Modulator

	Federal Signal Modulator Federal Signal Modulator II
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Company	Federal Signal Corporation
Produced	1990-2013 (Modulator) 2013-present (Modulator II)
Type	Omnidirectional Electronic
Sound output	106-125 dB @ 100 ft
Wattage	400-4800 W (Modulator) 400-3200 W (Modulator II)
Voltage	24/48 V DC
Preceded by	Federal Signal EOWS
Documentation	Manual

The Modulator is an omnidirectional multicellular electronic siren produced by Federal Signal and is Federal's best-selling electronic siren, able to be found all across the world. Taking inspiration from Whelen's multicellular sirens such as the WPS-2700 and WPS-2800, these sirens are well known for their unique cellular design which allows for true 360° coverage. They are sold alongside Federal's DSA electronic siren, and the ECLIPSE⁸, 2001-130, and 508-128 mechanical sirens.

History and Design

Modulator (1990-2013)

The Modulator was introduced in 1990, directly replacing the EOWS*1212 as Federal's standard omnidirectional siren. Rather than using a standard array of speakers, the Modulator instead makes use of a multicellular design, supporting up to 7 elliptical aluminum cells per siren. Each cell contains 4 100 W speaker compression drivers, and up to 6 active cells can be added to the siren. Every Modulator siren has a "dummy" cell at the very bottom, which contains no drivers and is only there to spread the sound from the bottom active cell evenly. Early Modulator cells were made of fiberglass before aluminum became the standard by the late 1990s. Fiberglass became a special-order option until it was discontinued in the mid-2000s. Modulators with fiberglass cells are given the "B" suffix on the tag.

Each cell is attached to a conical support, which along with the shape of the cell helps spread the sound in a perfect 360° radius. The sound is projected out of the bottom of each active cell. Each driver is attached to the cell from the outside, attached to small panels held on by 4 screws. This allows for easy replacement of blown or defective drivers by hot-swapping them with new drivers. Special variants of the Modulator allowed for additional drivers per cell, including the 3024H, 6032, and 6048. The 6048 requires an additional controller due to the number of amps it requires.

Modulators are very large sirens, with the 6024 and its variants towering over an average person. Modulators originally came with the MC controller, and later the MCP and UltraVoice controllers. Modulators are also compatible with other companies' controllers. The Modulator is voice-capable, both with prerecorded messages and local input. The original Modulator would be discontinued in 2013, being replaced by the Modulator II. The Modulator is an incredibly popular siren and can be found all across the world as a nuclear, tsunami, weather, or plant siren, as it excels in a multitude of roles.

Modulator models

Model	Decibel rating (100 ft)	Drivers
MOD1004	106 dB	4
MOD2008	112 dB	8
MOD3012	115 dB	12
MOD3024H	121 dB	24
MOD4016	118 dB	16
MOD5020	120 dB	20
MOD6024	121 dB	24
MOD6032	123 dB	32
MOD6048	125 dB	48

Modulator II (2013-present)

In 2013, the Modulator II, or B series, was released, intended to be a far more compact version of the Modulator which improved on the design. Rather than using large elliptical cells, the Modulator II instead uses shorter, narrower cylindrical aluminum cells. This allows the siren to be more compact than its predecessor and allows it to have even more cells than before. The Modulator II now supports 1-8 active speaker cells, on top of the bottom dummy cell, with each active cell having 4 100 W speaker drivers. The Modulator II no longer supports a 48-driver model, as the brand-new 8032B nearly matches it in performance without the need for a second controller. However, the 6032 is still available as the 6032B. The 3024H was also discontinued, being replaced by the 4032B. The 4032B contains twice as many drivers per cell as the 4016B.

The Modulator II models are nearly identical in performance to their predecessors, with only the 8032B differing from the 6032's performance. The Modulator II is also voice-capable. Modulator IIs can come with an optional set of red lights on the dummy cell, which gives a visual alert that the siren is operating for those who cannot hear it. The Modulator II comes standard with Federal's UltraVoice controller. The Modulator II, like its predecessor, is very popular and can be found all across North America. Every siren in the Modulator II series is given the "B" designation. Its main competitors are Whelen's WPS-2900 series, ASC's i-FORCE, and ATI's HPSS series.

Modulator II models

Model	dB @ 100 ft	Drivers
MOD1004B	106 dB	4
MOD2008B	112 dB	8
MOD3012B	115 dB	12
MOD4016B	118 dB	16
MOD4032B	124 dB	32
MOD5020B	120 dB	20
MOD6024B	121 dB	24
MOD6032B	123 dB	32
MOD8032B	124 dB	32

Examples