A Look at Series and Parallel Subwoofer Wiring

It seems do-it-yourself installers have taken a liking to our discussion about wiring multiple subwoofers to a single amplifier. The popularity makes sense, since many car audio enthusiasts aren’t familiar with series and parallel wiring. A question came up on Facebook a few weeks ago asking if it was better to wire a pair of dual voice coil subwoofers in series with their coils in parallel or vice versa. We thought it might be fun to turn that question into yet another experiment and dive deep into the options of series-parallel wiring.

Wiring Dual Voice Coil Subwoofers

Unless your installer has access to some very low impedance subwoofers, most installations will see the subwoofers you have purchased wired in parallel. For example, say you’ve chosen a pair of 10-inch subs with dual 4-ohm coils. In that case, your installer could wire all four coils in parallel to present a 1-ohm load to a monoblock subwoofer amplifier. What if you’re after a solution that will offer the best sound quality possible, and you’ve chosen a two-channel Class-AB amp to power your subwoofers? In most cases, these amplifiers want to see a 4-ohm load when bridged. It’s not difficult to wire a pair of dual 4-ohm subwoofers to present this load, but there are a couple of options.

Series the Coils’ Woofers on Each Driver, Parallel the Subwoofers

Your installer’s first option is to wire the voice coils on each subwoofer in series. For our dual 4-ohm subwoofers, this wiring configuration would add the voice coil impedance on each driver to produce a nominal 8-ohm load. Next, your installer would wire each subwoofer in parallel with your amplifier to create a 4-ohm load.

Woofer Wiring — A pair of dual-voice-coil subwoofers wired with their coils in series and the subwoofers wired in parallel to the amplifier.

Parallel Each Woofer’s Coils, Series the Subwoofers

The second option is to wire the voice coils on each subwoofer in parallel, then wire the two subwoofers in series with each other to the amp. Each subwoofer would have a net impedance of 2 ohms, and wiring those loads in series would present our amplifier with a 4-ohm load.

However, our subwoofers aren’t resistors. We talked about the reactive characteristics of speakers and subwoofers not long ago in this article. Since we’re dealing with inductance and capacitance along with the resistance of the voice coil, is there a chance that the two wiring options present different results in terms of performance? Let’s see what happens!

Let’s Do a Test!

We have a pair of 10-inch subwoofers that we’ve meant to install into the sound system in our office. Yes, we need the ability to reproduce 25 Hz with authority while watching Cleetus McFarland, AvE, Project Farm and bigclivedotcom on YouTube. OK, maybe we don’t NEED it, but we want it. As we described in our examples above, the subwoofers have dual 4-ohm voice coils, so they’ll be perfect candidates for our experiment.

First, we measured the Thiele/Small parameters of one subwoofer using our new Clio Pocket 1 portable measuring system. Next, we measured the sub with its voice coils wired in series and then again with the coils wired in parallel to generate the data below.

Not surprisingly, the mechanical characteristics like resonance frequency (Fs) and compliance (Vas) didn’t change. As we expected, the electrical measurements like DC resistance, electrical Q, and inductance (at 1 kHz) did change.

Electromechanical Series-Parallel Wiring Results

Next, we wired the subwoofers together in the configurations we showed in the two diagrams at the beginning of the article and repeated the measurements to see what, if anything, had changed.

We’ll start by saying that the differences are minimal. The reality is, the system will work just fine wired either way. With that said, there are signs that wiring the coils on each sub in series and wiring the subwoofers in parallel is slightly beneficial.

If you look at the chart above, the DC resistance of the C-S W-P configuration is a little lower, as is the driver’s total Q (Qts). A lower Q-factor can mean less resonance at Fs and a more accurate bass response.

Sometimes an experiment yields earth-shattering results. Other times, the outcome is subtler or less controversial. Most professional installers wire coils in series and those subwoofers in parallel. If you need a hand choosing suitable subwoofers for your car audio system or help in wiring them, drop by your local specialty mobile enhancement retailer today.

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.

