The hazards of fighting fires are well known, with the best possible efforts made to protect firefighters from heat, smoke, and falling debris. Personnel wouldn’t think of getting on a fire truck without proper footwear, headgear, outerwear, and breathing apparatus. But, too many routinely expose their ears to high levels of sound.
For some, after a career risking life and limb in the line of duty, the residual impact of hearing loss caused by overexposure to loud sounds can last a lifetime. And for too many firefighters, overexposure to harmful levels of sound comes with the territory.
|1 The HD-15 package includes two electronic earplugs, a durable neck cord, seven different pairs of eartips to accommodate many ear shapes and sizes, a cleaning tool, filters that make sound clearer and prevent earwax from damaging the components, a filter changing tool, batteries, and a protective case. (Photo courtesy of author.)|
Here’s the good news. There’s a new product on the market, developed by Chicago-based hearing health company Etymotic Research, which not only addresses the need to be protected from loud sounds but amplifies quiet sounds as well. This “wearable technology” is called the Etymotic HD-15. It fits securely in the ear and adjusts volume automatically, sensing the changes in sound levels.
“The HD-15 is designed to give firefighters, police, military, and corrections officers a unique advantage,” says Etymotic’s director of audiology, Dr. Gail Gudmundsen. “While wearing this product, users have natural hearing until sounds exceed safe levels. As soon as hearing is at risk, the devices automatically become hearing protectors. If a blast occurs, there is instantaneous protection. Natural hearing is restored when sound levels return to safe levels.”
Etymotic Research received the Safe-in-Sound Award for Innovation in Hearing Loss Prevention given by the National Institute for Occupational Safety and Health (NIOSH) and the National Hearing Conservation Association.
HD-15 electronic earplugs use a new version of the Etymotic K-AMP® integrated circuit from the 1990s. The transducers are high-definition, balanced-armature drivers, and high-sensitivity microphones. Their bandwidth is 40 Hz to 16 kHz.
They’re also failsafe in the sense that for sudden, loud spikes in level, the devices are limited above 118 dB. Peak sound pressure levels above 118 dB are reduced to safe levels by the output limitation of the circuit. Because these bursts are so short-on the order of a few milliseconds-the clipped transients are safe. The sound reduction is instantaneous, so hearing is protected from intense transients. A gun blast of 140 dB, for example, cannot be reproduced. It sounds like a normal gunshot but is drastically reduced in level. The nearly instantaneous recovery time of the circuit also means no fidelity loss.
The product includes two electronic earplugs, a durable neck cord, seven different pairs of eartips to accommodate many ear shapes and sizes, a cleaning tool, filters that make sound clearer and prevent earwax from damaging the components, a filter changing tool, batteries, and a protective case.
Etymotic recently asked an FDNY lieutenant to test a pair of HD-15s and report his results. He says, “Once you get used to [them], the HD-15s are very useful and my overall experience was positive. I think the tip selection is terrific. I had no problem finding a decent fit with the triple flanges. I usually get good result from this type of tip. My left ear has an odd shape or angle, but it wasn’t an issue. I also thought the toggle switch for the different modes was useful. The more I used it, the easier it became.
“I find the sound quality to be fantastic. They amplified just the frequency I needed to hear-voices mostly. The clarity is top notch; I had no problem understanding the dispatcher or my chauffeur while wearing them. Overall, I think the HD-15s are a great product and I plan on continuing to use them. We protect ourselves from the hazards we face on the job every day but sometimes don’t make allowances for a noisy workplace. It’d be a shame someday, when it’s all over, to be left with a hearing impairment, especially when something as simple as hearing protection can make the difference. That said, we can’t use a product that blocks our hearing or limits performance in any way. That’s why this product is so interesting. I didn’t lose my ability to hear and, in most cases, was able to hear better.”
As the trickle of “wearable technology” turns into a stream and then a torrent, devices that aid human senses like Etymotic’s electronic earplugs are sure to find application in a variety of noisy settings.
PAUL IRWIN is a freelance writer based in Westchester County, New York.