Few luxury-grade convertibles go to as much trouble as the 2011 Mercedes-Benz E550 Cabriolet to make sure that the pampered driver and passengers are cosseted. The richly appointed ragtop has a standard feature called AirCap that consists of a speed-sensitive air foil that separates from the top edge of the windshield and a mesh screen that rises from between the rear seats to quiet the open cabin and keep it draft-free. And if the driver and passenger get chilled they can switch on the AirScarf, neck-level seatback vents that blow warm air on their delicate de'colletage.
Even the Harman/Kardon surround-sound system seems tuned for top-down tunes, judging from a recent week's worth of riding in the E550 drop-top. While I test all audio systems sitting still to form a baseline for comparison (but also take them on the road to see how the sound holds up against the driving noise), my time behind the wheel fortunately coincided with some sweet Indian summer weather. So I had plenty of opportunity for open-air listening -- and to determine that the E550 convertible's Harman/Kardon system performed well whether the interior had a roof over it or not.
The Setup
The E550's optional Harman/Kardon system consists of 12 speakers powered by 425 watts. The speakers include a 3-inch midrange in the center of the dash, a 6.5-inch midrange and 1.5-inch tweeter in each door, another 6.5-inch mid and 1.5-inch tweet in each rear side panel, two 3-inch rear-surround speakers in the rear deck that lifts to stow the convertible top and a 6.5-inch dual-voice-coil subwoofer. The only clue to the presence of the latter is a small rectangular-shaped grille between the two back seats.
The Sound
As with every system I test, the Mercedes-Benz E550 Cabriolet's system was subjected to about a dozen musical tracks I've listened to in literally hundreds of vehicles to check clarity/lack of distortion, tonal balance, timbre, tonal accuracy, soundstaging, imaging and dynamics. I also used non-musical tracks to further gauge soundstaging and imaging and to test for linearity and absence of noise. If you'd like more details on the audio-system testing process and the tracks used, jump over to the Edmunds.com article Sound Advice. As mentioned, I usually do subjective listening while sitting still with the engine running, but with a convertible it's, of course, also crucial to test the system while cruising with the top down.
The E550 Cabriolet's Harmon/Kardon system is about what you would expect in a car that cost almost 75 grand ($74,875 to be exact). Unfortunately for high-end automakers, it's also becoming an experience drivers can also expect in much less expensive cars since good sound -- and good technology in general -- is quickly trickling down into segments well below luxury category. Five years ago or so, this system would have been well above the average, whereas now it's only slightly above average.
While it had good stereo separation, largely accurate timbre and tonal accuracy, lively dynamics and exceptional soundtstaging and imaging, it also exhibited the Achilles' heel I find in many systems: boomy bass and harsh highs, which skewed clarity and tonal balance. This was especially apparent in the way that overly thick and often distorted low- and mid-bass notes marred the otherwise smoothness of a certain section of a song and the way that horns blared instead of sounding accurate.
The Harman/Kardon system made up for these deficiencies by producing a very spacious soundstage and creating credible sonic images. Width-wise the soundstage extended past the confines of the car, and this was without the Logic7 processing engaged. With the synthesized surround switched on, the soundstage was even more expansive, although to my ears it wasn't worth it since it also added an artificial quality to the overall sound -- and emphasized the bass so that it was even boomier.
But I also found that I preferred the sound of the system with L7 turned on when the top was down. Maybe it's because road noise masked any artificiality, or maybe because the extra bottom end the processing produced mitigated the cabin gain -- an audio phenomenon common in an enclosed space such as a car -- created when the top's in place. Or maybe because it was tuned to have better top-down sound with the processing engaged.
Regardless, the open-air sound was impressive even at high speeds.
Equally remarkable was the system's response with DVD-Audio discs. The high-resolution format seemed tailor-made for convertible cruising, and its enveloping ambiance was as almost as palpable as warm breeze from the Air Scarf feature. But sitting still, tunes on DVD-Audio discs were still a bit bass heavy and brittle on the high end.
The Sources
The Mercedes-Benz E550 Cabriolet has a six-disc CD/DVD changer in the dash that also included AM/FM/Sirius and HD radio as well as a 6GB hard drive for storing music files that can be ripped from CD (only). The vehicle has a PC card slot that no one I know uses, but it doesn't have Bluetooth audio that more people using for convenience sake.
iPod/MP3 player integration is via Mercedes' Media Interface, which like the Harman/Kardon system itself is part of the $4,000 P01 option package, which also includes the Air Scarf, heated front seats and backup camera. (On our test car, the P01 features were included with the $6,450 P02 option package). The Media Interface is a set of proprietary plugs, each one specific for aux-in, USB or iPod 30-pin connectivity, but our test car only came with the one for iPod.
iPod access in the E550 Cabriolet, like many Mercedes-Benz, is via the company's Comand system: a combination of a 7-inch in-dash screen and a rotary center-console controller, along with center-stack and steering wheel controls. The arrangement of the icons along the top and bottom of the screen that are used for most iPod menu functions aren't the most intuitive, but they get the job done with not too steep of a learning curve and minimal distraction once you have it dialed in. And the center-console rotary controller is handy once you get used to it -- and quit confusing it for a volume knob and skipping ahead a track just when you're ready to crank it up.
What We Say
More high-end European automakers are hooking up with high-end European audio brands like Bowers & Wilkins and Bang & Olufsen, and Mercedes-Benz has also recently jumped on the B&O bandwagon for its C-Class and AMG models. While Harman/Kardon may not have the luxury luster of an audio company from the Continent the system in the 2011 E550 Cabriolet can easily hang with those with an ampersand in their names and on the speaker grilles. I found this out firsthand a couple of weeks later when I was in a 2011 Jaguar XKR convertible with a B&W system. The H/K system in the Mercedes-Benz E550 Cabriolet easily sounded much better when it counts most: The sound wasn't gone with the wind, as in the Jag.
The Scores
Sound: B+
Source Selection: B-
iPod Integration: B
Cost: C+
