New for 2006, SoundOff Signal
has entered the full-size lightbar market. SoundOff has been making dash and package tray-mounted emergency lights, wig-way headlight flashers and other emergency vehicle modules for 30 years. Its new LED lightbar, the ETL-5000 was introduced in time for the Police Fleet Expo in Louisville, KY.
The SoundOff lightbar provides 360-degree coverage by the use of angled (or radiused) corner modules. Each of the four corner quadrants contains two LED modules. Of these, one is angled 30 degrees from the side while the other is 70 degrees from the side, both to the front and to the rear.
The SoundOff lightbar (of course) meets the photometric requirements SAE J845 and California Title 13. According to Phil Von Tom, director of business development, the beginning premise of the lightbar was that it meets the 360-degree coverage required by SAE J845 with just the four corner modules alone.
The LED colors currently available are red, blue, amber and white. The LED module in green will be introduced shortly. The new lightbar uses third generation LEDs, the OSRAM Dragon thin-film (red, amber) and thin-Gan (blue, white, green) LED series. Each of the individual LED modules on the SoundOff bar contains six LED lamps.
The SoundOff bar has room on the front for eight LED (or halogen) modules. It has the same eight-module capacity on the rear for a directional arrow. The rear options are designed around a five-module arrow, six-module arrow, seven-module arrow or eight-module arrow. The controller also allows the rear modules to be activated by the turn signal to double the turning intention. The rear LED modules do not have to operate as a directional arrow. They may also be flashed like the forward-facing LED modules.
The SoundOff LED module has two lenses. The inner, optic lens captures and funnels the light forward. The Total Integrated Reflectance (TIR) lens sets the initial reflected angle. Then the outer lens, either clear or colored, uses a relatively simple freznel pattern to make the LED light output more horizontal. The center of the lens has less of a pattern for more forward (on-center) light, while the outer part of the lens has more of a pattern for diffusing the light off-center. The outer lens in the inboard LED modules have less aggressive freznel patterns than the corner LED modules, which are designed to widely diffuse the light output. Clear or Colored Lenses
The ETL-5000 comes with either clear lenses or colored lenses. Some police departments want the colored lenses for a more obvious presence on the street. Lightbars with clear lenses have a lower visual profile...until they are activated, of course.
When colored lenses are specified, colored LED modules are still used, i.e., a red LED behind a red lens. The LED light source is monochromatic, i.e., only one color of light is produced. The red LED, for example, produces only the wavelength of red light. This red wavelength passes very efficiently through a red lens. The output losses are around 2% to 5%.
According to Mike Walma, electronics/optics engineer, the LED white light is a combination of all wavelengths of light. The red lens acts as a filter, blocking all wavelengths except red. This makes the use of a white LED behind a red lens very inefficient, with output losses around 50% and up. LEDs are very efficient at producing one color (wavelength) of light. LEDs producing the full spectrum of white light are not as efficient, and the light output not passed through the lens is converted to heat. Heat Dissipation
A significant engineering hurdle with LED modules is efficient heat dissipation. The LED light output decreases as temperature increases. Also, The emitted LED colors change (slightly) as the LED module heats up. To keep red from becoming a deeper red and amber from becoming orange, heat must be drawn away from the modules. Savvy fleet managers will check the color of the light from lightbars both as they are initially activated AND after an hour of continuous operation.
For this reason, the SoundOff bar makes extensive use of extruded aluminum heat sinks. The mother and daughter circuit boards and the LED modules are connected to aluminum for the best heat transfer. In fact, the main housing is one long extruded aluminum heat sink. The top cover and end caps are also aluminum.Takedown and Alley Lights
The lightbar uses halogen lamps, not LED modules, for both the front takedown lights and the side alley lights. White light has been the last LED color to develop, a slow and expensive process. The white LED has proved to be relatively successful for handheld and weapon-mounted flashlights. To date, however, most lightbars still depend on halogen for takedown and alley lights. The alley lights are 35-watt halogen bulbs, while the takedown lights use twin 35-watt bulbs in each module. Fully lit, the takedowns provide 70 watts of focused light.
The amp draw for halogen lamps is, of course, higher than LED modules. On the SoundOff bar, the halogen takedown lamps pull 7 amps each, and two lamps are used, for a total of 14 amps. The main LED modules, front and rear, draw 1.1 amps each in steady burn. The bar holds up to eight fronts and eight rears. The corner LED modules, and there are four, draw 2.2 amps each in steady burn.
