How Mercedes used the Force to turn the new SL-Class into a concert hall

While technology in new cars has finally begun to catch up with modern times over the past few years, there's been one harsh exception: factory stereos. With a few exceptions, stock head units and speakers usually require aftermarket tweaking to achieve sonic nirvana. Mercedes engineers are having none of that.

For the past seven years, they've been working on an innovative subwoofer set-up called FrontBass which uses the metal chassis of the 2013 SL Roadster as a sound cabinet. To hammer the point home that the Three Pointed Star should be known for great sounds, Mercedes enlisted Skywalker Sound - the audio arm of George Lucas' film empire -- to custom-engineer a Signature Sound disc of pop classics aimed at highlighting the roadster's surround sound capabilities.

Although FrontBass currently is only available on the pricey SL, it will soon come to most of the Mercedes line-up. In its current incarnation, the new audio system is available in three tiers: with non-branded speakers and electronic parts, Harman Kardon gear or a 940-watt Bang & Olufsen outfit.

Mercedes trotted out recently at Skywalker Ranch, the sprawling Marin County, Calif., compound that Lucas bought after "Star Wars" profits started rolling in. Although the great bearded one didn't make an appearance, a few of his top audio people gave a tour of the cavernous recording facility where a prototype SL sat disguised as the team massaged songs such as Lady Gaga's "Poker Face" and Seal's "Amazing" using the original master tapes provided to Mercedes by each performer. The procedure was comically simple: Tweak the tune. Run to the car and play the disc. Mull. Tweak some more. Test some more.

For months on end.

"Cars are really a great place for people to experience music," says Leslie Ann Jones, Skywalker Sound's director of music recording and scoring and the ears responsible for the disc, which is available only to new SL owners.

"You're in a static position, for hours often, thanks to today's traffic. So our job was to take these hit songs and re-record them so you could hear them in a new way, unique to this car," says Jones, daughter of famed 1940s bandleader Spike Jones. "The only disappointing thing was our prototype SL had no engine. So I've never even driven it."

A few words now about FrontBass, which required nothing less that a multi-year redesign of the two-seater's body. The system's dual 8.6-inch subwoofers have moved from the door panels to just above the driver and passenger's feet, each one now poised at the head of a cylindrical structural piece that serves as a metallic resonance chamber for ultra-low frequencies. That move also allowed Mercedes engineers to set the midrange speakers and tweeters higher on the door panels than in previous models, reducing the chances of thighs absorbing those precious sound waves. Rounding out the system are speakers behind the front seats, for a total of 14 discreet units in all.

"Stereo sound is not natural, but sound surrounding you is, and that's what we wanted for this system, to envelope the passengers in music," says Herbert Waltl, CEO of mediaHYPERIUM and a senior producer on the Signature Sound disc, which actually isn't a CD but rather a DVD whose various audio channels were used to divvy up the sound.

So just what does the SL's system sound like? A two-hour drive looping around the farmland of West Marin provided the answer. In a word: revealing. Take Gaga's "Poker Face" as an example. When compared with a standard CD track, the Signature Sound mix seemed to blast out of every corner of the interior -- backing vocals surprising the listener from the rear, while a thundering bass sound hit your gut without the usual accompaniment of rattling switch gear and paneling. The vocals danced across the dash, while guitar, bass and keyboards could be picked out individually instead of being reduced to one giant instrumental mud pile. And that's with the top down.

But a more revealing moment was still to come. Riding shotgun with me was Robert Harley, editor of high-end audio bible The Absolute Sound. Harley nodded as the Signature Sound disc played, impressed with the system's ability to deliver a better-than-average listening experience despite the presence of road and engine noise, wind and the occasional motorcycle zipping past. But then at a stoplight, he quietly ejected the Skywalker Sound compilation and popped in a few discs that he uses for testing systems that often cost as much as a small house.

The effect was immediate. Harely's cache includes a CD by jazz organist Joey DeFrancesco called "Part III" features absurdly low notes that cause most subwoofers to botch the reproduction. But the dual FrontBass woofers kept up admirably without a hint of distortion even at high volume. When Harley slipped in a Grammy-winning recording of Count Basie and his orchestra, "88 Basie Street," the entire band seemed to materialize in front of driver and passenger, with Basie's signature piano flourishes rendered crystal clear as the SL 550 blasted along Tomales Bay. I glanced at Harley, whose eyes were wide open. That said something considering he's currently testing home speakers called Magico Q7s that cost more than the most expensive SL.

If you've got more than $100,000 to spend on a two-seat roadster, then you have enough to improve the sound system of a Mercedes-Benz drop-top coupe. But the rewards of a luxury car should include knowing you don't have to.