A horn assembly for high frequency acoustic speakers. In an array of speakers, a spacing between adjacent speakers needs to be less than the wavelength of sound being emitted in order to combine effectively. For high frequency sound, a relatively small wavelength imposes a limitation on such a spacing. Such limitations are sometimes physically difficult to implement. A horn assembly increases the exit dimensions of the small speaker to larger desired dimensions by utilizing one or more plugs that divide a larger horn cavity into smaller horn cavities and creating similar pathlengths thereto. The similar pathlengths and the smaller horn cavities having desired dimensions allow the exiting sound to combine effectively. The overall dimensions of the exit portion of the horn assembly can be selected to match the dimensions of larger bass speakers, thus allowing improved arraying of the high frequency speakers with respect to other larger speakers.