Understanding the Science Behind Automotive Headlight Bulb Colors

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.

Headlight Color — Our friend Jeremy Lambertson from Driven SS in Marquette, Michigan, and his wife, Carrie, snapped this photo of a rainbow after a Cars and Coffee event.

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.

What Is the Big Three Electrical Upgrade?

We were recently at an event that was hosting a mobile audio system SPL competition. If you aren’t familiar with this sort of thing, it’s a contest to see who has the loudest stereo. We aren’t talking about cranking the dial on the factory radio. Instead, some of these folks build steel and concrete reinforced subwoofer enclosures and feed tens of thousands of watts to their subwoofers.

As you can imagine, delivering that much power requires significant electrical system upgrades. Many of these creations have multiple alternators and huge banks of batteries. If you’ve upgraded your car or truck with an amplifier that can produce hundreds of watts to your speakers, there’s a wiring upgrade called the Big Three that can improve the efficiency of your electrical system. Let’s look at what this upgrade is and why it’s a great starting point for a high-power car audio system.

How Automotive Charging Systems Work

The first thing you need to know about delivering power to your amplifier is that most of the energy will come from your alternator, not the battery. The battery is there to start the car. Once a vehicle is started, the alternator, which is mechanically driven by the engine, provides power to replenish the battery for the next start. The alternator also runs the computers, ignition system, fans and lights in your vehicle. Once you’ve started the vehicle, you could remove the battery and everything would, under normal conditions, operate just fine.

This scenario changes if you add a high-power amplifier to your vehicle. Say you have a 1,000-watt amplifier and you want to deliver that full amount of power to a few high-power subwoofers. At 13.8 volts, most amplifiers of this type will consume about 100 amps of current. If you have the engine running, headlights on and a climate control system in operation, your car or truck may be using 30 or 40 amps of current to power those systems. If the alternator is only rated to produce 80 amps, there certainly won’t be 100 amps left for your stereo.

The additional current the amplifier wants will come from the battery, albeit at a lower voltage. You will likely find that an amplifier rated for 1,000 watts at 14.4 volts can only produce about 800 watts at 12 volts without clipping the output signal and adding significant distortion.

Big Three — When upgrading, make sure the retailer working on your car or truck uses all-copper, full AWG-spec power and ground cables like those from Rockford Fosgate.

How To Make the Most of Your Alternator

The first step in optimizing the electrical system in a car or truck is to reduce waste. In this case, waste is the power converted to heat because of resistance in cables and connections. First, have a look at your alternator and battery. How large are the wires running to and from them? Unless you have a big truck with a high-output alternator, chances are that the wiring is 4 or maybe even as small as 6-AWG.

Please make no mistake about it, the company that built your car or truck deliberately chose the smallest, lightest and least expensive wire that would allow the vehicle to function reliably. They had no intention of providing conductors that could handle two to three times what the alternator was rated for.

The Wiring Upgrades that Make the Difference

The Big Three upgrade involves adding to or replacing the existing conductors with larger, high-quality wires. The upgrades in the Big Three are:

The run from the alternator chassis to the negative terminal of the battery.
The run from the output of the alternator to the positive terminal of the battery.
The ground connection from the negative terminal of the battery to the chassis of the vehicle.

Depending on your vehicle, there may be other wires that can be upgraded at the same time. For example, if there is a main power distribution box under the hood, running new wire to it can help provide more voltage to the factory-installed electrical and electronic components in your vehicle.

Another upgrade you may want to make at the same time is replacing the battery terminals. Some factory-installed terminals are notoriously flimsy. If you’re demanding significant current from the battery, then optimizing each component along the way only makes sense.

Is the Big Three Enough?

In 2012, we wrote an article about upgrading the stock electrical system wiring in modern cars and trucks. Even though it was a decade ago, new vehicles at the time were being constructed out of materials like QuietSteel and aluminum, and some companies had started using adhesives instead of spot welds to bond unibody panels together. All of these advances in vehicle assembly work against our desire to deliver large amounts of current to an amplifier, especially when we want to use the body as the ground return path.

