A new family of horns is presented, the Hybrid Constant Directivity (HCD), investigating some practical aspects of constant directivity design through real and FEA simulated 3D prototypes. Horn driver SPL simulations are conducted using a method already presented to the scientific community and here improved, lead to a minimum mismatch between horn directivity simulations and measurements. A detailed numerical match of the beam-width is examined with a direct SPL comparison among exponential, tractrix and spherical horn expansions. Therefore, horns aspect ratio is changed, obtaining HCD elliptical and rectangular mouth horns referenced and correlated to the circular one SPL simulation. Also wave-front shapes, mouth diffraction effects and radiation impedances are analyzed. Finally, the mathematical model for calculating HCD horns is disclosed.
