Wang P., Johns M., Callahan D.

Directional microphones are very useful in locating the sources of objectionable sound and perform measurements in noisy environments by excluding extraneous sources. Not long ago, most applications relied on parabolic or elliptical mirror microphones. Nowadays, steer-able phased microphone array is more flexible and less bulky. Using phased array for acoustics in source identification was prohibited by frequency limitation and high cost of large number of sensors and instrumentations. But now, multi-channel data acquisition instrumentation and microphone sensors have become affordable. A new type of array design based on the semi-random configuration has been shown previously by the authors to have advantage over the traditional fixed array. In this paper, we introduce the array design with quasi-random configuration to defeat the bandwidth limitation and maximize the functionality using least amount of sensors. The array is designed so that there is essentially no repeating vector in the co-array space, thus the optimal array design can be achieve with best performance in each test. The performance of the old and new array concepts will be illustrated with examples, and the data compared with traditional array. The sidelobe levels and beam pattern are also compared. The concept can be implemented easily and does not require extra labor, all configurations can be initiated and automated by the computer software.