扬声器阵列空间声场控制研究

发布时间：2019-03-02 10:51

【摘要】：空间声场控制是指采用扬声器阵列进行特定声场重放或对特定区域内的空间声场分布进行调控。空间声场控制在音频系统中有广泛应用,包括音乐厅、影剧院、家庭影院系统、飞机或车辆内的音频系统等。本文在回顾现有空间声场控制理论的基础上,研究采用线性扬声器阵列在具有弯曲边界的区域中产生较高声能量而保持其他区域声能量较低的方法。首先,提出一种采用线性扬声器阵列产生沿任意弯曲轨迹传播的声场的方法,该方法通过调控扬声器阵列的空间相位分布产生一系列切线形成弯曲轨迹的包络。本文给出产生任意弯曲轨迹的一般化推导过程同时探索该方法的控制机理,指出该方法理论基础为稳相法,即弯曲轨迹上某点的声压主要来自于经过该点的切线上的声源的贡献,而其他声源在该点的声压则相互抵消。其次,根据上述切线法空间声场控制的理论,进行仿真和实验验证。仿真结果表明采用线性扬声器阵列产生的弯曲轨迹与理论预期相吻合,同时以半圆形轨迹为例讨论了需要的扬声器阵列长度与传播距离和弯曲轨迹尺寸的关系。另外,在消声室环境中采用64个扬声器单元组成的阵列实验实现了抛物线轨迹、四分之一圆形轨迹和半圆形轨迹的声波束,并通过仿真和实验证明该方法对障碍物散射具有较好的鲁棒性。最后,探索了所提切线法空间声场控制在声对比度控制系统中的应用。通过仿真研究了切线法在弧形弯曲区域产生较高声能量而在其他区域产生较低声能量的性能,并和声能量差最大法进行比较。仿真结果表明,切线法可以在声对比度和亮区的声均匀度之间取得权衡,且对扬声器响应失配和位置扰动具有较好的鲁棒性。时域仿真结果表明切线法具有更平的频响,因而可以产生更好的音质。
[Abstract]:Spatial acoustic field control refers to the use of loudspeaker array to replay the specific sound field or to regulate the distribution of spatial sound field in a specific area. Space sound field control is widely used in audio systems, including concert halls, cinemas, home theater systems, audio systems in aircraft or vehicles, and so on. On the basis of reviewing the existing control theory of spatial acoustic field, this paper studies the method of using linear loudspeaker array to generate higher acoustic energy in the region with curved boundary and to keep the acoustic energy low in other regions. Firstly, a linear loudspeaker array is proposed to generate sound fields that propagate along arbitrary curved tracks. By adjusting the spatial phase distribution of the loudspeaker array, a series of tangents are generated to form the envelope of the curved trajectory. In this paper, the general derivation process of arbitrary bending trajectory is given and the control mechanism of the method is explored simultaneously. It is pointed out that the theoretical basis of this method is the stable phase method. That is, the sound pressure of a point on the bend track is mainly due to the contribution of the sound source passing through the tangent line of the point, while the sound pressure of the other sound sources at the point is counteracted by each other. Secondly, according to the theory of spatial acoustic field control by tangent method, simulation and experiment are carried out. The simulation results show that the bending trajectory generated by the linear loudspeaker array is consistent with the theoretical expectation, and the relationship between the length of the required loudspeaker array and the propagation distance and the curved trajectory size is discussed by taking the semicircular trajectory as an example. In addition, the acoustic beam of parabola track, 1/4 circular track and semi-circular track is realized by array experiment of 64 loudspeaker elements in anechoic chamber environment. The simulation and experimental results show that the proposed method is robust to obstacle scattering. Finally, the application of spatial acoustic field control based on tangent method in acoustic contrast control system is explored. The performance of tangential method which produces higher acoustic energy in curved region and lower acoustic energy in other regions is studied by simulation and compared with the maximum method of acoustic energy difference. The simulation results show that the tangent method can balance the sound contrast with the sound uniformity in the bright area, and it is robust to the loudspeaker response mismatch and position disturbance. The time domain simulation results show that the tangent method has a more flat frequency response, so it can produce better sound quality.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN643

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