When it comes to listening to music, there seem to be two kinds of listeners in the context of “where the sound comes from.” Some people want to be enveloped by the music. They want to feel like they are in the very middle of the performance, with sound all around them. This style is sort of like listening to a set of headphones. The other listener wants their music to come from in front of them. This “forward-facing soundstage” style is more like listening to a home audio system or a movie theater.

There is no right or wrong – everyone has their preference. But high-end mobile audio systems are, for the most part, designed for the latter – people who want to feel as if they are sitting in the middle of the audience at an amazing concert.

There is also that guy in the Monte Carlo with the 6x9s in open-backed boxes in the rear window. He, thankfully, is gone now. If you happen to see him, cut off his mullet and drag him to a car stereo shop, please, and thanks!

Imagining a Soundstage

This article talks about an imaginary soundstage. But what in the world is a soundstage?

Imagine a band set up on a stage 20 feet in front of you. Let’s say there is a lead singer in the center of the stage, right at the forward edge. Behind him or her, someone is at a grand piano. To the right of the piano is a big drum kit with several cymbals all around the performer. In front of the drummer, to the right of the lead singer, is someone sitting on a stool with an upright bass. To the left of the singer is someone with a trombone. To the left of them is someone with a trumpet. Behind the trumpet player, to the left of the pianist, is a xylophone player. The xylophone player is also going to sing some backing vocals. So is the drummer.

Imagine those different positions for a second. They not only range laterally across the soundstage, but there is depth to their locations.

This unique and perhaps rare grouping of performers represents all the source aspects of your soundstage, but their locations don’t represent the limits of that stage. Let’s consider the venue in our analogy as well. A medium-size club of some sort. Wooden walls, a hard floor and a high ceiling. The room where we listen to our performance is a huge contributing factor to the sound of the performers. (If you ever have the chance to visit the Ryman Auditorium in Nashville, TN, do it! Even if you aren’t into country music, this venue is amazing.)

So, here we have our performers and our venue. We are going sit about 20 feet back from the center of the stage and let the show unfold for us. Our experience as the performers play defines the soundstage. We hear each instrument in its position on the soundstage. We also hear the sound of those instruments reflecting off the side walls of the club.

To reproduce the performance accurately, we need to reproduce those reflections as well. Capturing those reflections requires a specific recording style – so it may, or may not, happen. A recording of a live performance is much more likely to have that information than a studio recording.

Our Auditorium on the Road

There it is. The space in front of us, where the music is coming from, is our soundstage. If you get a chance to listen to your favorite recordings on a high-end home audio system, and you choose to sit equidistant from the speakers, then you probably have experienced a fairly accurate soundstage. The perceived location of where our music is coming from regarding height, width and depth is our soundstage.

Sadly, most mobile audio systems can’t or don’t recreate this very well. It’s a shame, because experiencing each performer in their correct location, including depth (one performer behind another) brings an amazing level of realism to your music. The good news: Recreating a soundstage in your car isn’t all that hard.

If you let the salesperson and installer at your local mobile electronics retailer know that you want a soundstage in your vehicle, they can design your system that way. Let’s assume we are building a whole new system from scratch, just to make this easier.

The first step will be to select a set of good-quality speakers for the front of your car. You mostly likely will want a component set unless you can fit a large (5-1/4” or larger) coaxial on the dash. Since most vehicles have the front speakers down low in the door, using a component set will let the shop you use install the tweeters up high and far forward. If the tweeters play low enough, say 2.5 kHz, then a skilled tuner can make the sound appear to come from the dash level, rather than the floor.

The next step to creating a soundstage is to have a way to tune those speakers. We aren’t talking about amplifier gain settings. We need control over equalization, output level and signal delay. Because the driver of the vehicle sits closer to the left speakers, those will appear to be louder, and we will hear the sound being reproduced by them sooner than the sound from the other side of the car. The simplest of systems with great soundstages will have either a source unit or external DSP unit with three-way crossovers, stereo equalizers and the ability to delay the signal going to each speaker.

With the above tools in place, your installer can set up the system so the sound coming from each speaker in the front of the car – from both midrange drivers and both tweeters – arrives at the listening position at the same time. Your installer will also tune the system so the left side of the car sounds the same as the right side. This tuning helps to eliminate frequency steering. Frequency steering causes the source location of a sound to move around the soundstage depending on frequency.

Next-level Performance

The above example offers a great two-way front stage. We would, of course, assume you are going to use a subwoofer in the system. A set of door speakers, even great ones, won’t be able to reproduce the bottom octave of the audio spectrum with any authority. With the sub in the system, it’s now called a three-way system. What if you want the system to sound even more realistic in terms of the placement of voices on the soundstage?

