Federal Signal Twinsonic

History

The Federal Signal Twinsonic light bar was the creation of Federal Signal’s lead design engineer Earl Gosswiller (1912-2009). Earl created the Twinsonic as a fully enclosed rotating beacon light bar that stretched across the roof of patrol cars in 1967. The Twinsonic debuted at the 1968 International Association of Fire Chiefs convention in Louisville, Kentucky. The light bar was an instant success with 400 being built in 1968 and 1969. Federal Signal also introduced the Model TS24 58-watt speaker to be housed inside the stainless steel enclosure.

Model 12 Series A1 & A3: The model 12 series A1 and A3 was a 54-inch full size light bar with (2) tall triple reflection single direction mirrors mounted next to the rotators. The first additions had black anodized aluminum frames and completely round bulb holders.

Model 12X: The next brain storm from Earl was the model 12X which took the (2) tall triple reflection mirrors and cut them horizontally and rotated the top half 180 degrees to face the rear. Now you had just as many flashes to the front as you did the rear.

Model 12F: The next product line was the 12F light bar which originally consisted of (4) PAR 36 (4414) bulbs mounted next to the rotators and these flashed in a wig wag pattern to the front and rear. By 1972 this was replaced by the new style 12F with lower front facing cascade mirrors and a top flasher housing with (2) polycarbonate filters made from cut down Dietz lenses.

Series A1: Featured metal speaker trays and both Series 1 and Series 2 motors. The series 1 motor has rounded sides and a flat top and bottom. This motor is assembled with stronger windings to reduce fatigue over time. The Series 2 motor had similar properties as the heavy duty Series 1 model but the castings were different. The second series had an X in the cast on the rear of the housing.

Model CTS: In 1972 Federal Signal entered into an agreement to build a special service bar to meet California Vehicle Code Section 25252 states that: “Every authorized emergency vehicle shall be equipped with at least one steady burning red warning lamp visible from at least 1,000 feet to the front of the vehicle. This model of light bar was the CTS series. This light bar featured a PAR 46 (GE 4001) steady burn red bulb on the inner driver’s side and a PAR 46 (GE 4478) mounted inner drivers side to the rear. This bulb was normally mounted in front of a cut out in the dome with an amber panel bolted and glued to the rear of the lens.

Small Models: By 1974 they came out with a “small” line of Twinsonic light bars that measured 47-1/4 inches in length. These were available in all the common models.

Economy Line: In 1974 they also came out with their Economy line which removed the stainless steel strips from the bar and replaced the stainless speaker cover with an aluminum one.

A3 Series: In 1974 they introduced the A3 Series line. This line featured natural color aluminum frames. They also switched to plastic speaker trays and the “skinny” bulb holders for the rotators.

In 1976 we see a change to the new series 3 motor. This motor is round in diameter and was not built to meet the same demands of the Series 1 and 2. The Series 3 motors were offered in the Twinsonic rebuild kits.

Medium Line: In 1977 Federal Signal introduced the “medium” line of Twinsonic’s which measured 47-1/2 inches. These light bars were available in all the common Twinsonic models.

Dual Motors: There were a small number of Twinsonic’s built with dual motors, but I don’t have any information for them. Allegedly the fleet manager at a police department was concerned that going from dual beacons with each having their own motor to a bar with only (1) motor would be a downfall for the Twinsonic. Federal Signal designed a dual motor setup for this agency. Others followed suit but the demand was not great. This option was apparently around a $70 option.

Bulbs: The Twinsonic had 30 or 60 Watt bulbs depending on the used color of the bulb. Clear & red are 60 Watt (GE#4464 & GE#4464R) and amber & blue are 30 Watt (GE#4416A & GE#4416B).

Biggest Production Years: The years 1976-1980 saw the biggest production years of the Twinsonic. These bars lost production numbers when the Aerodynic and Jetsonic light bars came into fruition. The last light bar according to Federal Signal was sold to the Pierce manufacturing company in August of 1984. It was sold to a department in South Dakota.

Federal Signal manufactured 30 different variations of the Twinsonic.

