Evaluation of a method for the measurement of subwoofers in usual rooms.
Evaluation of a method for the measurement of subwoofers in usual rooms.
复制标题
DOI：
10.1121/1.3270392
复制
发表时间：
2010-01
期刊：
影响因子：
--
通讯作者：
M. Melon;C. Langrenne;P. Herzog;Alexandre Garcia
中科院分区：
文献类型：
--
作者：
M. Melon;C. Langrenne;P. Herzog;Alexandre Garcia
本文评估了场分离法(FSM)在吸声性能较差的小型测试室中进行低音扬声器测量的潜力。有限状态机需要知道被测源周围封闭表面上的声压场和声速场。用p-p探头在半球网上测量了不同条件下的压力和速度：在一个混响时间可变(S 6.40.6)和四个测量半球半径的房间里。对测量数据进行球谐展开，分离出向外传播和向内传播。然后，从测量场中减去周围房间墙壁反射的压力场，以估计在自由场条件下本应辐射的压力场。从薄膜运动的扩展Thiele和Small模型出发，结合用于计算辐射压力的边界元模型，并考虑实际的低音扬声器几何形状，使用解析公式计算低音扬声器的理论频率响应。测量结果与仿真结果吻合较好。讨论了测量距离、测量点数和室内混响时间对分离过程的影响。
This paper evaluates the potential of the field separation method (FSM) for performing subwoofer measurements in a small test room with poor absorbing properties, as is commonly available. The FSM requires the knowledge of both acoustic pressure and velocity fields on a closed surface surrounding the tested source. Pressures and velocities, measured using a p-p probe on a half-sphere mesh, are collected under various conditions: in a room with variable reverberation time (6.4-0.6 s) and with four measurement half-sphere radii. The measured data are expanded on spherical harmonics, separating outward and inward propagation. The pressure field reflected by walls of the surrounding room is then subtracted from the measured field to estimate the pressure field that would have been radiated under free-field conditions. Theoretical frequency response of the subwoofer is computed using an analytical formulation derived from an extended Thiele and Small model of the membrane motion, coupled to a boundary element model for computing the radiated pressure while taking into account the actual subwoofer geometry. Measurement and simulation results show a good agreement. The effects of the measurement distance, the measurement point number, and the room reverberation time on the separation process are then discussed.