Diesel engines have a lot of advantages over their petrol counterparts, the most significant being their impressive fuel economy and monstrous torque. But there's one thing they don't have and that's the right sound. However, the BMW Group appears to have a solution for the problem - albeit in prototype form for now.
It's called Active Sound Design or ASD for short and it has been applied on two prototype diesel-powered models, a MINI Clubman and a BMW 635d Coupe.
ASD is an electro-acoustic system that makes use of microphones and the vehicle's sound system to change the engine's sound characteristics. The further enhance the acoustic experience, BMW's engineers also used different sound and vibration deadening materials in the engine bay and under the body of the car.