Twinsonic Model 12

The model 12 Twinsonic was the first fully enclosed light bar offered to the public. This light bar took the idea of the Visibar and placed the outer rotators under a large polycarbonate lens offered in different colors. The Model 12 has (2) full height triple step reflecting cascade mirrors which both face forward. The motor is mounted on the drivers side.

Twinsonic Model 12X

The Model 12X light bar was offered to the public in 1970. It features many of the same design ques from the Model 12 in that the outer rotators are housed under a polycarbonate lens, the motor is mounted on the drivers side. The difference in the Model 12X to the Model 12 is that the engineering at Federal Signal took the design of the tall 3-step cascade mirror and split it horizontally. They added a brace between the split mirrors and also had a stabilizing mount toward the inside rear corner.

The bottom mirror faces forward and the top mirror faces rearward. Many departments took these light bars and made the split mirrors both face forward. They often removed the metal brace between the mirrors. This metal brace became rare and I have re-manufactured them.

Twinsonic Model 12F

The Twinsonic Model 12F is based on the design of the Model 12. It features dual outer rotators under polycarbonate lenses and a drivers side motor. This model featured a five position terminal block with PWR, GND, SPKR and FLASHER

The first edition of the 12F offered inner mounted PAR 36 (GE 4414) bulbs, these were flashed left to right and front to back with a Tung-Sol 537 can flasher.

The engineers at Federal Signal were asked to create a second edition light bar with both alternating flashing lights and also forward facing 3-step cascade mirrors. They did this by taking a Model 12X lower front facing 3-step cascade mirror and adding a mounting base on top of it. they then fashioned a lens / lamp holder assembly. they mounted this same as the top mirror of the Model 12X and used a inner rear mounting stabilizer. They mounted a Tung-Sol 537 style can flasher and holder to the top mounting stud on the gear cage. The flasher is wired to a space on the terminal block and to each of the bulb holders. The lenses are cut down from Dietz. These lenses were offered in clear, amber, red and blue.

Twinsonic Model MEF

The Model MEF had rotating outer lamps with dual front and rear PAR 36 flashers. They also had a ‘V’ mirror that the Model EF did not have.

Twinsonic Model CTS (California TwinSonic)

In 1974/1975 Federal Signal was tasked with manufacturing a light bar to stay compliant with California Vehicle Code Section 25252 states that: “Every authorized emergency vehicle shall be equipped with at least one steady burning red warning lamp visible from at least 1,000 feet to the front of the vehicle. There is no code enforcement for the rear amber flasher. The designers at Federal Signal took a Model 12 light bar, removed everything from the frame except the outer rotators. They took the motor and gear cage apart, and re-assembled it on the passenger side. They also mounted a tall triple reflecting cascade mirror to the side as well. On the driver side they made a mounting plate for a front mounted PAR 46 (GE 4001) and a rear mounted PAR 46 (GE 4478). They installed a Tung-Sol 537 can flasher for the rear bulb and the front was a steady burn. The five position terminal block was labeled PWR RED, GND, SPKR, PWR AMBER. The motor, outside rotators and front steady red bulb were all together on the first screw. The rear amber flasher was separate.

The Multnomah County (Oregon) Sheriff liked the Twinsonic CTS bar so much that he ordered them for his cruisers. The light bars had blue lenses with the rear amber light cut out.

Twinsonic Economy

Federal Signal was approached by the towing industry to create a low cost light bar available to outfit their rigs. Federal came up with the idea to change the metal speaker trays to plastic. They also changed the stainless steel speaker cover to Aluminum. They deleted the stainless steel strips across the front or rear of the light bar. Taking these items away made the Twinsonic an economical light bar for this industry.

The first model was the Model 12E. This light bar had the outer rotators of the Model 12, it had the motor mounted to a plate on the drivers side. There were no mirrors or other lights mounted in it and it also deleted the passenger side mounting plate.

The Twinsonic Model 12EV was an economy series with a single ‘V’ mirror on each side which produced extra flash of light to the front and rear.

