Simple Explanation

When two sound waves meet in such a way that they reduce or eliminate each other.

Concise Technical Definition

The phenomenon where two sound waves of the same frequency and opposite phase interfere destructively, reducing amplitude or fully nullifying the sound.

Layman-Friendly Analogy

Like two people pushing on a door from opposite sides with equal force—nothing moves.

Industry Usage Summary

Common in acoustics, live sound, and speaker design. Seen in phase alignment issues, room reflections, and noise-canceling technology (like ANC headphones).

Engineering Shortcut

Same frequency + 180° phase offset = cancellation (partial or total).

Full Technical Explanation

Cancellation occurs when two sound waves of equal frequency and amplitude are 180° out of phase. Their peaks align with the other’s troughs, causing destructive interference. In acoustics, this can result in notches in frequency response (e.g., comb filtering or SBIR). In active noise cancellation, a device generates an inverse wave to cancel ambient noise. Engineers must manage cancellation when designing speaker arrays, subwoofer placement, or dealing with reflections in rooms.