This research program concerns on advanced techniques for the electro acoustic line arrays development. Line array is a well know structure; its linear setup gives particular characteristics to the sound field: in fact, the introduction of a digital system control allows the directivity improvement, emphasizing the direct emission and minimizing the secondary reflections. For these reasons, the use of a line array is especially suitable for highly reverberant environment such as conference rooms, churches and airports.
In this program, a3Lab has developed a lowpass filter based algorithm which allows the pointing of the sound beam, whose amplitude is constant with respect to the reproduced frequency. Furthermore, the developed algorithm allows the sound beam digital pointing without introducing of any mechanical movements: this is a great advantage in terms of both easier wall mount and direct field reinforcement. The correct pointing is guaranteed by the introduction of fractional delays filters. The introduction of fractional delays improves the correct digital pointing. The software has been developed in the Matlab framework. Several tests have been carried out using a prototype, composed of 16 loudspeakers, in a highly reverberant environment. These tests have showed good results in terms of both polar responses evaluation and subjective listening.