Study and Design of Second-Order Differential Arrays - Study and Design of Differential Microphone Arrays - page 91

2Δ

FIG. 4.30 A two-dimensional differential array.

4.5 Steering

As explained in the previous chapter, it is not possible to steer with a uniform
linear DMA. One easy way to design any second-order DMA in a certain
number of directions, is to double the number of microphones and form an
equilateral triangle with three microphones on each one of its sides as shown
in Fig. 4.30. Therefore, with this two-dimensional array, we can realize all
second-order directional patterns at six different directions: 0 ◦ , 60 ◦ , 120 ◦ ,
180

◦ ◦ ◦

. Clearly, we can also combine other pairs of microphones
to realize all first-order directional patterns in many more directions.

, 240 , and 300

References

1. G. W. Elko, “Superdirectional microphone arrays,” in Acoustic Signal Processing for
Telecommunication , S. L. Gay and J. Benesty, Eds. Boston, MA: Kluwer Academic
Publishers, 2000, Chapter 10, pp. 181-237.
2. T. D. Abhayapala and A. Gupta, “Higher order differential-integral microphone ar-
rays,” J.Acoust.Soc.Am. , vol. 127, pp. EL227-EL233, May 2010.