Heuchel Franz M, Fernandez-Grande Efren, Agerkvist Finn T, Shabalina Elena
Acoustic Technology Group, Department of Electrical Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
d&b audiotechnik GmbH, 71522 Backnang, Germany.
J Acoust Soc Am. 2018 Mar;143(3):1346. doi: 10.1121/1.5024903.
This work investigates how the sound field created by a sound reinforcement system can be controlled at low frequencies. An indoor control method is proposed which actively absorbs the sound incident on a reflecting boundary using an array of secondary sources. The sound field is separated into incident and reflected components by a microphone array close to the secondary sources, enabling the minimization of reflected components by means of optimal signals for the secondary sources. The method is purely feed-forward and assumes constant room conditions. Three different sound field separation techniques for the modeling of the reflections are investigated based on plane wave decomposition, equivalent sources, and the Spatial Fourier transform. Simulations and an experimental validation are presented, showing that the control method performs similarly well at enhancing low frequency responses with the three sound separation techniques. Resonances in the entire room are reduced, although the microphone array and secondary sources are confined to a small region close to the reflecting wall. Unlike previous control methods based on the creation of a plane wave sound field, the investigated method works in arbitrary room geometries and primary source positions.
这项工作研究了如何在低频下控制扩声系统产生的声场。提出了一种室内控制方法，该方法使用次级声源阵列主动吸收入射到反射边界上的声音。通过靠近次级声源的麦克风阵列将声场分离为入射分量和反射分量，从而能够通过为次级声源提供最优信号来最小化反射分量。该方法是纯前馈的，并假设房间条件恒定。基于平面波分解、等效源和空间傅里叶变换，研究了三种不同的用于反射建模的声场分离技术。给出了仿真和实验验证，结果表明，对于这三种声音分离技术，该控制方法在增强低频响应方面表现同样出色。尽管麦克风阵列和次级声源局限于靠近反射墙的一个小区域，但整个房间内的共振得到了降低。与以往基于创建平面波声场的控制方法不同，所研究的方法适用于任意的房间几何形状和初级声源位置。
