Vario-roof makes SLK-Class the quietest compact roadster The standard-specification Vario-roof makes the SLK sports car from Mercedes-Benz the quietest-running model in its class. This has been proven by tests carried out in Stuttgart University's aeroacoustics wind tunnel using a revolutionary new concave mirror measurement technique. The Vario-roof's ability to absorb wind noise more effectively than a soft-top roof means that, when traveling at a speed of 140 km/h, noise levels inside the SLK-Class are up to six decibels lower than in other roadster models. This is the equivalent of halving the audible sound. The Vario-roof is a Mercedes-Benz invention that has granted the SLK a truly unique status among the sports car models in its segment since as long ago as 1996. It combines all the benefits of a hard top with the flexibility of a soft top. The fully automated transformation from roadster to coupé takes a mere 20 seconds or so: the Vario-roof flips out of the boot and arches forwards before closing over the occupants to protect them from the elements. What's more, the roof's sophisticated technology also ensures the low noise levels that soft tops are simply unable to offer and gives passengers a comfortable driving experience. This has now been confirmed by the results of wind tunnel testing, during which Mercedes-Benz engineers pioneered the use of two cutting-edge measurement techniques in unison to investigate the link between the wind noise at the roof's outer skin and the sound level inside the car. During testing, this state-of-the-art method of measurement was supplemented by the tried-and-tested artificial head technique: behind the wheel of the SLK sports car sat a dummy with an artificial head whose anatomically correct auditory canals are lined with condenser microphones. These special microphones allow stereophonic sound recordings to be made along with high-precision sound pressure and frequency measurements. The analysis of both measurement techniques clearly demonstrated the positive effect the sturdy Vario-roof has on the noise levels inside the SLK sports car. click to enlarge click to enlarge click to enlarge