Furthermore, experiments have also shown that for a given fixed microphone spacing, increasing the number of microphones reduces the acoustic bandwidth of the array [9]. In other terms, as the number of microphones increases, the array becomes more frequency selective, and picks a smaller frequency range in a given direction. This means that we will have to choose the number of microphones, large enough to provide a narrow directivity, and small enough to provide a bandwidth that accommodates the human voice range.