Car Audio in the 21st Century

Car Audio in the 21st Century

Stereophonic sound reproduction dates back to the 1930s when it was developed by Bell Telephone and a British sound engineer named A.D. Blumlien. But it wasn't until the 1950s that affordable stereo technology began making its way into our homes. A fusing of two Greek words meaning "solid" and "sound," the term "stereo" generally refers to a type of sound reproduction using two separate channels regardless of how many speakers there are.

Of course, the modern "stereo" or audio system has moved well beyond a simple turntable and two speakers. Today's audio systems are highly complex and can often reproduce music that sounds even better than the original thanks to multitrack recording and sophisticated mixing equipment and techniques. With the advent of digital technology and the ever shrinking size of the needed components, many of us are able to purchase home audio equipment that as recently as the 1980s would have been considered professional-grade.

As home audio has changed, naturally, so has car audio. One of the areas in which we've seen the biggest improvement is in the level of sophistication of entertainment systems we find in today's cars — specifically, sound reproduction and clarity.

Home Audio Meets Car Audio

It wasn't too long ago that the average car was lucky to have a radio in the dash and two small speakers in the front doors — more expensive cars would upgrade you to a four-speaker system by adding two 6-by-9s in the rear package tray. Now, the systems in some cars are becoming as good as a basic home audio system. This is all the more impressive when you take into account the obstacles involved in designing a car audio system. Consider the environment: there's vibration, heat and wind and road noise. Consider the acoustic environment: there's glass, leather, plastic trim, etc., each material presenting a different acoustic property to the speakers — glass being highly reflective, leather less so, and so on. Taken together, these factors present a formidable task to car audio designers.

As automakers struggled to improve sound quality, they began looking to home audio for solutions. Home audio manufacturers like Pioneer have been offering car stereos for decades, but only recently has there been a huge influx of home audio names into the passenger car arena. Currently, there are two major suppliers of high-quality car audio systems: Bose Corporation and Harman International. When you hear a good factory sound system, chances are you'll look up and see the Bose or Harman logo. Bose markets under the Bose name only; Harman markets under the JBL, Infinity, Harman-Kardon and Mark Levinson names.

Dolby, Surround Sound and DSP

Dolby Pro-Logic comes out of the home entertainment world, where it is used to manipulate the audio signal for maximum effect. So far, we have only seen this technology in Volvo vehicles, but the results are so impressive that it bears mentioning. The Volvo Dolby Pro-Logic factory sound system is among the handful of systems that we've rated a 9 out of 10. It truly must be heard to be believed. Whether other automakers will follow suit remains to be seen, but Volvo deserves recognition.

Surround sound is another technology coming from the home audio/video arena. The idea here is to wrap the listener in an envelope of sound. In other words, we've moved way beyond right and left speakers and plain old stereo. Now the sound comes at you from right, left, center and behind. A system that does this most impressively is the Mark Levinson system found in the 2003 Lexus LS 430. The listener literally feels like a part of the music, no matter where he or she sits. Gone is the boxy sound of right and left stereo speakers; instead, the listener is transported to a higher plane of listening, where every sound is detailed and lush. It's truly a memorable event, and this system has become the benchmark against which we measure all other systems. If you read on to our "Beyond CDs" section, you'll see that systems like the Mark Levinson aren't considered "surround sound" under the strictest definition of the term. We say this not as a criticism of the Mark Levinson but instead as a reminder that even greater sophistication is on the way.

DSP (Digital Signal Processing) is one more bit of technology making itself heard in current models. Appearing first in car audio about 10 years ago, DSP has gone through some changes and now finds itself in factory sound systems. For a listen, get hold of a 2003 Ford Explorer or Expedition equipped with the premium sound system. DSP works by manipulating and delaying the audio signal to create a psycho-acoustic effect (yes, that's a real word) and "fool" the listener into hearing something that isn't there. In layman's terms, the delay creates a series of echoes that have been preprogrammed to give a certain effect. In most systems, there are several settings, such as "Concert Hall," "Jazz Club" or "Stadium."


MP3 technology pertains to music files compressed and saved in a digital format. MP3 files have typically been transmitted over the Internet and saved on compact discs. Although companies such as Napster have gone by the wayside (Kazaa is still going strong, with 270 million downloads, but for how long?), MP3 remains a popular format, particularly among younger listeners. Its main drawback, other than well-publicized clashes with the major record labels, is that its sound quality suffers due to the compression needed to fit so many tracks or files onto one media source. Andrew Cznik of the Art Institute's Center for Digital Imaging and Sound observes, "MP3's compression algorithms severely compromise sound quality. On high-fidelity systems, the difference between MP3 and even CDs (not to mention DVD-A) are quite noticeable even to the untrained ear."

