3D Directivity Control of a Finite Cylindrical Loudspeaker Array with Cylindrical Harmonics

We propose a filter design method based on three-dimensional (3D) bases for a finite cylindrical loudspeaker array. In this method, we first derive the relationship between the 3D bases of directivity patterns and finite cylindrical harmonics. Directivity simulations were conducted using a prototypical 24-element cylindrical array with a radius of 0.07 m and height of 0.28 m and compared with the results of an 8-element circular array. These results showed that the cylindrical array can suppress sound pressure level of approximately 10 dB in the z-axis direction although the x-y plane was similar in comparison to the circular array. Moreover, we confirmed that the cylindrical array can control directivity in a diagonal direction.