Posts Tagged ‘hearing’

This sound is on fire

Many aspects of a firefighter’s work are not quite like the movies, and locating each other is one of them, according to a recent story from KUT News in Texas.  Visibility is poor or nonexistent in a real fire, so firefighters often have to rely on sound rather than vision.  A Personal Alert Safety System (PASS) is a device that emits a loud audible alarm if the wearer stops moving for more than a few seconds, allowing colleagues to come to the rescue.  Researchers at the University of Texas at Austin are working on ways to improve this system, which despite saving many lives doesn’t always work as well as it could.

For starters, an active fireground is a loud, noisy place, from things like sirens, power tools, engines, and the fire itself.  But beyond that, heat can do funny things to sound—hotter and colder parts of a room make sound travel faster or slower, and these changes in the speed of sound can actually bend sound waves that would otherwise travel in a straight line.  (Similar effects occur outdoors when the air temperature varies with height, such as being able to hear campers far away across a lake that cools the air.)  This heat refraction can wreak havoc with audibility and locating the source of a PASS beacon.  The current UT research will provide valuable insight into the sensory environment within a fire scene, and how compensation might be made for some of these acoustic challenges.

 

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Just how speedy is sound at the Olympics?

Well, it turns out not fast enough!  Years ago, in addition to a traditional starters pistol, Olympic officials started placing loudspeakers behind the athletes so that the sound would reach each athlete at the same time.  It turned out however that the athletes would continue to wait for the sound from the actual starters pistol to arrive.  Even with the loudspeakers, the speed of sound was still slowing down the athletes furthest from the starter pistol.  While we are talking about tiny fractions of a second, with Olympic runners and swimmers, it really makes a difference.  Starting at the Vancouver winter games and this summer in London, they are using a silent pistol that is completely electronic and generates a beep from the loudspeakers only (although it does make a flash).

omega110.jpg  False start: Usain Bolt was caught out in Daegu last summer

[via The Atlanticdailymail.co.uk]

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Telecool

HEARING LOOP INSTALLEDThis week the New York Times brings a promising update on the increasing adoption of the telecoil, a technology that promises to make life much easier for those with hearing impairments.  A hearing aid or cochlear implant that includes a telecoil can directly pick up the audio from a sound system, whether for a theater or a school or even a subway booth clerk’s microphone.  The signal is beamed to the telecoil via an audio induction loop of wire permanently installed in the floor; when the listener’s hearing device is trained on this signal, it eliminates the extraneous background noise and reverberation that can make intelligible listening a challenge even with a modern hearing aid.  The listener has effectively “plugged in” directly into the source—and without the social stigma that can hinder adoption of more obtrusive external listening devices.

The concept has been around for decades and is widely adopted in parts of Europe—there is a telecoil transmitter in the back seat of every London taxi—but it is only recently gaining a foothold in the US.  With the greying of the population and the fact that more than 30% of people over the age of 65 are affected by hearing loss, the ability to make clean audio directly accessible to the ear holds “clear” potential!

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Did your airport full body scan include your ears?

Your ears may be used for more than just hearing sounds.  Did you know that the top part of your ear does not change shape as you get older? And that someday it may be used to identify you?  According to Technology Review, researchers at the School of Electronics and Computer Science of the University of Southampton are working on it.

 

 

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Keep this quiet: Wednesday is International Noise Awareness Day

April 28 is the 15th annual International Noise Awareness Day, an event promoting awareness of the dangers of long-term exposure to noise.  Founded by the Center for Hearing and Communication (a not-for-profit organization established in New York in 1910), the event aims to raise awareness of the impacts of noise on day-to-day life worldwide.

As part of the event, the public is encouraged to observe a “Quiet Diet” — 60 uninterrupted seconds without noise from 2:15 to 2:16 p.m. this Wednesday.

Most New Yorkers are all too familiar with excessive noise and its impacts on hearing, health, stress, and learning. This year’s event has already garnered some local press, and we hope that greater awareness of noise leads to a “quiet diet” that the city can enjoy more than once a year.

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Tiny ears, big concern

As professional listeners, acousticians are trained in the dangers of noise-induced hearing loss, which is both cumulative over the years and basically irreversible.  Still, nearly anyone with ears understands that loud noise is bad for hearing, and has probably felt the after-effects of noise exposure after a rock concert or a night out.  But what about people too young to understand, or to recognize the physical sensations caused by overexposure?

This week, the New York Times examines the need to protect babies and young children from overexposure to noise.  Noise that is uncomfortable to an adult can be physically damaging to a child, whose smaller ears receive sound pressure with greater impact and sensitivity.  Protecting young ears usually requires earmuff-style protectors, since earplugs are ill-fitted to small ears (not to mention a choking hazard).

The article overlooks the danger of noise exposure from mass transit (including the hometown New York City Subway).  Subway noise levels at the platform can exceed 100 decibels near a curved track or express train—a level that will damage even adult hearing with frequent exposure.  Parents that frequently use the subway with their children should take steps to protect them from noise, since even slight hearing damage as a child will be carried for a lifetime.

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