But, the advantage of the MP3 format is that it allows virtually hundreds, if not thousands, of files to be saved and manipulated at the user's discretion without taking up much space. Several aftermarket radio manufacturers, such as Kenwood and Alpine, have released MP3-capable head units, and many of today's automakers are offering factory-installed audio systems that are capable of playing MP3-encoded CDs. 2003 and 2004 Model Year vehicles such as the Pontiac Grand Am, Ford Ranger Edge, Honda Element EX, Ford Focus SE, Mazdaspeed Protege, Pontiac Grand Am GT1 and the Bentley Continental R offer MP3 players as standard equipment. Other vehicles like the Mazda MPV LS, Chevrolet Cavalier LS, Hyundai Elantra GLS, Ford Mustang and Pontiac Montana offer MP3 capability as an option.

Despite its limitations, there are those who feel MP3 technology is still worth considering. Dan Benyamin, chief technology officer of PhatNoise, a company that manufactures a leading-edge car audio MP3 system, says, "The reason MP3s became so popular is, you can compress a lot of data — roughly 10 times what a CD can hold." Instead of using compact discs to store the data, PhatNoise has manufactured what is essentially a miniature computer that goes in the trunk of the car. The musical data is transferred from the home computer to the car computer via a portable hard drive attached to a USB port. Benyamin said the company's standard system holds 5,000 to 6,000 tracks, all categorized and announced via a voice prompt. The PhatNoise system is customized for different vehicles, and presently the company has 15 flavors — and growing — for various auto manufacturers. We were impressed with the PhatNoise system, and believe the company is well positioned should the technology really take off. For more information, log on to

Only time will tell if MP3 is simply a transitional technology (like Beta videotapes and Minidiscs) or if it is here to stay.

Beyond CDs

Two new technologies that are already changing the way we listen to music are Super Audio CDs (SACD) and DVD Audio discs (DVD-A). SACD and DVD-A both offer the added benefit of reproducing music in true Surround Sound 5.1 whereas a normal CD is capable only of stereo playback. Although many car systems offer a "surround sound experience" that effect is often achieved electronically and has little or nothing to do with the original recording. As a side note, the "5.1" designation refers to the number of monitors (speakers) a system uses. Audio engineer Chris Rolfe explained, "The '.1' in 5.1, 6.1, 7.1 (and, yes, even 10.2) systems refers to the Low Frequency Effect channel, that is, the subwoofer…." The first number is the number of normal speakers. So an in-car system that offers Surround Sound 5.1 offers five speakers with one subwoofer.

SACD was developed by Sony and uses a more sophisticated recording method, but has yet to find its way into the in-car audio world.

Regarding DVD-A technology, Cznik says, "DVD Audio is meant to be a higher-resolution 'successor' to the CD." DVD-A improves sound quality by offering higher resolution, which is achieved by using a higher sample rate. What this means to the average consumer is that DVD-A offers a fuller and more accurate sound experience over normal CDs — music with as much as 500 times higher resolution over a CD but in the same compact size medium. We've experienced a DVD-A system for ourselves, and the sound quality is excellent — a true rival to the stellar Mark Levinson systems we've raved about in the past.

Acura is leading the charge for DVD-A in-car systems. The 2004 Acura TL offers a DVD-A system that will also play normal CDs. In addition, the Acura system allows for more flexible control of the sound by offering more separate level controls than most other systems currently on the market. Although Acura is the first to offer this in-car technology, we wouldn't be surprised to see it in other vehicles in the near future.

The only real drawback to DVD-A is the small number of available titles. The list is growing, and clearly, many top sellers of the past will be released on DVD-A, but what is the chance you or I will be able to replace our entire CD collection with DVD-A? Czink advises, "Just like with the advent of CDs, I think we'll see lots of activity from the major labels rereleasing their old catalog material while they feel out the market. Old material doesn't cost as much to produce…I think that the majority of stuff that's currently on CD will probably not make it onto a higher-resolution format unless it's a proven seller." So look for Pink Floyd's Dark Side of the Moon to make it to DVD-A but perhaps not the collected works of Culture Club.


Radio Data System (RDS) is a feature found in many new cars, and it has more to do with the radio portion of an in-car audio system. It is able to read a digitally encoded signal sent from various radio stations (not all stations in all cities offer the service) that can provide additional information through your car stereo's head unit. If you own a car where the radio shows the station name and/or song and artist title on a small screen, then you probably have RDS in your car. Other features include the ability to find radio stations by program type, along with traffic and weather monitors. Say you're away from home and nothing would make your day quite like a good country-and-western ballad. Simply choose "country" as a PTY (program type) and the radio automatically runs through the dial looking for country radio stations based on that code they're broadcasting. Also, you can select a button labeled "TA" or "TRAF" and the radio will automatically switch you to another station when a traffic report begins. In other cars, you may find a button with a WB (weather band) label that when pressed will take you to a current weather report.

