As a rule, those gifted with a sensitive sense of hearing cannot expect much listening enjoyment in a roadster. Even good auto radios and CD players are disappointing under these arduous acoustic conditions.

Instead, in open-top cars, the music flies away with the wind; it frays and breaks up in all directions without its acoustic base – passengers generally have to be satisfied with a woolly “sound carpet”, or close the roof. Open-air pleasure and musical enjoyment could hardly be expected in a roadster. A great part of the blame for this lies with the location of the bass loudspeakers in the doors or under a seat. Mercedes-Benz now presents a solution to this conflict: the unique FrontBass system, which at last creates the conditions for a concert hall ambience in a roadster too. In the future new SL, the FrontBass system celebrates its world premiere.

Crisp bass sound from the footwell
The principle sounds simple: Instead of being placed in the doors in the usual way, in the new SL generation the bass loudspeakers are installed in the footwell in front of the driver and front seat passenger. This is not possible with traditional vehicle shell structures, but the two front longitudinal members in the front aluminium skeleton of the new SL provide the space needed for this arrangement. The loudspeakers are fitted directly in two openings in the firewall on either side of the footwell. Cavities in the longitudinal members behind the speakers act as resonating chambers. The outstanding inherent rigidity of these structural components results in ultra-precise low notes with extremely little distortion, right up to very high signal levels. In order words, the new SL features clear, crisp bass sounds with a high dynamic range as part of its standard equipment.

The position of these two independent closed bass boxes in the footwell permits the creation of ideal acoustic conditions. Because the firewall, the vehicle floor and the underside of the dashboard form a sort of funnel that focuses and concentrates the sound – a better sound performance is the result. The acoustic effectiveness improves significantly. The formula: low energy, lots of sound volume, saves energy of top of it all. This way, the FrontBass system also contributes towards a CO2 reduction.

Precise, brilliant sound
With the new FrontBass system, Mercedes-Benz not only revolutionises in-car bass sound reproduction – and in particular aboard an open-top roadster – it also creates the conditions for exceptional listening enjoyment. Since the bass loudspeakers now do not need to be installed in the doors, the disruptive acoustic vibrations typical of this configuration no longer occur. In addition to this, the sound experts have placed the mid-range and high-tone loudspeakers in the doors, the dashboard and in the vehicle rear optimally close to the waistline and thus almost at the same height as the SL occupants’ ears. This way they display a precise, brilliant sound quality. The experts speak of an exact stage reproduction with precise instrument representation and an equally precise spatial graduation.

Even the standard entry level FrontBass system creates a pronounced encircling sound feeling and an emotive sound experience, aided by the perceptible pressure wave from the footwell, independently of whether the vehicle roof is open or closed. Norbert Niemczyk, responsible for the new FrontBass system at Mercedes-Benz: “Our objective was not mere sound volume – although in this respect, too, the system performs amazingly – but a clear sound instead, one that never becomes “mushy”. We have achieved this. All those who experienced the sound with the FrontBass system for the first time got out of the car with a big smile on their face – in-house we call that the FrontBass smile.”

Friendly to the surroundings: focused sound
Acoustic enjoyment of the highest level is part of the programme in the new SL both with closed and with open top. As the FrontBass system focuses the sound, the powerful sound is concentrated on the vehicle occupants – the surroundings are significantly less disturbed than is the case with conventional sound systems. Apart from this, the amplifier automatically controls the loudspeakers in a different manner depending on whether the passenger compartment is closed or open, according to the acoustic conditions, in order to create the best possible sound.

FrontBass is always on board
The FrontBass concept is the standard basis in every version of the new Mercedes-Benz SL. In the entry-level variant it is coupled with an amplifier that is integrated in the COMAND head unit with an output of 4×25 Watts, two FrontBass loudspeakers with a diameter of 217 mm, two two-way systems for high and mid-range tones in the doors and two more mid-range speakers in the rear.

The optionally available Harman Kardon Logic 7 surround sound system in conjunction with the FrontBass system are a further enhancement and a musical delicacy of concert hall quality. The heart of the matter is a Class D amplifier with a total output of 600 Watts and digital signal processor (DSP) for ten audio channels. The two FrontBass loudspeakers and six two-way systems provide an even more precise and better defined sound reproduction quality.

And finally, the absolute summit is the also optionally available Bang&Olufsen sound system. Its two Class-D ICE power amplifiers with a combined output of 940 Watts deliver exclusive audiophile high-end sound to the vehicle via their integrated digital signal processor and its 12 high-end loudspeakers.

Bodyshell tuned to FrontBass
In order to realize the FrontBass concept, the sound specialists worked in close cooperation with the bodyshell designers right from the very first planning stage. A small welcome side effect: since the FrontBass concept made the loudspeakers in the doors superfluous, the designers were able to use the space made free in the doors for additional stowage compartments.

Source: Daimler AG