Acoustic lenses are structures that enable the focusing of acoustic waves, with increasing applications in audio devices like loudspeakers to concentrate energy toward a listening position. While typically employed at higher frequencies, achieving effective performance within the audible frequency range remains a significant challenge due to long acoustic wavelengths, which necessitate structures of substantially larger dimensions. This paper addresses the design of an acoustic lens dedicated to operation in the audible range. The proposed lens is composed of periodically arranged acoustic unit cells, enabling precise control over both the sound transmission coefficient; the phase delay. A parametric analysis of a single acoustic unit cell was performed, followed by global optimization of the complete lens structure using the Particle Swarm Optimization (PSO) algorithm. The outcome of the study is an acoustic lens design with predefined properties that demonstrate the desired directional characteristics. The findings highlight the potential of this approach for effectively manipulating the acoustic wave field; the directivity of sound sources within the audible frequency range.
