These are some frequency response measurements of the 2012 Mercedes-Benz GL-Class’s optional Harman Kardon in-car sound system. While its frequency response is far from neutral, this 12-speaker sound system is quite enjoyable to the ear. The sub-bass boost compensates for the engine noise, and the treble roll-off makes a non-fatiguing sound, which is especially appreciable for long road trips.
Front Passenger Seat
Overall, the Harman Kardon sound system in the 2012 GL-Class delivers good performance in terms of midrange neutrality, soundstage and spatial consistency. I strongly recommend keeping Logic 7 on and setting bass to -10.