Zero
decibels (dB) is where sound begins, like hearing a mosquito 10 feet away. A pin
drop comes in around 15 dB, conversations rate around 60dB, an airplane taking
off around 120 dB, a nearby subway car or gas mower around 100 dB and music on
digital devices from 88 to 115 dB. 120 is the danger zone. A jet’s sonic boom
for instance produces around 212 dB. 89 dB is the number considered safe for
listening to music.
Studies of Music Player
Users
According
to one European study, hearing loss comes from a combination of loud and long.
If you like to listen to music at a high volume and do so for an hour a day
each week, that will affect hearing loss within five years. These numbers put millions
of Europeans who use music players at risk. Another study of New Yorkers who
used digital music players found a listening average of 18 hours per week and
some up to 70 hours weekly.
Hearing Loss for Musicians
A
study of lifelong musicians showed that they fared better than average as they
aged. They still faced a problem detecting quieter and quieter sounds but they
were able to hear words against background noise and recognize different sound
frequencies, likely due to regular use of their auditory system.
Development in Limiting
Volume
A
company named dB Logic has developed a system to limit volume on headphones.
The system adjusts loudness when it continually measures over 85 dB. At that
level, the U.S. Occupational Safety and Health Administration mandates hearing
protection for workers, say in a factory.
Technically,
a tiny transformer increases the voltage that operates the transistors that
control volume. In other words, soft passages play back at full volume and
louder ones exceeding 85 dB are undetectably decreased in volume.
Extra Problem with Earbuds
Earbuds do
expose listeners to more sound. Apple’s iPod manual includes a warning to users
about the danger of hearing loss. The Royal National Institute for Deaf People
in the UK also warned that more than two-thirds of young people who use earbuds
and personal music players may suffer early hearing damage. Another 2005 and
2006 study of U.S. adolescents aged 12 to 19 showed that one in five had
hearing loss, more males than females. Another possible effect of playing music
loud for long hours is tinnitus. Doctors specializing in this field say that
when hearing loss happens to teens (by the time they reach their mid twenties),
the effects are irreversible.
Sources:
Stephen Cass, http://www.technologyreview.com/computing/38637/?p1=A2
MIT
Stephen Castle, http://www.nytimes.com/2008/10/13/technology/13noise.html,
New York Times
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