ANC Microphone Placement and How It Works

By Priya Nair · October 10, 2026

Active Noise Cancellation Fundamentals

Active noise cancellation (ANC) works by recording ambient noise with microphones, inverting the signal, and playing it back through the headphone driver to destructively interfere with the incoming noise. The placement and type of these microphones fundamentally determines what frequencies the ANC can cancel.

Feedforward ANC (External Microphones)

Feedforward systems mount microphones on the outside of the ear cup. They capture noise before it reaches your ear, giving the DSP time to generate the anti-noise signal. This approach works best at mid frequencies (300-1000 Hz).

Feedforward Characteristics

Effective against mid-frequency noise: HVAC hum, traffic rumble, airplane cabin noise
Less effective against sudden transient sounds
External mics can pick up wind noise, causing ANC artifacts
Does not correct for how noise actually sounds at your eardrum

Feedback ANC (Internal Microphones)

Feedback systems place microphones inside the ear cup, near the driver. They listen to what your ear actually hears — the combination of external noise leaking through the passive seal plus the anti-noise signal. The DSP then adjusts the anti-noise in real time.

Feedback Characteristics

More accurate cancellation because it corrects at the ear, not at the shell
Better at lower frequencies (50-300 Hz) where passive isolation is weak
Can introduce instability if the gain is too high
Limited bandwidth because the internal mic hears the driver output mixed with noise

Hybrid ANC: Best of Both

Premium ANC headphones (Sony WH-1000XM series, Bose QuietComfort, Apple AirPods Max) use both feedforward and feedback microphones simultaneously. The feedforward mics handle mid-frequency noise with lead time, while the feedback mics refine the cancellation at the ear for low-frequency accuracy.

What the Microphones Actually Hear

Modern ANC systems use 4-8 microphones per ear cup, with beamforming algorithms that separate noise from audio content. Adaptive algorithms continuously adjust cancellation depth based on the noise environment.