anecoiche

Anecoiche is a term sometimes encountered in discussions of acoustic and electromagnetic testing that refers to environments or measurements conducted in the absence of echoes or reflections. In English, the more common form is anehoic; anecoiche is typically considered a variant or misspelling. The concept, however, remains the same: a space designed to absorb incoming waves so that little or no reflected energy remains.

In acoustics, an anechoic chamber uses extensive sound-absorbing materials on walls, ceiling, and floor, often in conical or wedge-shaped panels, to minimize reflections across a wide frequency range. The room aims to approximate a free-field environment, enabling precise loudspeaker, microphone, and human-perception experiments. The floor is sometimes suspended or consists of perforated panels decoupled from the structure to reduce floor bounce. Voice and sound measurements taken inside are dominated by direct sound from the source rather than reverberant energy.

In electromagnetics, an anechoic chamber lines its interior with RF-absorbing materials to suppress reflections of microwaves and other radio frequencies. This creates a quiet electrical environment suitable for antenna testing, radar cross-section measurements, and electromagnetic compatibility testing. The chamber is designed to create a stable, near-free-space condition over designated frequency bands; design details vary by frequency.

Limitations include incomplete absorption at some frequencies, boundary resonances, and the cost of construction and maintenance. While effective, such spaces do not replicate all outdoor or in-room acoustic or electromagnetic conditions.