free field
A space where sound waves can propagate without being obstructed or reflected by other surfaces. It’s an environment where sound travels directly from the source and is not altered by reflections off walls, ceilings, or other objects. This allows for accurate measurements of a sound source because the sound energy only passes through the measuring point once. An anechoic chamber, with sound-absorbing materials on all surfaces, simulates a free field. (Kremer, 2025)