When it comes to lighting the road in front of your car or truck at night, most enthusiasts focus on light intensity instead of headlight bulb color. It’s straightforward to see the difference between yellowish light produced by incandescent halogen bulbs and the white/blue output of HID or LED bulbs. The science behind these light sources is interestingly similar to what professional car audio technicians measure to calibrate a digital signal processor in your mobile audio system. If you’re intrigued, read on, and we’ll explain in detail.

How Light Works

There have been many detailed scientific dissertations on how light works. These papers explain the electron and sub-electron concepts that allow us to see objects. In short, light is made of photons. Photons are packets of electrons that have been released from atoms. These packets of photons have energy and momentum but have no mass. This means you can shine a light at an object to illuminate it, but the energy from the light source doesn’t make the object heavier.

If we excite a group of atoms, the negatively charged electrons that orbit the nucleus absorb that energy. As more energy is added to an atom, the electrons circle faster and farther away from the center. When the energy source (electricity or heat) is removed, the electrons snap back to their original orbit path but release that added energy in the form of photons. Under specific conditions, the photons that are released produce visible light. If you studied electrical theory in high school, you’d recognize this pattern as similar to how electricity works. The only difference is that electricity involves electrons jumping from one atom to another to transfer energy.

When the light photons escape from an atom, they can have varying energy levels depending on the electron’s position when it leaves the atom. You can think of this as the photons having a specific resonant frequency. As a result, different types of atoms release photons of different wavelengths. The result is differently colored light sources.

Light and Color

We know that light sources have different colors. An incandescent bulb gives off a very different kind of light than a fluorescent bulb, a gas-discharge arc lamp (high-intensity discharge or HID) or a light-emitting diode (LED). Some light sources appear yellow, while others are white or blue. How these light sources illuminate objects can make them look very different.

Let’s take a giant step sideways. You’ve seen plenty of rainbows, but do you know what turns the supposedly white light from the sun into a color pattern that shifts from violet through to blue, green, yellow, orange and red? Water molecules refract the light from the sun. Because white light is made up of many different wavelengths, and each is reflected at a different angle as it passes through the water molecules, the light is divided into its primary components. Sorry, I know. We got all technical again.

An expensive-for-its-size electronic device called a spectral illuminance analyzer or a spectrometer can analyze the frequency content of a light source. The spectrometer works precisely the same way that a real-time audio analyzer (RTA) looks at the amplitude of the different sound frequencies produced by an audio source. As you may have guessed, we’ve added one to the BestCarAudio.com lab.

If you compare the two spectrographic measurements, you can see that the water vapor in the clouds is blocking increasing amounts of green, yellow, orange and red light. Unsurprisingly, we are left with a light source that makes everything look dull. This is because the water vapor in the air has quite literally filtered out the light energy that makes colors pop.

The software scales the measurement window to make it easy to see energy levels at different wavelengths. This is similar to the way our eyes or the iris and shutter on a camera work together to deliver a similar level of perceived brightness for a given lighting condition. The chart below shows both measurements overlaid, one on top of the other. You can see that the overall brightness level on a cloudy day is significantly lower.

The measured light level was 106,252 lux on a sunny day, whereas the cloudy day was only 9,069 lux. Converted to candlepower, the numbers are 9,874 and 843.

Headlight Bulb Color

When it comes to the headlights on your car or truck, bulbs come in various colors for a variety of reasons. At the incandescent end of the spectrum, most have a yellowish look. With that said, halogen bulbs (which use iodine and bromine gas) have less yellow and produce more light output than old bulbs that use argon. Here’s the spectrographic analysis of a relatively simple halogen light bulb.

As you can see, there is a lot of energy in the red portion of the light spectrum produced by this bulb. To be clear, it’s not an amber bulb, though; we should find one of those and test it as well.

OK, we’re back from the hardware store with a pair of Sylvania 3057AK amber turn signal bulbs. The graph below shows their spectral energy.

How we perceive the color of a light source is dependent on the frequency content of the energy coming from the bulb. Warm light will have more red energy, where a cool bulb will be bluer.

Color Temperature and Color Space

If you’ve ever shopped for HID headlight bulbs, you know their color is often described by a specific Kelvin value. For example, a yellow fog light bulb might be rated at 3,000 K, where a factory-installed HID or LED bulb might be a very pure white rated at 6,000 K. Those bulbs with a very blue tint are often up in the 8,000-10,000 K range.