One way to improve your soundstage is to install a set of midrange drivers up high and far forward in the car. The A-pillars, dash speaker locations, and high and forward in the door are common midrange locations. If you can get a midrange that will play down to at least 300 Hz, the ability to solidify the dash as the source of the sound becomes much better. Rather than having deeper voices coming from lower in the door, now they will be focus better across the dash.

Another advantage of a three-way speaker set is that the woofer is often capable of producing slightly deeper midbass than an equivalent two-way speaker set.

The four-way system is going to cost more. You need two more speakers, two more amplifier channels, somewhere to mount those new speakers and probably another 30 to 60 minutes worth of system tuning. But yes, it’s totally worth it.

In these systems, the focus of performance is tailored to the driver’s seat alone. The passenger isn’t going to enjoy the same experience. That said, if you and your co-pilot both want to enjoy equally amazing audio, there are solutions in the works. By the spring or summer of 2017, everyone in the car will be able to enjoy an amazingly realistic soundstage across the dash.

This article provides an overview of the system design requirements for creating a system with a good soundstage. There are a lot of variables and hundreds, if not thousands, of options regarding how to execute to fine-tune the concept.

This is where your experienced mobile electronics retailer comes in. Use their knowledge, skill and experience to help bring your desire for musical realism to reality. If you’re out cruising around, drop into your local mobile electronics specialist retailer and ask if they have a demo vehicle that produces a great soundstage. If you have never experienced one, you will be blown away! Best Car Audio will not be held responsible for the ensuing audio addiction.

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.

If you have been around the mobile electronics industry for more than a decade, then you may have noticed some significant changes. New technologies make our time behind the wheel safer, more entertaining and more productive. Many products offer better performance and efficiency compared to their originals. Innovations and technological advancements let us do things that simply were not feasible decades ago. This article looks at some of the most significant changes that have taken place in the car audio industry over the past few decades.

The Mighty Head Unit

Let’s see how far you want to go back. Mono FM radio? The 8-track? Perhaps a turntable under the dash of your 1960 Chrysler? Things have come a long way in source units and their features. We saw cassette players, the mini-disc (if only for a year) and even CD players come and go. We introduced digital media with MP3 files, then added WMA, WAV and – most recently – FLAC file playback. Soon, Master Quality Authenticated (MQA) will join the ranks.

The introduction and popularity of the Apple iPod signaled a massive change in the philosophy of music lovers. While this handy device could be considered the “nail in the coffin” for the record store industry, it launched new levels of convenience for music accessibility. The mobile electronics industry embraced the iPod, and now, support for it is standard on all mid- to high-level source units. Similar support for Android-based smartphones has also become almost a standard feature in the last few years.

Miniaturization and the advancement of computer processing have given us full-color touchscreen interfaces with fancy animated graphics. We can watch a DVD or digital media movie while having lunch in the car. Portable navigation systems have replaced paper maps to help us travel safely and more efficiently.

Recently, we have introduced connected technology solutions. Internet connectivity is a feature in many new car radios, most often via your personal smartphone. Access to the Internet allows you to stream music from online resources like Google Play or iTunes Radio. Apple and Android have developed interfaces for their smartphones to enable drivers to send and receive text messages, make phone calls, select navigation destinations, and choose the music they want to listen to by just talking to the radio. CarPlay and Android Auto are the current “big thing” in multimedia source units.

Those Oh-so-fun Subwoofers!

What could you change when it comes to the design of a speaker? Materials for cones, suspensions, surrounds and motors haven’t advanced all that much, and because a subwoofer reproduces only low frequencies, things like cone materials don’t have a dramatic effect on performance. What has changed is our ability to model the behavior of the magnetic field within the speaker. Being able to optimize the geometry of the magnetic field allows designers to create subwoofers that are more efficient and that offer better performance with less distortion at high excursion levels.

The size and location of the subwoofer enclosures we use in our vehicles have become and more important. Back in the “good old days,” if you wanted big bass, you had to give up your trunk. Now, many subwoofers are designed to play nice and low in a very small and shallow enclosure. Using these subwoofers allows your installer to create compact solutions that will fit in a spare-tire well, the corner of your trunk or even in the footwell of some vehicles. We should be clear; there is a trade-off with these subs – they often require more power to produce the same output as a “conventional” subwoofer, but power is inexpensive these days.

