What happens when a sound wave undergoes destructive interference?

When a sound wave undergoes destructive interference, the amplitudes of the interacting sound waves combine in such a way that they offset each other. If the waves are perfectly out of phase, their peaks coincide with the troughs of the other wave, resulting in complete cancellation of the sound. Even if the destructive interference is not perfect, it can significantly reduce the overall amplitude of the sound wave, leading to a reduction in perceived loudness. This phenomenon is crucial in various applications, such as noise-canceling headphones, which use destructive interference to minimize unwanted sounds.