Satellite Radio

Last, but certainly not least, is the introduction of one of the most exciting innovations to take place in car audio since the invention of FM radio. This is a technology whose time has come, and it is poised to change the way we listen to music in our cars. Known as satellite radio, the technology is exactly what the name implies: radio signals coming to your vehicle via satellites above the earth. Think of it as the audio version of DirectTV or Dish Network, and this will perhaps give you a better idea of what we're talking about.

Of course, Rome wasn't built in a day, and neither was satellite radio. Using the analogy of satellite TV once more, think of your satellite dish as traveling down the highway at 70 miles an hour, and this might give you a glimpse of the technical problems that needed to be addressed in bringing this technology to market. After nearly 10 years of development and delays, we're happy to report that most of the technical challenges have been solved, and satellite radio can now be beamed into the passenger compartment of your car, truck or SUV.

At this point, there are two main competitors offering satellite radio to the masses: XM Radio and Sirius Radio. We spoke to both companies for this story, and both have much to offer the consumer. Here's the skinny: XM Radio came out of the box faster and has seen phenomenal growth in the past year; Sirius Radio, while slower in its growth, comes to market with its own advantages and is worth consideration.

According to Chance Patterson, VP of corporate affairs for XM Radio, "Sirius is a year and a half behind us in technology. This is because they used outside vendors to develop their chipset, while we did ours in-house." Sirius Radio contends, however, that its Lucent-designed chipset was worth the wait. Todd Goodnight, director of product management for Sirius, notes, "Technical barriers caused us tardiness, but this is a very robust chipset, the first of its kind."

The two vendors also differ in the approach to launching their satellites. Sirius has three satellites in its air, traveling above the earth in what is known as a geo-synchronous orbit. According to Goodnight, this orbit is advantageous, as it brings the "birds" over more of the continental United States, providing better coverage and reception. XM, on the other hand, flies its two satellites in a geo-stationary orbit. As a result of this difference, claims Sirius' Goodnight, XM Radio utilizes up to a thousand land-based repeaters to broadcast its signal across the country, while Sirius uses as few as 100.

What other differences exist between the two systems? Well, price, for one. The XM Radio monthly subscription will set you back $9.95, while Sirius runs $12.95 a month. But if you hate commercials, you might consider paying an extra $3 a month. Said Sirius' Goodnight, "All of our music channels are commercial-free. That's 60 channels of commercial-free music. XM only has 35 commercial-free channels."

Both systems offer adapters and units that attach the satellite radio to existing car audio systems or home electronics, so you can have your music either on the go or on the sofa. XM has partnered with Delphi to bring to market Delphi's sleek XM SkyFi Radio. For around $200, plus roughly $70 for an adapter, this setup can be adapted to any car radio. However, one of the coolest aspects of the SkyFi Radio is its ability, with a $99 adapter, to morph into a portable boom box for the home. Not to be outdone, Sirius has a new plug-n-play unit for $99 that adapts with a $70 cradle. The company has also signed a deal with Kenwood to produce a high-end line of home components that will be Sirius-capable.

Of course, more and more cars are coming with satellite radio-ready systems from the factory. XM has aligned itself with the GM family of vehicles, plus Acura/Honda, Audi/VW, Nissan/Infiniti and others. XM radio is currently available in such 2004 model year vehicles as the Chevrolet Impala, Cadillac Escalade, Audi A4, Honda Accord, Nissan Maxima and the newly redesigned Toyota Camry Solara. XM radio is also available in select Avis rental cars. Sirius has signed deals with Ford, BMW, Chrysler and Nissan/Infiniti products and is available in vehicles like the Chrysler Sebring, Dodge Grand Caravan, Ford Mustang, Jaguar S-Type, Mazda Tribute, Infiniti G35 and select Hertz rental cars. Almost all Audi, Nissan and Infiniti vehicles have the option of using XM or Sirius Satellite Radio. Aftermarket manufacturers such as Audiovox and Kenwood are also offering satellite-ready units. All you need to do to activate either setup is to sign on the dotted line, and up to a hundred channels of music, talk and sports will beam into your vehicle.

In Conclusion

Certainly we've come a long way since the early stereophonic recordings of the 1930s. As home audio systems have improved so have in-car systems — in fact, it's the automakers' decision to utilize such home audio giants as Bose and Harmon-Kardon that makes today's car stereo so much better than they were only 10 or 15 years ago. While the future of new processes and storage formats such as MP3 and DVD-A seem unclear, we can be sure that the automakers will continue to improve on their successes and bring more and more refinement to the one thing there is no substitute for — a loud stereo in a fast car.

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