anekoïsche

Anekoïsche is an adjective used in acoustics and related fields to describe conditions, spaces, or measurements that produce little to no acoustic reflection, i.e., echo-free. In Dutch usage, it is closely linked to the concept of anechoic, as in anekoïsche ruimte or anekoïsche kamer, and often contrasts with reverberant environments.

Etymology: The term derives from Greek an-, without, and echo; the form in Dutch uses the diaeresis in -oïsche or -oïsche, reflecting pronunciation. In practice, the Dutch adjective designates a state of near-ideal free-field acoustics.

Construction and properties: An anekoïsche space is built with extensive sound-absorbing materials on walls, ceiling and floor, frequently in pyramid or wedge shapes, to minimize reflections across the audible spectrum. The room is off-axis to reduce standing waves and is mechanically isolated to limit external noise. Some chambers also employ floating floors and vibration isolation. The resulting reverberation time is extremely short, often near zero seconds over most frequencies, yielding a near free-field sound field.

Applications: Used in acoustic research, loudspeaker and microphone testing, product development for consumer electronics, automotive acoustics, and psychoacoustic experiments. It enables measurements of direct sound without room interference and improves repeatability of results.

Limitations and experience: The environment is extremely quiet and can feel disorienting; some individuals perceive the absence of reflections as unnatural, and bodily sounds may become audible. The chamber is not a universal standard for all acoustic measurements, as some tests require controlled reverberation.

See also: anechoic chamber, reverberation chamber, acoustic measurement, sound absorption.