1.1 这些规程包括根据试验方法进行吸声试验期间使用的试样安装件 C423 . 1.2 以国际单位制表示的数值应视为标准。括号中给出的值仅供参考。 ====意义和用途====== 4.1 覆盖平面的材料的吸声不仅取决于材料的物理特性，还取决于材料在表面上的安装方式。这些实践中规定的安装旨在模拟正常使用中存在的实验室条件。 4.2 一些指定的安装需要特殊的固定装置或与正常做法的微小偏差。这些固定装置或偏差仅在实验室测试期间使用，不应指定用于实际安装。在有关安装件的规范中，它们用短语“仅用于实验室测试”表示 4.3 测试报告可按型号名称提及这些安装件，而不是提供所用安装件的详细说明。

1.1 These practices cover test specimen mountings to be used during sound absorption tests performed in accordance with Test Method C423 . 1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. ====== Significance And Use ====== 4.1 The sound absorption of a material that covers a flat surface depends not only on the physical properties of the material but also on the way in which the material is mounted over the surface. The mountings specified in these practices are intended to simulate in the laboratory conditions that exist in normal use. 4.2 Some of the specified mountings require special fixtures or minor deviations from normal practice. These fixtures or deviations are to be used only during laboratory tests and should not be specified for practical installations. They are noted in the specifications for the mountings in question by the phrase “for laboratory testing only.” 4.3 Test reports may refer to these mountings by type designation instead of providing a detailed description of the mounting used.