Amplifiers, Smaller, More Power

Power is cheap. You can buy a great-quality 1,000 watt subwoofer amplifier for around $500. Decades ago, a 1,000 watt amp was among the biggest amps available, and it cost several thousand dollars. That amp was also the size of a skateboard and consumed a lot of power. Modern amplifiers are much smaller and much more efficient, sound better and consume less power. A lot of people credit the increase in efficiency to Class D designs. While switching to Class D for many applications makes sense, there have been efficiency improvements thanks to being able to use small microcontrollers and high-tolerance components in a Class AB amp.

In the past few years, more and more companies have been offering amplifiers with built-in advanced signal processing. On the most basic of amplifiers, we have crossovers and bass boost circuits. More advanced amplifiers offer both high- and low-pass filters on the same channel for midbass and midrange applications. Some amplifiers even provide low-frequency signal restoration processing. A whole other class of amplifiers on the market has built-in DSP processing. Some are so advanced that they don’t have a single analog adjustment on them.

Signal Processing Moves To Digital

Years ago, signal processing meant you had an EQ and a crossover in your car. These in-dash processors were made popular by the 1/2-DIN equalizer – a 1×7-inch EQ that would mount in the dash above or below your radio. These little EQs offered as many as 11 bands of graphic equalization to let you “tune” your system. Some had subwoofer level controls and crossovers built in.

The next step in processing was the stand-alone processor – usually either an equalizer or a crossover, sometimes both. These were the size of a medium-sized hardcover book and gave installers much more precise control over system tuning. The drawback was their physical size. They took up a lot of room.

Almost all of these are gone now, replaced by stand-alone DSP processors. These seemingly magic black boxes replace those old stand-alone equalizers and crossovers, and include options like signal delay and the ability to switch between different settings at the flick of a switch.

Modern signal processing has allowed installers to use signal delays to optimize seemingly unconventional mounting locations for speakers to produce an amazingly accurate soundstage.

Speaker Placement Becomes Less Critical

In the past, if you wanted a great soundstage in your car, then you had to work with placement to equalize the difference in path lengths between the front speakers. Autosound competitors would go to great lengths to move seats as far back into the vehicle as possible, and some even built vehicles with a single seat located in the center. It was all somewhat silly because that effort never translated into value or performance for the consumer. All consumers could get were kick-panel–mounted speakers or a compression horn under the dash to aid in equalizing distances.

With the assistance of modern signal processing, installers can use factory locations, then delay the signal going to the closest speakers to put you in the center of them.

Another speaker location that has become popular is the A-pillar speaker pod. A nice midrange and tweeter up high and far forward in the vehicle can help create a deep and wide soundstage. The drawback with this approach is that it only works for one seat. If it is set up for the driver’s seat, the soundstage for the passenger seat is compressed into the right-side speaker location.

Very soon, the newest of processors will offer provisions to make every seat in the car sound great using an up-mixer and a center channel, just like the one in your home theater. Now, both front seats and even passengers in the rear can experience an even and focused soundstage across the dash of the vehicle.

Modern Speakers Refined

Like subwoofers, speakers haven’t changed dramatically since the first fixed-magnet, moving-coil speaker was created in 1925. Speakers have improved in efficiency and accuracy thanks to better materials for surrounds, better adhesives and dramatically better processes that help speaker manufacturers build more-consistent products. The real performance upgrades have come in the optimization of a speaker’s motor assembly with respect to the interaction between the voice coil and the magnetic field.

As a speaker cone moves in and out, the magnetic field strength varies. This causes distortion. The same goes for the suspension system: Being able to model the behavior of different surrounds and spiders allows designers to produce transducers that are more linear and, thus, create less distortion.

The Incredible Car Audio Evolution

Overall, the latest innovations and technologies have moved the mobile electronics industry to a point where the modern in-vehicle infotainment system performs at a level that could not be conceived of even a decade ago. If you want to find out about the latest technologies or products, drop into your local mobile electronics specialist. They would be happy to show you the latest and greatest offerings 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.

To optimize the performance capabilities of a speaker, it should operate within the frequency range for which it was designed. A woofer or subwoofer won’t be able to reproduce high frequencies accurately. A tweeter will self-destruct if you ask it to try to play bass frequencies. For this reason, we use three- and four-way speaker systems in most vehicles. That means using crossover networks.

The purpose of a crossover is to split up the frequencies that pass through it. We are going to delve waist-deep into the benefits and drawbacks of the crossovers commonly used in car audio system component speaker sets.

How a Passive Crossover Network Works

A passive crossover network is a component or group of components that is installed on the speaker wires between an amplifier and a speaker. The behavior of these components attenuates portions of the signal going to the speaker itself. Four components are commonly used in passive networks: capacitors, inductors, resistors and protection devices.

