Sound Column

a grouped acoustic radiator in the form of a linear, usually vertical series of loudspeakers of the same type that are connected cophasally and mounted in a common housing. The loudspeakers (usually electrodynamic) are mounted on a panel with openings and connected, through a common matching transformer and leads, to an electric audio-frequency power amplifier or a relay network. The panel and housing act as an acoustic baffle; the housing walls are usually damped to eliminate detrimental vibrations.

Sound columns are made with various output powers (2–100 watts) and numbers of loudspeakers (two to eight). Since the height is much greater than the transverse dimensions, the vertical directivity of a single loudspeaker is much sharper in the vertical plane than in the horizontal plane. Such a directional characteristic is suitable for the irradiation of large areas and enclosed spaces (stadiums and conference halls); in the latter it helps to reduce reverberation interference. Composite sound columns, which consist of two or three sound columns connected cophasally and mounted one above another, are used in cases where the directivity of the sound column’s radiation in the vertical plane is insufficient.