Modulator model numbers identify the number of cells, as well as the number of drivers. When they were first made, they were used with Modulator Control Plus(MPC) and basic/standard Modulator Controls. Modulators that are being made now use the UltraVoice controller.
Due to the design of active cells, there would be unbalanced sound distribution without the inactive cell. Modulators have an inactive (dummy) speaker cell on the bottom of the stack that is used to help project sound in all directions. The modulator is composed of speaker cells (ranging from two to eight, with the exception of seven) that contain four speaker drivers per cell, although two models (model 60) had additional drivers available when they were still produced. The Modulator II is sold based on the more compact chassis of the siren compared to the original Modulators. They are identified mostly by their distinctive stacked 'flying saucer' design.
Electronic public warning siren A Federal Signal Modulator siren in Bay Head, New Jersey.įederal Signal Modulators (also known as Modulator Speaker Arrays) are electronic warning devices produced by Federal Signal Corporation that are used to alert the public about tornadoes, severe weather, earthquakes, fires, lahars, tsunamis, or any other disaster.