Power delivery from the positive terminal of the alternator is as important as the ground connection to the chassis and battery. If the current can’t flow through both, you are wasting energy by transforming it into heat. Upgrading and adding grounds with the Big Three is a start. If you are serious about optimizing your electrical system, then you’ll want to add a ground wire from the battery or alternator directly to your amplifier. Back in 2012, we called this the Big Four.

Full disclosure: This wasn’t our idea. The first we heard of running a dedicated ground wire was when we were checking out Precision Power’s fleet of Chevrolet Suburban demo vehicles back in the ’90s. The topic came up again when Ford introduced QuietSteel in the F-150 vehicles, and companies were having problems with amplifiers failing because of low voltages. As a solution, JL Audio suggested adding what they called a parallel ground. This wire would connect to a conventional ground point in the rear of the vehicle and run to the battery’s negative terminal or the alternator. A benefit of the parallel ground is that it offers less resistance than a dedicated ground wire or using the chassis. As a result, current can flow through both paths, reducing the voltage drop and improving system performance.

Optimize Your Vehicle Electrical System

If you’ve purchased a high-power amplifier for your vehicle, talk to your local specialty mobile enhancement retailer about upgrading all the wiring in the electrical system. Implementing an upgrade like the Big Three or, better yet, the Big Four will allow the amplifier to produce more power and allow the system to play louder with improved reliability and efficiency.

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.

Let’s Talk About Remote Starter and Security System Range

Range is the critical factor in the quality and performance of a remote car starter or security system. That’s the distance between you and your vehicle when you’re sending a lock, unlock or remote start command, or are hoping to receive a security notification. If you aren’t close enough, or the convenience system doesn’t have enough power, signals may not reach the vehicle or the remote.

Remote Starter and Security System Key Fobs

The handheld remote that comes with your vehicle or an aftermarket starter uses radio frequency communication to transmit commands. These work in a similar fashion to a radio station in that they broadcast in a circular pattern from the remote. If your vehicle is close enough and the signal is strong enough, the receiver in the car or truck will relay the command to the control module and execute the function.

Let’s look at two-way remote controls. A two-way remote sends a command such as “unlock” to the vehicle when you press the button. When the command has been received and the doors are unlocked, the transceiver in the car sends a command back to your remote to let you know the request was executed. The benefit of this two-way communication is that you always know the status of your car or truck. There’s no need to guess whether the doors are locked or the engine is running.

Remote Range — Two-way remotes like the new Compustar R5 allow security warnings from the car or truck to alert you when something is wrong.

How Do Remote Car Starter Companies Define Range?

No matter which brand of convenience or security system you’ve chosen, they all try to describe the distance between the vehicle and the remote in a measurable range. The simplest aftermarket remotes usually offer about 1,000 feet (about 300 meters) of range under ideal conditions. The step-up systems provide solutions that work at ¼ mile, 3,000 feet (914 meters) or 1 mile (1.61 kilometers). Some companies offer ultra-long-range radio frequency remotes that can deliver 2 or even 3 miles of range.

All manufacturers of remote start systems calculate these distances based on ideal controlled conditions. With trees, houses or buildings between you and the vehicle, the maximum functional range will decrease dramatically. If you’re inside a building (apartment, office tower, factory, hospital, etc.), that will decrease the effective range. A lot of electrical interference from communication systems will also reduce the usable range. We’ve seen cases where a specific remote solution worked great in one city but barely worked at all in another because a nearby military base was broadcasting something in the same frequency range.

To compare remotes, consider their power levels. The simplest 1,000-foot models could be your distance benchmark. A remote that offers 3,000 feet of range isn’t just three times more powerful; it’s closer to eight times as powerful. Because the signal radiates in a circular pattern, the power level needs to be about four times stronger to double the distance. That would mean a transmitter needs to be 16 times stronger to quadruple the effective distance. So, a remote that offers 1 mile of range is just over 25 times more powerful than one that only provides 1,000 feet of functionality. The 2-mile remotes are 100 times more powerful than the 1,000-foot models, and 3-mile units are an amazing 223 times more powerful.

