{"id":285879,"date":"2025-06-17T07:34:51","date_gmt":"2025-06-17T07:34:51","guid":{"rendered":"https:\/\/design.crysound.com\/camara-anecoica-explicada-tipos-normas-de-diseno-y-como-realizar-pruebas-sin-una-2\/"},"modified":"2026-08-14T07:24:01","modified_gmt":"2026-08-14T07:24:01","slug":"camara-anecoica-explicada-tipos-normas-de-diseno-y-como-realizar-pruebas-sin-una-2","status":"publish","type":"post","link":"https:\/\/design.crysound.com\/es\/blog\/camara-anecoica-explicada-tipos-normas-de-diseno-y-como-realizar-pruebas-sin-una-2\/","title":{"rendered":"C\u00e1mara anecoica explicada: tipos, normas de dise\u00f1o y c\u00f3mo realizar pruebas sin una"},"content":{"rendered":"

What Is an Anechoic Chamber?<\/h2>\n

An anechoic chamber is a room designed to completely absorb sound reflections. The walls, ceiling, and (in a full anechoic chamber) the floor are lined with wedge-shaped foam or fibreglass absorbers that prevent sound waves from bouncing back into the room.<\/p>\n

The result is a controlled acoustic environment that simulates free-field conditions<\/strong> - as if the sound source were suspended in open air with no surfaces nearby.<\/p>\n

This matters because most acoustic measurements - sound power, directivity, frequency response - require a known, reflection-free environment to produce repeatable, standards-compliant results. Without it, room reflections contaminate the measurement, making results dependent on the specific room rather than the product being tested.<\/p>\n

\"Interior<\/figure>\n

Full Anechoic vs Semi-Anechoic (Hemi-Anechoic) Chambers<\/h2>\n
\"Comparison<\/figure>\n
<\/div>\n
\n\n\n\n\n\n\n\n\n\n\n\n
Feature<\/th>\nFull Anechoic<\/th>\nSemi-Anechoic (Hemi-Anechoic)<\/th>\n<\/tr>\n<\/thead>\n
Absorbing surfaces<\/strong><\/td>\nAll 6 surfaces (walls, ceiling, floor)<\/td>\n5 surfaces (walls + ceiling); floor is reflective<\/td>\n<\/tr>\n
Floor<\/strong><\/td>\nWire mesh or perforated metal grid suspended above absorbers<\/td>\nSolid, load-bearing concrete or steel<\/td>\n<\/tr>\n
Acoustic condition<\/strong><\/td>\nFree-field (no reflections from any direction)<\/td>\nFree-field over a reflecting plane<\/td>\n<\/tr>\n
Load capacity<\/strong><\/td>\nLimited - cannot support heavy equipment directly<\/td>\nCan support vehicles, machinery, industrial equipment<\/td>\n<\/tr>\n
Primary standards<\/strong><\/td>\nISO 3745 (precision sound power)<\/td>\nISO 3744 (engineering sound power), ISO 3745<\/td>\n<\/tr>\n
Typical use<\/strong><\/td>\nMicrophone calibration, loudspeaker characterisation, hearing research<\/td>\nAutomotive NVH, product noise testing, industrial machinery<\/td>\n<\/tr>\n
Cost<\/strong><\/td>\nHigher (floor treatment adds significant cost and complexity)<\/td>\nLower (no floor treatment needed)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/figure>\n

In practice, about 80% of industrial acoustic testing<\/strong> uses semi-anechoic chambers because most test objects - cars, appliances, compressors, power tools - are too heavy for a suspended wire-mesh floor.<\/p>\n

What Standards Require an Anechoic Chamber?<\/h2>\n

ISO 3745 - Precision Sound Power Measurement<\/h3>\n

The gold standard for sound power determination. Requires either a full anechoic or hemi-anechoic chamber qualified to meet strict free-field deviation limits across the frequency range of interest. The chamber must demonstrate that the inverse-square law holds to within \u00b11 dB at the measurement positions.<\/p>\n

Typical cut-off frequency:<\/strong> 80-200 Hz, depending on chamber size and wedge depth. Below this frequency, the chamber no longer behaves as a free field.<\/p>\n

ISO 3744 - Engineering Sound Power Measurement<\/h3>\n

Less stringent than ISO 3745 but still requires a hemi-anechoic environment. Allows for environmental corrections when the room is not perfectly anechoic, making it practical for production-floor test cells that approximate (but do not perfectly achieve) free-field conditions.<\/p>\n

ISO 26101 - Qualification of Free-Field Environments<\/h3>\n

Defines how to verify whether a room actually meets free-field requirements. This is the standard used to \"qualify\" an anechoic or hemi-anechoic chamber - confirming that its acoustic performance matches what is claimed.<\/p>\n

Other Standards<\/h3>\n