By Jil McIntosh

Volvo Dolby Pro Logic II 5.1 Surround Sound system
Volvo S60. Click image to enlarge

Being of a certain age, I remember when a high-end car radio was one that came with an FM band, and if you went all the way to the top – or if you bought an aftermarket system – you could play your own choice of music through your eight-track tape player.

That was then, and this is now. Today’s consumers, familiar with the huge strides made in playback quality and accustomed to “surround sound” in both public and home theatres, are demanding the same type of sound reproduction in their automobiles. To that end, Volvo Canada recently invited members of the press to its Audio Symposium, to illustrate its Dolby Pro Logic II 5.1 Surround Sound system. Although the system isn’t new – it was introduced on the Volvo XC90 in 2001 – for 2005 it becomes available on every Volvo model, either as standard or optional equipment.

“Surround sound started with Star Wars,” says Martin Lindsay, Dolby’s director of licensing business development for automotive entertainment. “Dolby started in cars with the cassette, but now multi-channel technology is not restricted to the home, and customers have higher expectations. They’re spending more time in cars and it is improved entertainment.”

Volvo currently offers three stereo systems: a base system, a mid-level that is similar but with more speakers, and the top-of-the-line Pro Logic II. While the top-line system itself is not exclusive to Volvo – it’s currently used in a few other high-level brands, including Jaguar and Aston Martin – its set-up and placement within the vehicle is. Unlike many manufacturers that simply add a company’s stereo and speakers to their cars, Volvo designs and tunes the system itself to each particular model. Once the configuration is decided, the components are subcontracted to the companies, such as Sony or Fosgate, that are capable of producing exactly what Volvo needs. Dolby, a multi-level supplier, does much of its business in the integrated circuits that are used as decoders to turn stored electronic code into sound.

Volvo Dolby Pro Logic II 5.1 Surround Sound system
Volvo S/V 40. Click image to enlarge

Cars present unique challenges and advantages when it comes to installing stereos. On the down side, the engineer is dealing with a very small space, which makes bass reproduction especially difficult; the speaker locations are dictated by where they’ll fit in the doors or dash; the soft upholstered areas and the hard windows create dead space or “early reflection” of sound; and the stereo has to compete with noise from the engine, tires or wind. On the plus side, the engineer knows exactly where the listeners will be sitting, and precisely what the “room” looks like, as opposed to designing a home theatre that will be set up differently in each household.

The point behind surround sound is to produce a listening environment that mimics reality. To illustrate, imagine sitting in a concert hall, listening to a live band on stage. Most of the sound will come from the stage, but because sound is reflected off the wall behind you, you will also hear sound coming from behind and beside you. This balance of sound is all but impossible to create with a traditional four-speaker car stereo, even when the fade and balance buttons are tweaked.

Volvo Dolby Pro Logic II 5.1 Surround Sound system
Volvo XC90. Click image to enlarge

The most important component of the Pro Logic II is a centre speaker, mounted in the dashboard, along with the system’s ability to take the two channels from the recorded music and “divide” it into five, to be proportioned to each speaker. The system places most of the vocalist’s input into the centre speaker, with a portion of it placed into the two front speakers. This creates what engineers call a “stereo triangle”, which results in a central “sound image” or “sweet spot” that is missing in regular stereo systems. The rear speakers produce an approximation of the reflected sound that you would hear coming from behind you in a live performance. Because the centre speaker carries back to the rear passengers, everyone in the car has the impression of musicians playing in front, with reflected sound all around them as in a concert hall. Although it’s possible to manually adjust the speaker balance on the Pro Logic II system, it isn’t necessary; the system is pre-tuned to the vehicle and to the driver and passengers, and requires no further adjustment.

