L.On the coefficient of sound-absorption measured by the reverberation method
L.On the coefficient of sound-absorption measured by the reverberation method
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L.关于混响法测量的吸声系数
DOI：
10.1080/14786440308565092
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发表时间：
1928
期刊：
影响因子：
--
通讯作者：
E. T. P. D.Sc.
中科院分区：
文献类型：
--
作者：
E. T. P. D.Sc.
在本文中，我们试图把一种物质在某一特定波长上的吸收系数，用入射角的函数来表示，与萨比纳混响法测定的同一波长上的吸收系数联系起来。萨宾齿测量的系数称为“吸收混响系数”，用at表示。入射于O角的波的吸收系数用a (O)表示。由Sabine、Jiiger等人提出的混响理论是对理论声学中经典方法的一种背离，它涉及到在发生混响的封闭空间中有关声能分布和行为的某些假设。近年来，EA Eckhardt*和E. Buckingham J'。这里不讨论所涉及的假设的有效性问题，但我们的注意力将限于考察在混响理论中引入系数a(0)的结果，目的是找出~（~）和at之间的关系。在发生混响的房间里，声能撞击墙壁的频率可计算如下：设dS为声能密度p为均匀的房间墙壁的面积元，设dV为距离dS为r处，方向与法向n与dS成夹角0处的体积元（图1）。在任何时刻，dV中包含的能量pdV，那部分最终会击中，在立体角的方向上运动的dS
In the present paper an attempt is made to correlate the cosfficient of absorption of a substance, measured at some particular wave-lelJgth and expressed as a function of the angle oi incidence, with the coefficient of absorption determined by Sabine's reverberation method for the same wave-length.The coefficient measured by Sabine's toothed will be called the" reverberation coefficient of absorption" and denoted by at. The coefficient of absorption for waves incident at an anglo O will be denoted by a (O). The theory of reverberation as developed by Sabine, Jiiger, and others is a departure from classical methods in theorei, ical acoustics, and involves certain assmnptions regarding the distribution and behaviour of sound-energy in an enclosed space in which reverberation is occurring. Accounts of the theory and of the assumptions made have been given in recent years by EA Eckhardt* and E. Buckingham J'. The question of the validity of the assu, nptions involved will not be discussed here, but attention will be confined to examining the result of introducing the coefficient a (0) into the theory of reverberation with the object of finding a relation between~(~) and at. Tile rate at which sound-energy strikes the walls of a room in which reverberation is occurring is found as follows:~. Let dS be an element of area of the wall of a room in which the acoustical energy-density p is uniform, and let dV be an element of volume at a distance r from dS in a direction making an angle 0 with the normal n to dS (fig. 1). Of the energy pdV contained within dV at any instant, that portion will ultimately strike dS which is moving within directions included within the solid angle