Twinsonic ‘S’ Small Series

Federal Signal created the “S” (small) 44-1/4 inch series light bar in the 1974. They created this light bar to offer smaller vehicles the ability to have the best light and sound product available on the market. The created a new frame with (4) breathing holes under the speaker. They also made a short speaker tray from metal and it was able to mount a TS24 under a shortened stainless steel speaker cover. The endcap of a small bar will be stamped with an ‘S’.

Twinsonic ‘M’ Medium Series

In 1976 Federal Signal created the “M” (medium) size light bar. This bar measured 47-1/2″ inches. You could get virtually any model in the M line. These light bars would have the designation M stamped in the endcap. These light bars had (8) breathing holes under the speaker cover.

Twinsonic 1981 Price List

The Twinsonic light and sound system set the standards for vehicle warning systems! It has two sealed beam rotating end lamps reflecting on inner mirrors, providing brilliant flashes of light warning. Models are available in single direction (front) or dual direction (front and rear). Choice of 12 or 24 volts.

Twinsonic Light And Sound System Full Size 54-Inch
Model	Description	Price
12	Twinsonic Tall Cascade Mirrors Facing Front 12-Volt	$446.00
12	Any Listed 24-Volt Applications Add+	$22.75
12Q	Same as above but with halogen style outer bulbs	$455.25
12E	Rotating outer lamps no inner mirrors or flasher	$334.00
12EF	Rotating outer lamps with dual front and rear PAR 36 flashers	$440.50
12EV	Rotating lamps with “V’ mirrors	$371.25
12F	Rotating lamps with front reflecting plus front and rear flashing	$511.25
12FQ	Same as above but with halogen style out bulbs	$531.25
12X	Rotating lamps with front and rear reflecting	$460.25
12XQ	Same as above but with halogen style outer bulbs	$489.75
CTS1	California style with front steady burn PAR 46, rear amber flashing PAR 46	$571.25
Twinsonic Light And Sound System Intermediate 47-1/4 Inch
12M	Twinsonic tall cascade mirrors facing front 12-volt	$440.50
12MQ	Same as above but with halogen style outer bulbs	$469.25
12MF	Rotating outer lamps with front reflecting and front and rear flashers	$506.26
12MFQ	Same as above but with halogen style outer bulbs	$529.25
12MX	Rotating lamps with front and rear reflecting	$456.00
12MXQ	Same as above but with halogen style outer bulbs	$487.50
12MEF012	Rotating outer lamps with dual PAR 36 flashers front and rear, aluminum grill	$444.11
12MEV012	Rotating outer lamps with ‘V’ mirrors and aluminum grill	$324.38
CTS1M	California style with front steady burn PAR 46, rear amber flashing PAR 46	$541.25
Twinsonic Light And Sound System Compact Size 43-1/2 Inch
12S	Twinsonic tall cascade mirrors facing front 12-volt	$437.75
12S	Any Twinsonic listed 24-volts application add+	$22.75
12SQ	Same as above but with halogen style outer bulbs	$447.00
12SF	Rotating outer lamps with front reflecting and front and rear flashers	$502.00
12SFQ	Same as above but with halogen style outer bulbs	$521.75
12SX	Rotating lamps with front and rear reflecting	$451.75
12SXQ	Same as above but with halogen style outer bulbs	$480.75
CTS1S	California style with front steady burn PAR 46, rear amber flashing PAR 46	$560.75
You must order one of the following to mount all Twinsonic models
12HK*3	Hook-On Mount	$113.25
12G	Gutter Mount	$113.25
12P	Permanent Mount	$103.00
12HG	High Gutter Mount	$116.75
EBK*3	Extension bar kit for above mounts for use on 12, 12F, 12X and CTS1	$36.25
Conversion kits for Twinsonic
GLCK	Gutter to Hook-On Kit	$85.25
DMCK	Dual Mirror conversion kit	$69.75
12XKF	Converts Model 12X to Model 12F	$84.75
12KF	Converts Model 12 with tall cascades to Model 12F	$119.50