## College Physics (4th Edition)

This technology is based on the principle of destructive interference. The headphones take the original electrical signal and then produce a signal that is $180^{\circ}$ out of phase with the original signal.
This technology is based on the principle of destructive interference. The headphones produce a sound wave that interferes destructively with the original sound wave, thus attenuating the sound. The headphones takes the original electrical signal and then produces a signal that is $180^{\circ}$ out of phase with the original signal. When two signals are $180^{\circ}$ out of phase, they should interfere destructively.