本文件描述了测量环境性能的散度损失方法，该环境设计用于在反射面上提供自由声场或自由声场。声环境是一个自由声场，前提是它的边界表面能吸收入射到其上的所有声能。这通常是通过使用专门的测试环境，如消声室或半消声室来实现的。实际上，它们为设施内的受限空间内的声学测量提供受控自由声场。

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.