When you close the door of a luxury sedan, the resulting deep, satisfying thud feels like an absolute guarantee of safety and superior craftsmanship. But that precise sound is entirely artificial, engineered over thousands of hours. Before the 1980s, car doors sounded like cheap tin cans snapping shut. As safety regulations increased, manufacturers realized that consumers did not judge safety by crash test ratings, but by the tactile, auditory feedback of the vehicle's hardware. This fasci...