Volvo Dolby Pro Logic II 5.1 Surround Sound system
Volvo S60. Click image to enlarge

None of this comes easy; Hans Lahti, technical specialist of audio at Volvo Car Corporation, says that sixty people work on the company’s audio team, overseeing audio, navigation, telephone and entertainment systems. The team follows the car through the entire four- to five-year cycle required to take each vehicle from the designer’s pen to the dealer’s showroom. That five-year timeline hits the audio team especially hard. “The difficulty is that electronics go through their product cycles much faster,” Lahti says. “It’s not an easy task to stay ahead.” But it’s worth it; Lahti mentions J.D. Power and independent Swedish studies that show buyers rate the importance of the stereo system at number five out of 42 auto features; 79 per cent of consumers find sound quality very important; and 50 per cent get their strongest musical experience in their cars.

Each model receives its own tailored system; surprisingly, given their size, SUVs are the most difficult, because of speaker placement and bass reverberation. Although all are Pro Logic II, there are differences between the upscale systems depending on the model, with each receiving the number and type of speakers it requires for the best listening experience.

The system uses MOST, the name for an architecture consisting of modular components; this isn’t the single unit that you’re used to seeing someone stick into a dash. “The visible part is just a control panel,” Lahti says. “It is not a head anymore.” Instead, the individual components – including the CD player, receiver, speakers and antennae – are self-contained in “black boxes” that are joined digitally, rather than by wires. “The MOST system is very difficult to modify with aftermarket components because it’s modular,” Lahti says. “But most Volvo buyers don’t go to aftermarket. They want to buy it and be done with it.”

Speaker placement proves the most difficult task for audio engineering. “The tweeters are high in the doors, and the left-hand tweeter is aimed at the right-hand passenger and vice versa,” Lahti says. “This is called ‘toe-in’. Then there’s a mid-range speaker in the middle of the door, and woofers in the bottom of the door. This is the only system with three-range in the door.

“The woofers are difficult because they are big and heavy,” he adds. “The woofer has to have a box, so the door acts as a speaker box. It must be heavy and well-sealed, so the whole door works as a speaker.”

The subwoofer, Lahti says, is the most misunderstood component in an audio system. “People buy subwoofers that aren’t really subwoofers. They’re just woofers that don’t reproduce really low bass, under sixty megahertz. Many people think they’re hearing low bass, but they’re really hearing mid-range bass. Putting it all together is difficult. The subwoofer can be added as an option (to the Pro Logic II), and picky audiophiles would want it, but most people are happy with mid-range bass speakers, which also include the low end of male voices.”

So how does all this translate? Volvo had its cars available at the event, where we were invited to take them for a “test listen”.

The Pro Logic II has an override button that turns off the surround sound, and it isn’t until you push it that you realize just what a difference it makes. Without it, the system is typical of most audio systems. The playback is very good, clear and crisp. But even after some fiddling with the balance and fade controls, it was obvious that, because of my seating position, the majority of sound was coming at me from the driver’s door. If I were at a live concert, I’d be sitting stage right, with the bank of speakers directly in front of me.

Turning on the surround sound made me feel like I was right in the middle of the concert hall. It’s difficult to pinpoint any one speaker. Most of the music was in front of me, with the reflection coming from behind, just as the engineers said it would. It’s quite an experience, and perhaps even a bit too much of one; after a few blocks, I realized – with a shock – that I was driving on “autopilot”. My attention was on the music, not on the crowded city street; it leads one to wonder how many collisions that first AM radio eventually spawned.

But car stereo is definitely not going away, and it’s never going to go backwards; even now, engineers are busy in Sweden, working on the sounds we’re going to hear five years from now.

The Dolby Pro Logic II system isn’t cheap – it’s an approximate $1,400 option on the company’s least expensive S40 – but it isn’t tough to ring up that and more at the aftermarket stereo shop, even before installation. And that gives you a system that’s added into the vehicle, rather than engineered in conjunction with it. Depending on the music and the listener, the difference can be subtle, and many people who simply want to listen to talk radio while they’re driving to work will probably view the system as overkill. The two lower-level systems are just fine and will undoubtedly be enough for most buyers. But for audiophiles, Pro Logic II – especially when equipped with the subwoofer available on some vehicles – can be the closest thing to sitting in the concert hall, centre stage.

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