Most people think these values are somewhat arbitrary, but the reality is, the light color can be measured with impressive accuracy using the right equipment. Our spectrometer can do this quickly and easily. The software will also plot the measurement on what’s called a color space chart. The chart outlines the level of red, green and blue in the light source and uses X and Y coordinates to describe the location on a chart. For our testing, we’ll use the CIE 1931 color space chart. The image below shows us where our measurement of the Wagner bulb falls.

The software tells us the Wagner light source has a correlated color temperature of 3,174 kelvins. As mentioned, that’s considered a warm yellowish light. The amber Sylvania bulb has a color temperature of 1,857 and falls into the orange and red portion of the light spectrum.

White Light Isn’t Always Made Up Of All Frequencies

The last item we’ll touch on in this article is a bit of a tease toward some future content we are working on. If you’re reading this, then you’re likely looking at a computer or smartphone screen. The light created by that screen is made up of tiny red, green and blue pixels. The colors you see depend on the intensity of each of those pixels. If the screen is to be blue, then only the blue pixels will be illuminated. For violet, the red and blue will be turned on. Yellow is produced by red and green. You can easily see this pattern by looking at the CIE 1931 color space images above.

What might be surprising to some is that the perception of white can be made up of specific amounts of red, green and blue light. The chart below shows a measurement of the light produced by the laptop screen on which this article was created.

Behold! Our Dell XPS 13 laptop screen is perceived as white, yet it’s primarily red, very light green and mostly blue light. Here’s how the white light it produces measures on the CIE 1931 chart.

Our screen has a correlated color temperature of 6,662 K. If we were scoring it on even whiteness, that’d be an excellent result. But does this score mean it’s a perfect source of white light? Absolutely not! We’ll leave you to ponder that thought as we prepare the next few articles.

Lead-in Image: Thanks to Josh Matthews for sharing this photo of an Acura RSX equipped with decidedly blue headlights.

This article is written and produced by the team at www.BestCarAudio.com. Reproduction or use of any kind is prohibited without the express written permission of 1sixty8 media.

As fall approaches, we find the sun setting hours earlier than it did in the summer. With this increase in darkness, we need to rely on the forward lighting systems in our cars and trucks to keep us safe. In this article, we are going to look at the importance of making sure your headlights are aimed properly. Proper horizontal and vertical adjustments will ensure that you can see far enough down the road to react to obstacles or avoid animals. Of equal importance, aiming your lights so that they aren’t blinding oncoming drivers is crucial to those drivers staying in their lane and not colliding with your vehicle. The science and process are simple, but they’re often overlooked.

Headlights Are an Important Safety System

In addition to your vehicle’s tires and braking system, your headlights are one of the most critical safety systems on your vehicle. If you can’t see far enough down the road when it’s dark, you won’t have time to react to objects in your path. At 60 miles per hour, you and your vehicle are covering 88 feet per second. Given than most humans have a reaction time of about one half of a second, and it takes another half of a second to move your right foot from the gas pedal to the brake, you’ve already traveled 80 feet. Now, consider that the average vehicle requires between 120 and 145 feet to stop from 60 mph, and you’ve likely traveled at least 200 feet.

Most low-beam lighting systems provide useful output to a range of 100 feet. Some of the better HID and LED systems are bright enough to illuminate 150 feet in low-beam mode. Driving at a speed where you don’t have enough time to stop because of your lighting system’s limits is called overdriving your headlights.

How Can You Upgrade Your Lighting System?

Upgrading the lighting on your vehicle involves two factors. First, you need a light source that is bright enough to illuminate the road at a distance that gives you enough time to react safely. Next, your lights need to be aimed perfectly to make use of their output capabilities. If your lights are aimed down at an angle of five degrees, then the area in front of your vehicle might be bright, but you’ll never see more than 100 feet down the road. Conversely, having your lights aimed horizontally might provide good long-distance vision, but this can lead to your lights blinding oncoming drivers. A driver approaching you who cannot see the edges of the road or your vehicle is as dangerous as you not seeing where you are going. Proper headlight aiming is paramount!

When Should I Have My Headlight Aim Checked?

The first sign that your lighting system needs adjustment would be that oncoming drivers are flashing their high beams at you as they approach. Blinding an oncoming driver is extremely dangerous. Likewise, if your lights don’t light up the rear bumper of a vehicle a car’s length in front of you, they need adjustment.

If you have made any modifications to your vehicle, you should have your technician check the headlight alignment. Changes to tire diameter or suspension height, especially if you have installed a leveling kit or lowering springs, require that the lights be adjusted. If you have added weight to your vehicle in the form of a stereo upgrade with a subwoofer system, the additional mass in the rear of the vehicle may also necessitate a change in light aiming.