Manufacturers of remote start and security systems work to increase range in other ways. The first is to switch from amplitude modulation (AM) signal to frequency modulation (FM). As you may have noticed on your car radio, FM offers better noise rejection than AM. The second method to improve range is to use what’s known as frequency-hopping or spread-spectrum communication. A simple way to understand this is to think of spread-spectrum systems as a group of people yelling a command rather than a single person. If there is noise interfering with one person yelling, the message from one of the other people is still likely to get through.

Why Is Remote Range Important?

If you park your car in the driveway of your house and want to start it before work, you don’t need much range. A 1,000-foot system will likely be more than adequate. If you’re in an apartment on the fourth or fifth floor and the car is parked below you, the same applies. However, if you live on the other side of that apartment building, you’ll need to send a much stronger signal.

Think, too, about where you work. Do you work in a small office where your car is parked outside the window? If so, 1,000 feet is lots of transmitting strength. What if you work in a hospital, a distribution warehouse or a manufacturing facility and your car is 1,500 to 2,000 feet away? There may also be mechanical and electronic equipment along with the metal structure of the building between you and the vehicle. You may need 20 or 50 times as strong of a signal to let you start the car.

Logically and not incorrectly, you could wait until you were at the door to the parking lot to start your car and let the air conditioning run in the summer or get the heater working in the winter. However, if it’s the latter, the car won’t warm up much in the two or three minutes it takes to walk across the parking lot. The whole purpose of a convenience system is to make the vehicle more comfortable when it’s time to drive away.

If you have a security system or security features tied into a remote starter, you can receive warnings from the alarm portion of the system on some premium two-way remotes. If you’ve parked your car or truck at a big shopping mall, it’s not unreasonable that you’d be more than a quarter-mile away. With that said, the ¼-mile system isn’t going to work with concrete and steel walls, dozens of stores and hundreds of people on their cell phones between you and your vehicle. Transmitter power is fundamental here – both from the remote and from the transceiver in the vehicle.

A Quick Test of Remote Starter Range

To quantify some of the range claims, we headed to a local light-industrial area to test how far away we could be and still receive a reliable confirmation that a command from our remote worked. The first system featured a two-way remote control with a color display that’s marketed as offering 1 mile of range. We used the infamous remote-to-chin trick (which turns your head into an antenna) to maximize performance, and we were able to get the system to function at a distance of 2,000 feet (615 meters).

The second system features a one-button remote with LED confirmation. It’s listed as providing up to 2 miles (3.2 kilometers) of range. We managed an impressive 1.11 miles (1.78 kilometers) in our urban test scenario. Just as a note, the battery in this remote was a year old, so there is a slight chance we could have bettered that number.

Nevertheless, the real-world numbers in this test came in at 38% and 55% of the maximum the companies use in their marketing. Given the caveats of interference, these aren’t surprising. If we were in a remote part of Texas or Saskatchewan with flat terrain with no trees, cell service, radio stations or buildings, we’d have no problem believing that these systems would deliver every inch of their ratings.

We took the long-range system to a local shopping mall for a second test and parked at the very southwestern corner of the parking lot. We parked facing the door and in line with the long center hallway in the mall. This positioning would provide a best-case scenario in terms of range.

The first test was to check out the factory keyless entry system. As we walked through the parking lot, we pressed the lock button. At a distance of 195 feet (60 meters), we had to turn around and face the car for it to respond. This continued to work right up to the door of the mall at 290 feet (88 meters). The vehicle continued to react once we were through the first set of doors but not after the second. So, we’ll call that about 300 feet (100 meters) of range.

We switched to the one-button two-way LED remote that’s marketed as offering 2 miles (3.2 kilometers) of range. We continued in a straight line down the mall’s main corridor into the large department store at the end. Just as we passed the perfume section a quarter of the way through that store, we ran out of range. That’s a total of 1,400 feet (427 meters).

