Simple Explanation

The area far enough from a sound source where sound spreads out evenly and gets quieter with distance.

Concise Technical Definition

The region in a sound field where the sound pressure level (SPL) decreases by 6 dB for every doubling of distance, following the inverse square law.

Layman-Friendly Analogy

Like walking away from a flashlight—the farther you go, the dimmer it gets. Sound behaves the same way in the far field.

Industry Usage Summary

Used in acoustics, loudspeaker measurements, and environmental noise studies to describe where sound behaves predictably with distance. Important in defining mic placement and room tuning.

Engineering Shortcut

Region where SPL ∝ 1/d²; follows inverse square law.

Full Technical Explanation

The far field, or far sound field, is the area beyond the immediate vicinity of a sound source where the acoustic wavefronts are essentially spherical and the sound pressure level decreases predictably—by 6 dB with each doubling of distance (as per the inverse square law). This contrasts with the near field, where sound behavior is more complex and influenced by wave interference and proximity effects. In loudspeaker design and measurement, the far field is where frequency response becomes stable and consistent. The transition to far field depends on source size and wavelength.