Car makers have developed a myriad of technologies to keep you safe in the event of a collision. Airbags, seat belt pre-tensioning, and other features can reduce the damage done in a car accident, but what about your hearing? Crashes are loud enough to cause damage to the inner ear, but Mercedes-Benz has a potential solution. Its latest vehicles play a burst of pink noise to insulate your ears from the sound of an accident.

This new feature is part of the Mercedes-Benz Pre-Safe system. That encompasses various features tied to the car’s built-in sensors. When the car detects that an impact is unavoidable, it takes steps to prepare. One of the things it now does is play a burst of pink noise through the speakers. Mercedes-Benz has included a special audio processing chip in the new 2016 E-Class for this purpose.

The goal of this sound is to trigger the stapedius reflex in your ears. This refers to the stapedius muscle, which moves a bone called the stapes away from where it contacts the inner ear. This lessens the amount of energy that can be transferred, but it only lasts a second. This reflex is triggered by loud noises, allowing the ear to protect itself from damage. The Mercedes-Benz system is aimed at triggering this reflex immediately before a crash, and it does it with pink noise.

The threshold for triggering the stapedius reflex is about 100dB, which is fairly loud on its own. That’s too much sound to be blasting at people on purpose, but pink noise has more energy than a single tone because of the way it’s spread across the spectrum. It can have lower volume but still trigger the stapedius reflex. Mercedes-Benz tested the system and found an 80dB burst of pink noise was effective in preparing the ears to cope with loud noises associated with collisions. Mercedes-Benz hopes to expand Pre-Safe sound to more vehicles later.

Author: Ryan Whitam, Geektek