Let’s Talk About Headlight Aiming Angle

The farther your lights are above the road, the steeper they can be angled downwards while still allowing you to see approximately 150 feet in front of the vehicle. Many websites cite a specific angle that is deemed to be suitable for all applications. The reality is, the specific downward angle of the beam depends on their distance above the ground. If someone says two degrees is the right angle, but your lights are 18 inches off the ground, you’ll only have light for 43 feet in front of your car. If you have a truck with the lights 36 inches above the ground and set the lights to the same angle, you’ll have light for 86 feet. Likewise, the suggestion that a fixed amount of drop is suitable also fails to compensate for differences in bulb height off the ground.

Have Your Headlights Adjusted for Maximum Safety

When it’s time to have your headlights adjusted, we’ve developed a simple process that makes the adjustment reliable and efficient. Before the technician begins any work, your vehicle must be on level ground with the tires inflated properly. Ideally, whatever combination of driver and passenger(s) is most common to the vehicle’s operation should be inside. Likewise, the fuel tank should be half full. If you have a truck or SUV and carry tools or supplies, have them in the vehicle. You’ll want the ride height to be typical before the measurements begin.

Step 1 – Measure the Cut-off Height

The first step is to establish the level at which the light is produced at the bulb or lens. With the vehicle appropriately loaded (as outlined above), measure from the ground to the top of the light cut-off pattern as close as possible to the headlight lens. Note this measurement for each side of the vehicle, as it may not sit perfectly parallel to the ground.

This process requires that the lights are already aimed relatively accurately. If you’ve had new projectors or bulbs installed, your tech will need to make sure the light pattern is relatively close to accurate. If a light is pointing at the sky, the remainder of the measurements will be inaccurate. They should be within a few degrees of horizontal.

Step 2 – Measure the Cut-off at 25 feet

The next step is to measure the height of that headlight cut-off at a distance of 25 feet in front of the lights. Use the same reference point used for the first measurement to set this distance. For example, if the tech measured the at-vehicle height 4 inches in front of the headlight lens, he or she should measure out 24 feet and 4 inches for this second measurement.

Step 3 – Use the Chart

Using the chart below, your technician can determine how high the cut-off should be above the ground for the distance you want to illuminate. If you drive exclusively in the city, then the 125-foot distance will work well. If you drive in the country, the extra distance afforded by using the 175-foot measurement is a better choice.

Step 4 – Adjust the Lights

Most modern vehicles have simple adjustments for vertical and horizontal alignment built into the light assembly. In most cases, a long screwdriver is all that’s required to raise or lower the light aiming to achieve the correct cut-off height.

The next step is for the technician to adjust the lights so that the drop at the 25-foot mark matches the chart. As long as both lights are close to each other in height, your technician can fine-tune the adjustment by lowering whichever light is higher so that the top of the cut-off is in line with the output pattern of the other light.

Horizontal Headlight Adjustment

If work has been done to the vehicle or the light assemblies, then your tech may need to adjust the horizontal adjustment to make sure both lights are aimed forward and that the hot spots from each light are spaced apart by the same distance as the bulbs in the vehicle. It’s crucial to make sure the lights are pointed straight ahead and not off to the left or right.

Drive Safely with Proper Lighting

There are a multitude of options to upgrade the lights in your car or truck. High-performance halogen, LED and HID bulbs can improve the capabilities of mediocre factory lighting systems. Once you’ve had these light upgrades aimed properly, you’ll be able to see farther and drive more safely. Your local specialty mobile enhancement retailer can likely help you with a complete lighting solution that includes proper pattern alignment.

This article is written and produced by the team at www.BestCarAudio.com. Reproduction or use of any kind is prohibited without the express written permission of 1sixty8 media.

Custom lights and LED strips have been a staple for car upgrades since the Fast & Furious days. Whether it’s a strip of blue, green or red lights in the footwells or a complete custom amp rack or center console, lighting can add personality, style and flair to your vehicle. Let’s look at some options for adding lights to your car, truck or motorcycle.

A Subtle Approach to Lighting

Sometimes all it takes is a small strip of lighting behind a switch panel or around an amplifier to make a relatively simple upgrade look fantastic. Integrating lighting into your vehicle isn’t as simple as running some wires. The locations for the lights and how their output will be diffused to provide a smooth look is part of the design and construction process. The end results are typically worth the effort.

Lighting in Audio System Components

The most common place where lighting is added to cars and trucks is when a custom amp rack or subwoofer enclosure is being built. Highlighting the equipment or adding a little style to the install with RGB LED lighting is a great way to make the vehicle stand out.

