On the Modeling of Rectangular Geometries in Room Acoustic Simulations
On the Modeling of Rectangular Geometries in Room Acoustic Simulations
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室内声学仿真中矩形几何形状的建模
DOI：
10.1109/taslp.2015.2405476
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
T. V. Waterschoot
中科院分区：
文献类型：
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作者：
E. D. Sena;Niccolò Antonello;M. Moonen;T. V. Waterschoot
本文关注的是一种称为扫频回声的声学现象，它在房间脉冲响应中表现为独特的、连续的音调增加。本文表明，在所有完美的矩形房间中都存在扫频回声（尽管程度差异很大）。理论分析基于波动方程的刚性壁图像解。研究发现，扫频回波是由接近三个轴向的方向到达的高阶反射的有序时间排列引起的。虽然以前曾在几何形状与矩形模型（例如壁球场）非常相似的真实房间中观察到扫频回声，但在常见的房间中却看不到它们。图像法 (IM) 和时域有限差分 (FDTD) 等房间声学模拟器可以正确预测这种现象的存在，这意味着当目标是对常见房间进行建模时，应谨慎使用矩形几何形状。房间几何形状中小的非方形不对称性被证明可以显着减少这种现象。图像源位置的随机化可以消除扫频回波，而无需显式地对不对称几何结构进行建模。最后，三种语音和音频处理算法的性能被证明对强扫回声很敏感，因此强调需要避免它们的发生。
This paper is concerned with an acoustical phenomenon called sweeping echo, which manifests itself in a room impulse response as a distinctive, continuous pitch increase. In this paper, it is shown that sweeping echoes are present (although to greatly varying degrees) in all perfectly rectangular rooms. The theoretical analysis is based on the rigid-wall image solution of the wave equation. Sweeping echoes are found to be caused by the orderly time-alignment of high-order reflections arriving from directions close to the three axial directions. While sweeping echoes have been previously observed in real rooms with a geometry very similar to the rectangular model (e.g., a squash court), they are not perceived in commonly encountered rooms. Room acoustic simulators such as the image method (IM) and finite difference time-domain (FDTD) correctly predict the presence of this phenomenon, which means that rectangular geometries should be used with caution when the objective is to model commonly encountered rooms. Small out-of-square asymmetries in the room geometry are shown to reduce the phenomenon significantly. Randomization of the image sources' position is shown to remove sweeping echoes without the need to model an asymmetrical geometry explicitly. Finally, the performance of three speech and audio processing algorithms is shown to be sensitive to strong sweeping echoes, thus highlighting the need to avoid their occurrence.