Car Audio

Highway stripes are 10 feet long and 30 feet apart. That means one stripe every 40 feet. No one really knows how this fundamental increment of civil engineering came to be. Well, I’m sure somebody knows, but that person works in the historical division of the federal Department of Transportation.

This is a person to avoid at parties.

There are some wondrous synchronisms hidden in that white-stripe measure. At 55 mph, for instance, a car is traveling 80.66 feet per second, which means that two white stripes slip by every second. This tempo — 120 “beats” per minute — syncs up almost exactly with the best driving song ever, “Radar Love” by Golden Earring. Let us all now pause for a moment to remember the primer-gray Impala with burn marks in the ceiling we drove in high school.

Today, I’m driving Audi’s imperial battle cruiser, the S8 — an aluminum-bodied, laser-welded limousine powered by a direct-injection, 450-horsepower V10 reactor. It’s about 9 p.m. and I’m on Interstate 5 heading south toward Orange County. Traffic is light. The Audi’s blue-white xenon headlamps peel back the night. At this speed, the freeway’s reflective white stripes flash by about 153 beats per minute — you do the math. KCRW’s “Metropolis,” the Santa Monica FM station’s sublime techno-electronica-trance program, is in mid-rave.

And here it is, one of those perfect driving moments: The pace of car and the tempo of the music come into register and it seems as if the movie playing in my head has just gotten an awesome new soundtrack. The steady thrudding of the bass comes into phase with the white lines. The Audi’s harmonics — engine, tires, wind and exhaust — melt into the droning house textures. I experience automotive synesthesia. The night has a steering wheel. Where does the road end and the music begin?

This is by far the trippiest, most out-of-body experience I’ve ever had in Orange County.

My gateway drug?

The Audi S8′s optional Bang & Olufsen sound system, a 14-speaker, 1,000-watt, twin-amplified mega-system that floods the cabin with crystalline sound and aural imaging that is a bit hallucinatory. Who knew you could get a whole chamber quartet in the back seat?

The B&O system is astonishing in many ways — it is, for instance, astonishingly loud. And, as is traditional with B&O, there’s a bit of theater involved. When you start the car, small cylinder-shaped tweeters rise out of the dashboard. These speakers use Acoustic Lens Technology — I can’t really explain it here, but I thought you might savor the name.

In another way, the B&O system is typical, as more luxury carmakers hook up with companies known for their audiophile home equipment.

Lexus, for example, has a co-branding arrangement with Mark Levinson (a division of Harman International). The Mark Levinson Reference Sound system in the LS460 is a sonic Howitzer: 450 watts, 19 speakers, 15 channels.

Likewise, Acura enlisted Grammy-winning producer-engineer Elliot Scheiner to develop sound systems for the RDX, MDX, TL and RL. These systems combine multi-channel playback with high-definition DVD-Audio.

But, as far as I can tell, the B&O system in the S8 has the most horsepower (wattage) of any factory-installed audio system.

The importance of wattage is hotly debated among audiophiles. It’s generally understood that high-watt amplifiers have lower distortion at lower sound levels. It’s also true that there is a disconnect between wattage (a linear scale) and sound pressure (logarithmic). A 1,000-watt sound system at max volume is not twice as loud as a 500-watt system, all other things being equal. It is, however, loud enough to make your brain exit your ears.

Here are two rules of thumb as you shop for high-end car audio. First, more speakers are better. The more speakers, the more uniform the sound field created in the cabin, the more optimized the signal to any individual speaker, the better the surround-sound spatial imaging and the finer the tuning of the signal to the cabin’s acoustic properties. Second, by the time you reach that stage in life when you can afford a six-figure luxury sport sedan, your hearing is lousy, so don’t fret about the first rule.

The trouble with high-end audio in automobiles, of course, is the source material.

FM radio, for example, has frequency response (the range of sounds able to be reproduced) between 50 hertz and 15,000 hertz, well short of the 20-hertz to 20,000-hertz range of conventional compact disc recordings.

Satellite and high-definition radio are better, but you have to pay monthly for the former and have limited station options with the latter. The high-density digital recording formats — DVD-Audio and Super Audio CD — are expensive and their music catalog limited.

In five years, the in-dash six-disc changers that are de rigueur now will be rendered obsolete by a variety of portable media, from iPods to USB flash memory. So, rip your Golden Earring CD while you can.

What won’t change is that the quieter the car, the better the sound. The current generation of high-end audio systems spends much of its bandwidth competing with the ambient environment. Despite all the noise abatement built into the S8 — the air suspension, acoustic glazing, girder-stiff aluminum chassis and 100 other details known only to Audi’s oscilloscopes — the cabin still has a minimum 60-decibel sound level. Quiet, yes, but not quiet enough.

The best sound systems on the road — found in the Acura RL and TL — use active noise cancellation, a technology that produces signals 180 degrees out of phase with the background noise, cutting down aural clutter. Bose, which pioneered the technology, is putting it into its own high-end OEM systems.