Coleman Philip, Jackson Philip J B, Olik Marek, Pedersen Jan Abildgaard
Centre for Vision, Speech and Signal Processing, University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom.
Bang & Olufsen A/S, Peter Bangs Vej 15, DK7600, Struer, Denmark.
J Acoust Soc Am. 2014 Oct;136(4):1725-35. doi: 10.1121/1.4893909.
Reproduction of multiple sound zones, in which personal audio programs may be consumed without the need for headphones, is an active topic in acoustical signal processing. Many approaches to sound zone reproduction do not consider control of the bright zone phase, which may lead to self-cancellation problems if the loudspeakers surround the zones. Conversely, control of the phase in a least-squares sense comes at a cost of decreased level difference between the zones and frequency range of cancellation. Single-zone approaches have considered plane wave reproduction by focusing the sound energy in to a point in the wavenumber domain. In this article, a planar bright zone is reproduced via planarity control, which constrains the bright zone energy to impinge from a narrow range of angles via projection in to a spatial domain. Simulation results using a circular array surrounding two zones show the method to produce superior contrast to the least-squares approach, and superior planarity to the contrast maximization approach. Practical performance measurements obtained in an acoustically treated room verify the conclusions drawn under free-field conditions.
多个声区的再现是声学信号处理中的一个热门话题，在这些声区中，个人音频节目无需耳机即可收听。许多声区再现方法没有考虑明亮区相位的控制，如果扬声器环绕这些声区，这可能会导致自抵消问题。相反，在最小二乘意义上控制相位会导致声区之间的电平差和抵消频率范围减小。单区方法通过将声能聚焦到波数域中的一个点来考虑平面波再现。在本文中，通过平面度控制再现平面明亮区，该控制通过投影到空间域将明亮区能量限制在狭窄的角度范围内入射。使用围绕两个区域的圆形阵列的仿真结果表明，该方法比最小二乘方法具有更好的对比度，比对比度最大化方法具有更好的平面度。在经过声学处理的房间中获得的实际性能测量结果验证了在自由场条件下得出的结论。
