Sound engineering at BMW goes way deeper than just isolating the cabin and removing every annoying rattle and squeak. They spend a lot of time and effort designing and perfecting every beep and clunk you hear in the car. BMW has a team of sound expert who professionally create the bongs for Bimmers, MINIs, and Rolls-Royce cars.
They even go as far as balancing the sound in the front compartment with the sound in the back by channeling it through the speakers. You may not notice it while driving, but this whole sound business plays a major role in providing you with a fine time behind the wheel.