Horn and horn driver two‐port measurements

Each installation of an electroacoustic aid to ship navigation has a unique requirement of sound pressure levels over geographical areas. To meet these requirements horn arrays. special horns, and baffles are required. Design is greatly aided by being able to predict the performances of horn‐horn driver combinations. A design method and measurement technique are reported here that characterize a horn by its driving point impedance at the throat, its transfer function of SPL at one meter to‐throat pressure, and its directivity characteristics. The driver is characterized by its electroacoustic two‐port parameters. Examples will be given where the electrical potential and power requirements can be predicted from the far field acoustical requirements. [This work was sponsored by the Ocean Engineering Division of the U.S. Coast Guard.]