, noise cancelling headphones create an immersive audio experience by actively eliminating ambient noise and allowing you to focus on the intended audio content.