Exterior and Under-Vehicle Lighting

Thankfully, the days of real high-voltage neon tubes under cars and trucks are long behind us. Compact LED light pods and RGB strip lighting can be fit into tight spaces, and their compact size helps to protect them from damage. In terms of durability, LED lighting is solid-state. There are no glass bulbs or lenses to worry about. LED lighting also runs cool, so there’s no risk of heat damage.

Shopping for Lighting Upgrades

It should come as no surprise that lighting upgrades vary in cost by the complexity of the project. A strip of solid-color lighting under a dash or seat is a lot less work than cutting acrylic with a laser and integrating a housing for a light strip in a custom console. If these amazing photos have motivated you to add lighting to your vehicle, drop by your local specialty mobile enhancement retailer and ask them about your project.

Thanks to Adam Coffman from Tampa Autobody and Audio in Tampa, Florida, for the photo of the custom Slingshot we used as the header image.

This article is written and produced by the team at www.BestCarAudio.com. Reproduction or use of any kind is prohibited without the express written permission of 1sixty8 media.

Upgrading the headlight bulbs or assemblies on your car or truck is a great way to improve your ability to see long distances while driving. Though many buyers focus on the amount of light produced by the bulb, ensuring that the new solution provides a proper beam pattern is crucial to your safety and that of other people on the road. Let’s discuss beam patterns and their implications for long-distance vision.

Parts of a Headlight Assembly

There are two popular types of headlight assemblies: projector and reflector styles. A reflector headlight assembly typically features a large metallic bowl that surrounds an incandescent bulb. The shape of the bowl is designed to focus the light from the bulb in a relatively narrow beam. In a projector assembly, the bulb is placed in a compact bowl that’s 2 or 3 inches in diameter. A relatively thick lens on the front of the assembly focuses the light. These designs often include a metal plate between the reflector and the lens to provide a sharp cut-off that keeps the output from blinding oncoming drivers.

Different Bulb Upgrade Options

When shopping for upgraded bulbs for your lights, you have the option of high-output halogen, HID and LED. In the incandescent halogen market, bulb sets like the Osram Night Breaker Unlimited, Sylvania Silverstar Ultra and GE Nighthawk Platinum can increase light output by as much as 29% over a standard halogen bulb. When it comes to HID kits and LED bulbs, there are quite literally thousands of options. It is worth keeping up with reputable review websites and YouTube channels to see how technology is advancing. As of this writing in early 2020, there are finally LED bulbs that provide more light output than a 35-watt HID kit.

What Does More Output Mean?

Ignoring the importance of beam pattern for just a minute, more light output means that whatever beam pattern is created will be brighter. Does this automatically mean you can see farther? Well, if your headlights aren’t adjusted properly, then no. Imagine if your lights are angled down a bit too much. All that light will only make the area in front of your vehicle brighter. Logic dictates that you should aim your lights a little higher in order to see farther. While this makes sense, you now run the risk of blinding oncoming drivers. This practice is extremely dangerous and could lead to you getting a ticket from the police.

What Is Headlight Beam Pattern?

Every light source emits light in a pattern. A candle, for example, produces a relatively spherical light source, lighting the area to the sides and above evenly. If you put a mirror beside the candle, you bounce that light out evenly in all directions.

If we now look at a flashlight, you can see that the light output pattern is more of a cone than a sphere. Little to no light is radiated behind or directly above, below or to the sides of the flashlight. Understanding this is fundamental to understanding how headlights work.

The headlights in most North American vehicles are designed to focus light in what is called a DOT pattern. This pattern, most commonly visible with projector-style light assemblies, has a sharp and defined upper cut-off that prevents oncoming drivers from being blinded. The pattern includes a step around the center of the output to put more light on the road on the right, so you can see farther without affecting oncoming traffic.

Light Intensity within the Beam Pattern

While the upper cutoff is crucial to keeping you and the other drivers on the road safe, the amount of light in different parts of the output pattern is also crucial. For optimum long-range visibility, you will want a relatively small and focused hot-spot in the upper center of the pattern. If there is too much light around the middle of the pattern, the road directly in front of the vehicle may be too bright, causing the iris in your eyes to contract slightly and reduce your long-distance vision.

How to Choose the Right Headlight Upgrades

If you are dealing with a reputable mobile enhancement retailer, ask if they can test-fit the planned light upgrade in your headlights before you finalize the purchase. Look at the light output on the wall of the shop and compare it to your factory lights. Make sure that any cut-off remains sharp and that the hot spot remains centered.

This article is written and produced by the team at www.BestCarAudio.com. Reproduction or use of any kind is prohibited without the express written permission of 1sixty8 media.