While most of us probably can’t buy the new 2017 Mercedes-Benz E-Class (suggested retail price: $52,150+), it does pack some cool new tech you might want to know about. According to IEEE Spectrum, when this Mercedes senses the car is about to crash, it unleashes a burst of “pink noise” causing a muscle in the inner ear called the stapedius to contract and ready the eardrum for the deafening noise. of the accident itself.
Pre-crash safety devices in cars are not new (IEEE Spectrum cites seatbelts that tighten instantly or sunroofs that close instantly when a crash is predicted), but the notion of pink noise as a means of protecting hearing is new. Mercedes describes this feature as “Pre-Safe Sound” (you can hear it yourself in The Mercedes video).
IEEE Spectrum reports that the pink noise used is around 80 decibels – “about equal to that of a dishwasher and completely safe”. Car crashes, the IEEE explains, are potentially deafening and typically register around 145 decibels. “Even worse – and this part is not emphasized by Mercedes-Benz or any other automaker – is the noise created by the near-instantaneous deployment of the airbag: approximately 165 dB,” writes Philip E. Ross. “An estimated 17% of people exposed to airbag deployment suffer some degree of permanent hearing loss.”
What is pink noise?
Most of us have heard of white noise; white noise machines and apps flood rooms with something akin to old-fashioned broken TV static. Machines are often used as sleep aids and to mask tinnitus. Technically speaking, white noise is really a combination of all the different sound frequencies.
Pink noise refers to a broad spectrum of frequencies in which power is inversely proportional to frequency. If you’ve skipped college physics and listened to a lot of records instead, you might understand better that pink noise uses different octaves of the same pitch in which each of the octaves has the same frequency power as the other. For this reason, many people hear pink noise as “even” or “flat”, but the difference between white noise and pink noise is difficult for most people to detect. mercedes describe in its marketing materials as “much like the diffuse noise of traffic, breaking waves, or a waterfall”.
(Just think how you might freak out hearing ocean waves in a car accident if you weren’t aware of this feature, though.)
Can pink noise protect against hearing loss?
Mercedes’ use of pink noise raises the question of whether the same technique could be used to trigger ear muscles to protect the inner ear from other loud noises and prevent hearing loss. The threshold to trigger the stapedius reflex is around 100 decibels, which is quite loud. Pink noise, however, allows that noise to spread across the spectrum and doesn’t feel as harsh to our ears. However, this only triggers a rapid muscle reflex lasting about a second.
In other words, loud bursts of pink noise probably couldn’t prevent hearing loss over time or in many other cases. In fact, it could be detrimental to hearing if used loudly over time. However, some hearing aids use pink noise (as well as white noise, high-pitched noise, and other noises) to help people who suffer from tinnitus to reduce or diffuse the ringing in their ears.
Protect your hearing, protect your brain
New pre-safety measures like the deployment of pink noise in the Mercedes E-Class could usher in a new level of hearing protection safety in automobiles. And perhaps other uses for the technology can be developed and employed beyond high-end vehicle safety (for example, perhaps workplaces prone to loud bursts of sound could study d other uses of pink noise bursts or that the military might use the technology where high explosives and firearms are used).
Considering the link between hearing loss and dementiaas well as the social isolation experienced by many people who have lost their hearing, any additional measure that protects hearing seems worthy of research and investment.
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