Given the line-of-sight benefit, we decided to stray off down a few of the side corridors. A little to the north, with a few dozen more stores in the way, the range was down to 920 feet (280 meters). Farther west of that, with even more stores between us and the car, the range was down to 740 feet (225 meters).

At no time were we disappointed with the test. It was amazing to see just how far we could get and the types of interference that reduced the effective range. On the other hand, it was no surprise to see how poorly the factory remote fob worked.

What Do You Need To Know About Remote Range?

Just as with some of the overzealous power ratings on speakers and amplifiers we see, using the longest range possible in marketing information is just a part of reality when it comes to the performance of remote starter, security and convenience systems.

When buying a remote car starter or security system for your car or truck, think about the worst-case scenario in terms of how much transmitting power you’ll need. We’ve heard of people starting their vehicles from a monorail when more than a station away from their stop or while flying into a small airport in a small commuter plane.

If you want your vehicle to be comfortable and ready to go when you are, extra power from the car starter or security system remote will give you more warm-up/cool-down time. Drop by your local specialty mobile enhancement retailer today to find out about the security and convenience solutions available for your vehicle.

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.

The Car Audio Distortion Food Chain

When it comes to expressing the quality of an audio system component, the amount of distortion it adds to a signal is the defining factor. In this article, we’ll talk about how much distortion each part of an audio system adds – so that you can target your budget for the greatest benefit. We’ll rank four categories of audio equipment based on the amount of distortion they add to your music. Ultimately, our suggestion is to optimize your upgrade budget by focusing on the products that will deliver the most significant improvement in perceived audio quality.

What Is Audio System Distortion?

Distortion is the addition of unwanted information to an audio signal. In minimal amounts, distortion can be difficult to perceive. However, above a level of about 0.5%, distortion is audible and can change the music’s tonal balance and perceived dynamics.

It’s become clear that most people think distortion is only present in an audio system when a speaker is overdriven or an amplifier starts to clip. While that level of distortion is very audible, unwanted harmonic and intermodulation distortion is added even at moderate listening levels. For example, a low-quality amplifier providing less than a watt of power to a speaker can add almost 1% distortion to the signal. A poorly designed speaker or one operating outside of its intended frequency range can easily add 3-5% distortion, and a subwoofer driven at moderate levels can be well over 10%.

No. 1 – Speakers and Subwoofers

If the paragraph above wasn’t enough of a hint, let’s make it clear: Speakers and subwoofers are notoriously non-linear. Let’s say you’re feeding a 100 Hz sine wave into an inexpensive woofer. If the design has less compliance (more stiffness) in the forward direction relative to the rearward, the driver’s output will be reduced for half of the waveform. That’s distortion. If the driver has changes in inductance relative to forward or rearward motion, there will be a reduction in output over one half of the produced audio waveform. Distortion is also possible from resonances in the cone, surround and dust cap that add significant unwanted energy.

You need to know that ALL speakers add more distortion as they are driven to higher excursion levels. Aside from not using a properly designed or constructed enclosure for your subwoofers, or trying to play the woofers in your doors at frequencies below 80 Hz, louder means less quality.

When shopping for car audio upgrades, look for speakers that include distortion-reducing technologies. We’ve talked about copper and aluminum shorting rings, copper caps and flat progressive spiders. To minimize power compression (a reduction in output as the speaker is driven at higher levels), you’ll need to choose a solution that balances cooling features like a large-diameter voice coil with acceptable high-frequency performance.

Last but certainly not least, the product specialist you’re working with needs to design, install and calibrate your audio system properly. Proper speaker mounting adapters and spacers made from weather-resistant materials are a starting point for installation. Choosing driver sizes that offer good directivity performance, so your music sounds great from both sides of the vehicle, is another important criterion. Finally, setting crossovers, equalization and signal delays to create a realistic listening experience is crucial. Getting any of these steps wrong will reduce your enjoyment of your favorite music.

Audio Distortion — The Rockford Fosgate Power Series T3652-S component set features woofers with an integrated shorting ring and a large 38 mm voice coil former for excellent power handling.

