A sound reproduction system is disclosed in which a sound barrier defines a horn passageway having a first end and a second open end. A high frequency range driver is provided at the first end, and is mutually coupled with a lower driver to the horn passageway. The lower driver has an upper frequency end lower than a frequency of a first cancellation notch for the drivers. The lower driver is located at a position along the horn passageway at which the passageway has a preselected cross-sectional area which is no greater than an area of a round cross section having a circumference equal to one wavelength at the upper frequency end.