Testing the mark Levinson System in the Lexus GS
The Lexus brand has been synonymous with premium automobiles since its inception. For those of us who appreciate fine automobiles and great music, it's nice to see that Lexus applies their quality of engineering not only to the engine, chassis and interior, but to the audio system as well. I had a chance to audition the factory audio system in the original GS back in 1996 and recall being impressed (for OEM audio standards), so I was eager to listen to the new Mark Levinson Discrete 5.1 Surround Sound System in the new 2006 GS to see how things have advanced in last 10 years.
Source material and signal processing technology has definitely improved in the audio world. High-end products like DVD-Audio players and surround sound processors have been trickling down to aftermarket car audio over the last several years and recently made it into OEM car audio. The Mark Levinson system in the GS is one of the latest, upper-echelon OEM audio systems that provide a home-theater-type experience. It can play DVD-Audio, DVD-Video and DVD-R formats (both Dolby Digital and DTS) with "Discrete 5.1 Surround Sound reproduced by a 7.1-channel surround sound architecture." When the GS is safely parked, the video portion of the DVD is viewable on the touchscreen monitor. An 11-channel Mark Levinson processor/amplifier puts out 330 watts (all channels driven, 20kHz to 20kHz at less than 0.1% THD) through four tweeters, five midranges, four midbass drivers and one subwoofer. The tweeters and midranges use neodymium magnet structures and proprietary metal-cone technology.
Designed to address issues of reproducing multi-channel sound inside the automobile, the Mark Levinson Surround (MLS) audio software can also create a "multi-channel listening experience" from 2-channel sources like FM, CD and satellite radio. Digital signals are transmitted from the head unit to the amplifiers using SPDIF (Sony Philips Digital Interface Format), capable of 24-bit word lengths, to preserve signal quality and avoid induced noise issues. To help address the varying sound characteristics of the different sources, each source has independent settings for tone controls, MLS and ASL (speed dependent volume and tone control).
After loading up some test tracks (CD and DVD Audio) into the 6-disc in-dash DVD/CD changer, I was immediately impressed by the smooth tonal balance of the system. With most factory audio systems, an unwanted peak or dip in frequency response will quickly reveal itself, but this system gave me the impression of an IASCA competition sound-quality car with many hours spent tuning to achieve an even frequency response. Not surprisingly, engineers spent over 1,000 man-hours tweaking the Mark Levinson system for this GS. The dash-mounted midrange drivers were smooth with good detail. The midbass drivers in the front doors delivered good punch. With some bass-heavy rap beats, the midbasses began to distort from reaching their physical limits at high volumes, but performed well with the other tracks. The tweeters were good but a little subdued, making the cymbals on some tracks sound veiled. The 10" ML subwoofer had impressive output and low-end extension at low and moderate volumes, but the output started to taper off at higher volumes. The cast aluminum basket found on the subwoofer is extremely rare for an OEM subwoofer and has 100 watts of the 330-watt amplifier dedicated to it. I'm sure that the Lexus and Mark Levinson engineers never intended to create an SPL monster with this system, but most audioenthusiasts will be left yearning for more low-end output.
While auditioning with the MLS processing turned on, the center image was well focused and natural, whether the source was a 2-channel CD or multi-channel DVD. The stage width seemed a little narrow, perhaps due to the tweeters' being arranged closer to the center (of the mid/tweet combo) for the left and right dash speaker locations. With the MLS processing turned off, the stage width improved slightly, but imaging and staging suffered.
Considering all the usual limitations placed on OEM audio engineers (e.g., space, safety, reliability, cost, etc.), the performance level of this Mark Levinson system is outstanding. Straight from the factory, this system will completely satisfy many GS owners and, in some cases, it may outperform their home audio systems. The only drawback to systems tuned for "smooth" sound is that some types of music can seem a little lifeless or dull. Like most automotive enthusiasts who don't own a car without suspension, wheels, tires and exhaust upgrades, some audio enthusiasts probably won't be satisfied without tweaking some things to their tastes. New GS owners should be forewarned that the ML system, unlike many cars that almost need mandatory audio system overhauling, is already so well dialed that upgrades must be chosen very carefully in order to not degrade the sound quality.
Enhancing the sub bass of the Mark Levinson system would be the least complicated upgrade. A top-quality subwoofer (or two) and powerful amplifier would be necessary to make the "upgrade" an improvement. The trunk area of the GS has deep side pockets in the rear corners, inviting a nice subwoofer system to call it home. This area would be optimal for subwoofer placement because of its loading characteristics. Upgrading the tweeters/tweeter placement would be another possibility, but "improvements" would likely be highly subjective, expensive and time consuming because of the complexity of the system. High-end OEM sound systems have definitely narrowed the gap between OEM and aftermarket sound quality in the last 10 years, making it harder for us in the aftermarket to make significant improvements without doing our homework. Although this creates a challenge for the aftermarket, it benefits the audio enthusiast and consumer because the competition between OEM and aftermarket pushes both sides to create better sounding products.