Just to put the amp draw in perspective, with alternating front and corner LED lamps and sequencing rear LED lamps, the total LED amp draw is less than the 14 amps required for just the halogen take downs. The side alley halogen lamps pull 3.5 amps each.
Take down lights are NOT required on the ETL-5000. These two front spaces can be filled with LED modules. They can also be filled with blanks, which are silver in color to match the look of the bar. Flash Pattern / Rate Options
The SoundOff bar has one extremely important control feature...the Low Power Mode. With the LED modules pulsed at about 500 cycles per second rather than about 1,000 cycles per second, this mode reduces effective light output and effective amp draw, by 50 percent. No longer do we ask, Is the LED lightbar bright enough? Now, we often ask, Can you back off the brightness? Many patrol situations call for dimming the output. Back off the rear signal during a pursuit with other officers involved. Back off the front signal after the initial vehicle stop for the officer returning to the patrol car.
Interestingly, the lightbar also has a Cruise Mode. In this mode, the LED modules steadily “glow” for slightly enhanced vehicle visibility or office presence. In this steady-on mode, the LED module draws just 6% of the normal 1.1 amps.
The SoundOff ETL-5000 lightbar can instantly be switched between two selectable and programmable pattern modes. For example, the officer may want one flash rate and flash pattern for an emergency run, traffic stop or pursuit. This is Mode 1. The officer may want an entirely different flash pattern and flash rate for intersection crossing. This is Mode 2. Mode 1 and Mode 2 may have the same flash pattern but a drastically different flash rate. Or they may have the same flash rate, but a drastically different flash pattern. Or both…all at the officer’s fingertips.
The lightbar may also be programmed to flash either the takedowns or the alley lights in a predetermined pattern and rate. Some agencies include the white takedowns in their normal flash sequence. Others illuminate the alley lights at high profile stops like construction areas and lane blockages. Of course, the front LED lights can be flashed independently of the rear LED lights. The individual takedown lights can also be flashed as a part of an emergency light pattern. The SoundOff bar has at least 35 different flash and sequencing patterns.Adjustable Mounting Height
According to Gary Ludwig, senior product development engineer, the ETL-5000 was designed with aerodynamics as a major emphasis. This includes not only the shape of the lightbar, but also design of the unique mounting brackets. With form following function, the ETL-5000 was specifically designed for configurability and serviceability. While the LED modules are expected to require very little (if any) attention in their service life, the halogen bulbs may need replaced, as may outer lenses, exposed to the sandblast of road grit.
The SoundOff bar has unique and novel mounting bracket geometry. The lightbar can be adjusted for height! The lowest setting puts it about ¾-inch from the roof, a dimension that will vary depending on the arch or contour of the roofline. The highest setting places it almost 4 inches off the roofline.
The high position may be used on sedans to make the warning more visible in heavy traffic. The high position also makes sense on SUVs, where the roof height makes the warning signal difficult to see from vehicles close to the SUV.
In addition to a height adjustment, the lightbar has adjustable rubber support pads, which provides 2 degrees of up or down tilt adjustment. With the exception of the Dodge Intrepid, the B-pillar roof lines on all the current police sedans and special service SUVs is parallel to the ground within 1 ½ degree.
The SoundOff lightbar is 48 inches long, 10 inches wide and just under 3 inches thick near the ends. The center of the bar is just over 2 inches thick. Cleverly, the lightbar is designed to allow the cable to exit either the driver’s side or the passenger’s side of the housing.Beta-Site Testing
The ETL-5000 was beta-site tested by the Ottawa County, MI Sheriff’s Department. According to Lieutenant Steve Kempker, the SoundOff lightbar is popular among the officers, and highly visible in bright daylight. The lightbar, even mounted on an SUV, has excellent traffic moving and traffic clearing capabilities. The lightbar has very little wind noise at speeds up to 100 mph, and a great feature is the ability to adjust the height off the roof.
To complete its lightbar product line, SoundOff also introduced its more economical MTL-2000. This lightbar uses any combination of halogen and strobe lights, i.e., all-halogen, all-strobe or halogen-strobe mix. This is a more traditional lightbar for agencies not needing, or unable to afford, the advanced technology of LEDs.
SoundOff is solidly in the big league now with a robustly-designed, multiple-feature, well-thought-out LED lightbar.