On Mainlobe Orientation of the First- and Second-Order Differential Microphone Arrays
Quansheng Tu, Huawei Chen · IEEE/ACM Transactions on Audio Speech and Language Processing · 2019
Due to the increased sensitivity to microphone mismatches, lower-order differential microphone arrays (DMAs) are usually employed in practice, especially the first and second-order DMAs. It is known that the mainlobe orientation of the typical first- and second-order DMAs is both along the fixed endfire direction. This may be no longer true, however, in the presence of microphone mismatchs. This paper studies the fundamental problem of how microphone mismatches affect mainlobe orientation of the first- and second-order DMAs. Some insights into the effects of microphone mismatches on the mainlobe orientation of the two types of DMAs are revealed. In addition, the property on mainlobe orientation of the second-order DMA under ideal condition, which is yet to be known, is also studied. Moreover, tolerance analysis of microphone mismatches to ensure correct mainlobe orientation of the first- and second-order DMAs are performed in order to offer a useful guidance for practical design. Numerical examples are shown to verify the theoretical findings.