No. 2 – Amplifiers

If you’ve read our articles on distortion, then you know that we have a passion for testing amplifiers. At their worst, amplifiers add maybe 1/10th of the distortion to an audio signal that a low-quality speaker does. This doesn’t mean that they aren’t in a solid second place in terms of where you should invest in an audio upgrade.

Amplifiers are supposed to amplify a signal – nothing more, nothing less. They should output what you feed to them without adding warmth, brightness or changes to overall tonal balance.

Low-quality or poorly designed amplifiers can add distortion because of the crossover between the positive and negative output devices. In addition, they can exhibit frequency response issues from poorly designed bass boost and filter circuits. Amplifiers with high output impedance can be affected by changes in load impedance.

A second consideration for amplifiers is noise. If you turn your car stereo system on and hear a lot of hiss, it’s likely from the amplifier. Every amplifier adds a little background noise. Whether noise affects your enjoyment depends on just how much is added. The signal-to-noise ratio lets you know what’s going on behind the scenes.

A few quick tips for buying high-quality amplifiers: As far as Class-D amplifiers have come, they are best suited to powering woofers and subwoofers. The output filter networks can get a little fussy at higher frequencies. As such, Class-AB amplifiers are better for midrange and high-frequency duties. Second, the physical size of an amplifier significantly affects how much noise is added to the output. Small amplifiers are typically noisier. Third, watch how specifications on distortion are provided. The ANSI/CTA-2006-C standard requires that distortion and noise numbers be published when measured at an output level of 1 watt into a 4-ohm load. Measurements at other levels may be misleading.

No. 3 – Source Units

We’ve tested several source units lately, and though their effect on sound quality isn’t as dramatic as the speakers and amplifiers you choose, there are measurable differences from one model to another. While amplifiers have to deal with high voltages and significant current delivery, the signals inside a radio or multimedia receiver are pretty small. These low levels mean that noise from a power supply can affect what you hear.

Back in car audio’s heyday, we had CD units like the Sony Mobile ES CDX-C90, Clarion ProAudio DRZ-9255 and Alpine’s F#1 Status DVI-9990E. Of course, the days of high-end CD players are gone, but there are still a few options for a high-quality source unit.

Picking a good head unit is tough. You’ll likely choose between something mainstream with good performance or an upgrade to something designed to offer better sound quality. For example, we used to suggest 24-bit Burr-Brown D/A converters. Now, those are in almost every multimedia receiver. Our advice is to choose a product that has the features you want and is clearly designed to deliver improved audio quality.

No. 4 – Digital Signal Processors

Putting the DSP family at No. 4 in our list might puzzle anyone who understands how DSPs work and why they are an absolute necessity in a premium car audio system. Let’s make it clear that you need a DSP to equalize and filter the signals going to your speakers for them to deliver realistic performance. As such, a DSP is one of the most important components in an audio system. Its ranking in this article is based on whether or not you need to allocate extra funds to purchase a product in each category to yield better performance. So, having a DSP is a requirement; buying the fanciest one on the market won’t make a huge difference to what you hear.

Having said that, there are subtle differences, especially between entry-level and premium solutions. For example, most digital signal processors use similar DSP chips to perform the audio adjustments. As these are handled in the digital domain, the differences in transparency are more about the analog circuitry and the conversion process.

One tip: Don’t let yourself be fooled by claims about support for high-resolution in a DSP. In most cases, the analog-to-digital and digital-to-analog converters are noisier when running at higher frequencies. Stick with solid performance and ensure that you have an expert configure the system, and you’ll be delighted.

Choose Your Car Audio Upgrades Wisely

Here’s one last thought on buying high-quality car audio equipment: Every brand on the market is competing for your dollar. Some of them offer excellent products that result from hours, if not years, of designing and testing to deliver the best possible performance. On the other hand, some products are just expensive while delivering mediocre performance. So make sure you take the time to audition several options from different specialty mobile enhancement retailers near you.

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.

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