The combination and configuration of these components are used to create a low-pass, high-pass or band-pass filter network. Resistors are used to attenuate the output of devices, or sometimes used as part of a frequency-dependent impedance correction circuit called a Zobel network. Some manufacturers include light bulbs, diodes or some form of positive temperature resistors to limit how much voltage a tweeter receives. Completely passive active networks have been available (but that was a long time ago).

How an Active Crossover Functions

An active crossover is a device that modifies an audio signal before the amplifier. It works on line-level or preamp signals only. Active crossovers combine op-amps, resistors and capacitors to alter different frequency ranges of the signal. Unlike passive networks, active crossovers can be designed to increase the level of the signal, but only in the case of powered filters. Active networks are often include other functions, such as remote level controls and bass boost circuits.

Benefits of Passive Crossovers

It is worth noting that each passive network is designed to work at a specific frequency for a specific speaker. If you change the speaker, the filter will not respond in the same way. In some cases, if the impedance of the speaker is significantly different from the one the network was designed for, the speaker may be damaged, or portions of the network may become damaged.

Passive networks are easy to use. You run a wire from your amplifier to the input of the network, then connect each speaker to the output. Other than mounting the network in a dry location that is free from vibration, that’s about all you have to consider.

Some passive networks include some form of output level attenuation. Most use a two- or three-position switch. Some use jumpers. An extremely high-end network may include a variable L-pad or potentiometer for extreme fine-tuning capabilities.

Passive crossovers allow you to split the power of a single amplifier channel to drive two different speakers. Fewer amplifier channels can dramatically reduce the system cost, since you only need a pair of amplifier channels to run a full set of speakers.

Limitations of Passive Crossovers

Since a passive crossover network is designed for a specific frequency, once the parts are chosen and assembled, there is no way to change that frequency without introducing new or additional parts.

Designing a passive crossover can be somewhat complex. The simplest of networks rely on some basic assumptions about the impedance of each speaker at the crossover frequency. Designing a network that compensates for the complex reactive load that speakers create as they move is difficult. It requires computerized modeling software and a way to measure the impedance and frequency response of the speaker at varying drive levels.

High-quality passive crossovers are designed for a specific distance and angle between the woofer and the tweeter. If the network is designed for the speakers to be far apart, moving the speakers close together will cause the signals to sum incorrectly. Even changing the angle of a speaker can have a dramatic effect on the frequency response at the crossover point.

Passive crossover networks have limitations in how much power they can handle. The magnetic fields created in an inductor have a limit. The voltage applied to a capacitor also has a limit. Crossover networks can and do overheat and fail if too much power is sent to them.

Passive crossover networks consume energy. Using a speaker system with a passive network is not quite as efficient as one using an active filter network. The overall efficiency of the crossover network depends on its complexity and the quality of the components used in the network.

Passive crossover networks are somewhat susceptible to noise. If you run a wire with an AC signal on it past the inductor in a passive network, the network can easily pick up that signal and add it to the audio signal. Choosing a safe location to mount passive crossover networks is important.

Benefits of Active Crossovers

Most active crossover networks are adjustable. That means by turning a knob or moving a switch, you can change the crossover frequency. This flexibility makes active crossovers suitable for use with almost any speaker system. Most active crossovers also include level controls, so you can easily fine-tune the level of the midrange and tweeter to compensate for different mounting locations.

Active crossovers don’t care how powerful your amplifiers are because they process the signal before it enters the amplifier. Active crossovers are also not very sensitive to temperature variations, so they can be very accurate, all the time. If one of the amplifiers channels in an active crossover system clips, the distortion only affects that single channel.

Challenges of Active Crossovers

Because active crossovers are universal in design, being able to set crossover frequencies accurately can be challenging. Labels on potentiometers are notoriously inaccurate. Most active crossovers have fixed attenuation slopes. You can’t change these slopes to compensate for response characteristics or placement variations. Unless the speaker manufacturer provides it, or you have extensive experience in measuring the electro-mechanical and acoustic response of the set of speakers, knowing what frequency to cross speakers over at can be difficult. Too low and you risk damage to the tweeter. Too high and you get distortion from the midrange. Many speaker combinations also require the over- or under-lap of the crossover frequencies to produce a flat response.

An active crossover requires a dedicated amplifier channel for each speaker. These extra channel requirements can increase the cost of designing a system.

The Perfect Solution

If there is no limit to your budget, the ideal crossover solution for a set of speakers is an active crossover with a Digital Sound Processor performing the filtering. A DSP will offer adjustable crossover frequencies, and most offer adjustable crossover slopes and alignments.

No matter what you choose, it’s a good idea to spend some time with a high-resolution RTA to make sure your system is set up for the smoothest, flattest response possible at the crossover frequency.

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.