ASA S12.79-2021/ISO 26101-2021 American National Standard for Acoustics - Test methods for the qualification of freefield environments

standard by American National Standards of the Acoustical Society of America, 10/25/2021

Full Description

This document describes the divergence loss method of measurement of performance of an environment designed to provide a free sound field or free sound field over a reflecting plane. An acoustical environment is a free sound field if it has bounding surfaces that absorb all sound energies incident upon them. This is normally achieved using specialized test environments, such as anechoic or hemi-anechoic chambers. In practice, these provide a controlled free sound field for acoustical measurements in a confined space within the facility.