Mercedes-Benz is now extending its PRE-SAFE® technology with PRE-SAFE® Sound.It will be debuted in the new E-Class, model series 213, available since 2016.The system is the first to harness a natural reflex to condition the ear – when a collision is imminent – for the loud noise that is anticipated from the impact. If an impending collision is detected that would be expected to produce a loud crash, the vehicle’s sound system plays. This causes the stapedius muscle in the ears to contract, which for a split second changes the link between the eardrum and the inner ear and so better protects it against high acoustic pressures. Most importantly, the reflex reduces the damage to hearing.
That may sound simple enough, but as is so often the case with advanced technology, there is a lot more to it than meets the eye. "People have long been aware of the stapedius reflex and its protective effect," says Wilfried Bullinger, who works in Mercedes-Benz Cars development on innovative occupant protection systems. "To make sure you trigger the reflex, however, you normally need high sound pressures, typically around 100 decibels. This would be like listening to a trumpet playing from around one metre away. But this volume would definitely be too high for use in a car." Then the experts discovered a way of tricking the body.