Active vs. Passive

Active noise cancellation (ANC) uses microphones, DSP chips, and speakers to generate anti-phase waves. It requires battery power and works best on steady, low-frequency noise. Premium ANC headphones use multiple microphones, some facing outward to sample the environment and others facing inward toward the ear to fine-tune the cancellation.

Passive noise isolation relies purely on physical barriers. Dense foam, tight-sealing ear tips, and heavy ear cups block sound by absorbing and reflecting it. Passive isolation can reduce a broad range of frequencies, but the amount depends on fit, seal, material, and the sound's wavelength.

Most modern headphones combine both approaches.