Room Acoustics Modelling

在过去的几十年中，循环试验令人信服地表明，在没有充分考虑声音的衍射和散射的情况下，常见的几何建模方案不能可靠地预测封闭空间中的声场。作为一种建模工具，其中的物理属性，即，德尔夫特工业大学充分考虑了声音的波动特性，提出了所谓的WRW室内声学建模概念，该概念源自石油和天然气地震勘探中常用的建模方案。WRW模型的计算方案是基于声波波动方程。矩阵R描述房间边界的局部反射特性，矩阵W指定到每个边界点和来自每个边界点的声音传播。这个子项目的目标是将WRW模型从一个有吸引力的概念发展成一个可操作的、有效的模拟工具。为了实现这一目标，必须确定房间边界反射特性的适当描述，并将其插入到矩阵R中。在通过麦克风阵列测量数据的逆外推确定这些属性之后，必须编译用于共同边界构造的这种反射率属性的库。还必须研究如何以计算上最有效的方式计算所有边界点之间的声音传播，如矩阵W所描述的。该子项目的最终产品应是一个模拟软件包，能够准确和预测模拟复杂外壳中的三维声波场，作为研究的参考工具。

Round-robin tests during the last decades have convincingly shown that the common geometric modelling schemes where diffraction and scattering of sound are not adequately taken into account do not reliably predict sound fields in enclosed spaces. As a modelling tool in which the physical properties, i.e., the wave character, of sound is fully taken into account, TU Delft proposed the so-called WRW room acoustics modelling concept, derived from a modelling scheme commonly used in seismic exploration of oil and gas. The calculation schemes of the WRW model are based on the acoustic wave equation. Matrices R describe the local reflective properties of the room boundaries, matrices W specify the sound propagation to and from each boundary point. Goal of this subproject Is to develop the WRW model from an attractive concept to an operational and efficient simulation tool. To realize this goal, an appropriate description of the reflective properties ofthe room boundaries should be determined, to be Inserted in the matrices R. A library of such reflectivity properties for common boundary constructions has to be compiled, after determination of these properties by inverse extrapolation of microphone array measurement data. It also has to be investigated how the sound propagation between all boundary points, as described by the matrices W, can be calculated In a computationally most effective way. The end product of the subproject should be a simulation software package enabling the accurate and predictive simulation of 3D acoustic wave fields in complex enclosures, as a reference tool for research.