Patent ID: 8406445

Claim:
A loudspeaker system having an operating frequency range comprising a high frequency channel, a low frequency channel, a horn in said high frequency channel, said horn having and mouth end, a throat end, expansion walls between the throat end and mouth end, a center radiation axis, and an inherent cut-off frequency below which the horn by itself loses vertical beamwidth control, a high frequency transducer coupled to the throat end of said horn, a low frequency transducer in said low frequency channel, said low frequency transducer having a center and being positioned in spaced relation to the mouth end of said horn so that there is a defined separation between the center of said low frequency transducer and the center radiation axis of said horn, and a signal processing circuit, said signal processing circuit including a high frequency channel for driving the high frequency transducer coupled to said horn and defining in-part the high frequency channel of the loudspeaker system, and a low frequency channel for driving the low frequency transducer and defining in-part the low frequency channel of the loudspeaker system, said signal processing circuit having at least one first order and at least one second order cross-over circuit portion in the high frequency channel and in the low frequency channel thereof, said cross-over circuit portions combining to produce a cross-over frequency region below the cut-off frequency of said horn, such that the horn and low frequency transducer interact to contribute acoustic outputs within said cross-over frequency region to extend the operating frequency range of the horn below the inherent cut-off frequency of the horn, said signal processing circuit further having equalization circuit portions in the high frequency channel and in the low frequency channel thereof for equalizing the acoustic output of the loudspeaker system, including equalizing said acoustic output in the cross-over frequency region, the expansion walls of said horn being designed to provide relatively constant horizontal and vertical beamwidths within portions of the operating frequency range of the loudspeaker above the cross-over frequency range thereof, and portions of said signal processing circuit, including the cross-over circuit portions in the high and low frequency channels thereof, being designed to provide vertical beamwidth control of the acoustic output of the loudspeaker system within the cross-over frequency region thereof.