Loudspeaker arrays with high directivity are desirable in many acoustic and sound applications to direct sounds into a desired region. One way of designing such arrays is through the differential operator to maximize the directivity factor. However, this method generally works for linear arrays with endfire steering direction and its usage to generate a broadside radiation pattern is restricted to the second-order with three loudspeakers. This paper presents a general approach to the design of differential linear loudspeaker arrays with broadside radiation patterns of any-order. Three methods are presented to find the beamforming filter with design examples provided.