2006 Lexus GS 430/Mark Levinson Premium Surround System and Bang & Olufsen/Audi Advanced Sound System

Two takes on two approaches to high-end auto sound systems.

Virtually all of the Beolab 5’s innovations are currently being applied to the harsh sonic environment of automobiles. The initial beneficiary will be the 2007 A8 sedan, Audi’s flagship vehicle. The Advanced Sound System will consist of no fewer than 14 speakers and 1100 watts. While impressive, those figures don’t tell the real story.

While the speaker drivers are nothing unusual, their deployment is. Rather than mounting them in open-air spaces such as doorframes and parcel shelves, each speaker is treated to its own custom enclosure. There are midranges, woofers, and subwoofers, but the crown jewels of this set are the tweeters which, when summoned, rise ghost-like from the dash top. These units employ Acoustic Lens technology—exclusively licensed to B&O by its inventor Sausalito Audio Works—to disperse sound waves over a remarkably uniform 180 degrees. (B&O believes that the lack of a convincing soundstage that bedevils most car audio systems is caused by tweeters with inappropriate radiating patterns.)

The company also finds most car systems dynamically constrained due to the wimpy amps mandated by space limitations. To overcome the problem without filling the trunk with Monsoons, B&O turned to Icepower, its sister company. Icepower justly claims significant breakthroughs in the civilizing of Class D digital amplifiers. Its modules are small, powerful, run cool, and sound so good that they have been incorporated into some high-zoot amps offered by prestigious manufacturers whose names we’re not allowed to reveal. Not one, but every speaker in the Advanced Audio System gets its own Icepower amp, ranging in size from 28 watts for midranges and tweeters to 250 watts for the sub.

Finally, and perhaps most significantly, B&O attacked a raft of other challenges via the aggressive use of DSP. The company’s newly developed processor supports sixteen separate channels and uses fourteen of them to create an EQ, delay, and active crossover profile for each speaker. The objective is to calibrate the overall system response to its environment; to dynamically compensate for factors such as road noise; to upmix stereo sources to 7.1 channels; to provide listeners with an enveloping soundstage centered directly in front of them; and to best optimize, according to the user’s wishes, the listening experience for either the driver, both front-seat occupants, or the entire car.

The Acoustic Lens-equipped tweeter sounds as sweet in the Audi application as in the Beolab 5. Here, however, it must contend with the hump that forms the top of the instrument binnacle. Thanks to that acoustic impediment, tall listeners in the driver’s seat heard nearly all the sound emanating from the left tweeter. Those riding shotgun were rewarded with a naturally broad soundstage and excellent imaging. Shorter listeners reported essentially opposite results. In addition, there were obvious discontinuities between drivers (the speaker kind, not the people kind), and the back seat had yet to be optimized, so it was strictly off limits.

When confronted with these observed shortfalls, B&O’s engineers replied with acknowledgement and assurances that the problems will be addressed before the system’s September debut at the Frankfurt Auto Show. These pledges hold credibility. The assembled press was shown two prototypes: the latest and, for comparison’s sake, an earlier iteration. The progress manifested in the more recent version— with its significantly greater dynamics, deeper and more controlled bass, and smother overall response—was enough to convince us that the rate of improvement is swift indeed.