Active Noise Cancellation (ANC) uses microphones and electronic circuitry to generate an "anti-noise" signal that cancels out background noise. In contrast, Passive Noise Isolation relies on the physical design and materials of the hearable to create a barrier that prevents ambient noise from entering the ear canal or around the ear. ANC provides superior noise reduction but requires additional power and components. In contrast, passive noise isolation is simpler and more cost-effective but may not be as effective in noisy environments.