Federal Signal's Modulator® Speaker Array Series consists of a family of six electronic sirens. These innovative omni–directional sirens are capable of producing high–intensity warning signals over a wide area. This efficient design enables these sirens to produce a high sound level, while making only moderate demands on the power source. Each Modulator Speaker Array is made up of aluminum modules that utilize four 100–watt drivers. Speaker arrays require a siren control unit\/battery cabinet (purchased separately). The Modulator Speaker Array provides a flat frequency response from 200 to 2000Hz for excellent voice reproduction or warning signals such as: Wail (attack), Pulsed Steady, Steady (alert), Alternating Steady, Alternating Wail, and Pulsed Wail – which are produced by the modulator siren control unit. Federal Signal's Modulator Speaker Array is intended for outdoor applications. Industrial sites such as refineries, chemical plants, power plants, or tank farms are typical applications for these omni–directional electronic arrays.