Heard about this today on the news today. I think it would be important for
us tuners. Check it out.
Jack Houweling
http://www.sfgate.com/cgi-bin/article.cgi?file=/c/a/2005/09/22/DDGKUER3M323.DTL
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Thursday, September 22, 2005 (SF Chronicle)
Play it loud, and you may pay for it. A warning to all about those earbuds.
Digital devices reproduce music so cleanly, listeners are less likely to
turn it down
Joel Selvin, Chronicle Senior Pop Music Critic
Somebody grooving to the new Coldplay album on their new iPod or other
personal listening device may not be thinking about hearing safety, but
some medical experts are beginning to worry that the shiny little devices
that have taken the music world by storm could pose some risks for hearing
loss down the road, if they aren't used properly.
"People don't look into the sun to see if it damages their eyes," says
Dr.
Robert Sweetow, director of audiology at UCSF. "It continually amazes me
that people don't realize if you blast your ears, you're going to hurt
your ears."
Although there is no scientific data yet to support the contention,
audiologists like Sweetow are concerned that the portable music players
make it far too easy to listen to music for longer periods of time at an
excessive volume through the trademark "earbuds" manufactured by Apple and
other companies. With the earbuds -- earphones inserted into the ear that
come as standard equipment on portable music players -- the sound is
placed close to the eardrum, and the digital signal that delivers clean,
clear sound at virtually any volume without distortion, personal listening
devices can easily be played at unsafe levels.
The iPod manual contains a short warning about hearing loss ("If you
experience ringing in your ears, reduce the volume or discontinue use of
your iPod") and the company did remove the slogan "Play It Loud" recently
from the Apple Web site. Company spokespeople did not respond to repeated
requests for comment on this story. The issue, however, is less about the
devices themselves than about how they are used.
"There are three factors involved," says audiologist Douglas L. Beck,
director of professional relations for hearing aid manufacturers Oticon
Inc. "One is individual susceptibility and, two, how loud and, three, how
long. You can listen forever at reasonable loudness. If it's too loud, it
doesn't matter how long. It's a matter of loudness. If you can hear
headphones two or three feet away, it's probably too loud."
"Loudness is perceived," says Kathy Peck, co-founder of the Bay Area
organization HEAR (Hearing Education and Awareness for Rockers). "But
because it's digital and there's no distortion, it can be turned up really
loud."
"Any kind of personal listening device has that potential," says East Bay
audiologist Dr. Mont Stong. "They all have volume you can crank up until
it is detrimental. Car stereos can be played so loud you can hear them
across the street."
The difference between a car stereo, say, and an earbud is that the
latter
is placed in the ear and that much closer to the tympanic membrane. And
that's what worries some doctors.
"The closer you get to your eardrum, the less volume you need to hear
because the sound has less distance to travel," Stong says. "That's part
of the premise of a hearing aid, too, by the way. With headphones that go
over your ear -- instead of in -- the potential is less traumatic because
a lot of the volume is escaping out. With the earbuds, all the volume is
in your ear canal. People might get the perception that it's louder, but I
don't think they will."
When the Sony Walkman was introduced in the early '80s and launched the
personal listening device revolution, little attention was paid to hearing
safety. But the Walkman didn't really have the capacity for ear damage
that the digital MP3 players do, Sweetow says. The analog sound of the
little tape player would distort if turned up loud and the headphones were
funky little foam rubber pieces that leaked sound everywhere, as opposed
to the iPod's insert earphones. "The main difference between the Sony
Walkman and the iPod is the headphone," Sweetow says.
Even with the sound piped directly into the ear canal, noise from the
outside often competes with the music, and listeners turn it up louder.
People listening to music while riding BART trains, for example,
frequently increase the volume levels to drown out the sound of the
commute.
"Ear plugs they're not," says HEAR's Peck, who has firsthand knowledge of
how fragile a person's hearing can be: In 1988, she founded HEAR, an
advocate group aimed at musicians and music listeners, with Dr. Flash
Gordon of the Haight/Ashbury Free Medical Clinic after suffering hearing
damage in 1984 during a performance at the Oakland Coliseum. She was the
bass player in the San Francisco punk rock band the Contractions.
Another important factor is how long people are listening through their
earbuds. "Moms are coming in with their young sons because they're
listening to their iPods all the time," says Peck, whose organization
offers hearing testing. "They don't hear their mothers when they talk to
them. That could be just teenagers or it could be hearing damage from
overuse."
According to federal government safety standards, workers should not be
exposed to noise above 90 decibels for more than eight hours. For every
five-decibel increase, the permissible exposure time is cut in half.
Although the recommended safe duration for exposure to 120 decibels is
seven and a half minutes, many rock concerts lasting longer than an hour
reach and maintain that volume level. Some hearing care professionals feel
that these permissible levels are still too high.
Consulting rooms are not filling up with patients complaining of "iPod
ear" or anything like that. Any hearing damage from personal listening
devices will spend years in the pipeline. Stong, who also designs hearing
aids, says he is currently seeing middle-aged Baby Boomer patients with
hearing loss he believes was sustained by attending overly loud rock
concerts.
"Hearing loss is one of those things that is insidious," Sweetow says.
"It
comes on very slowly. If you're going to experience hearing loss from
music, it always starts in the high frequencies, which are above the pitch
of most conversations. Everybody knows when they've experienced a sudden
hearing loss. You may not notice a gradual loss until it is too late."
Doctors also are concerned that those in the main
personal-listening-device demographic are unlikely to take steps to
protect their hearing. "The primary group using iPods is younger people
and young people think they're invincible," Sweetow says. "With their
youthful optimism, they don't worry about damage."
Researchers at the National Acoustics Laboratories in Sydney recently
discovered some alarming information when surveying people listening to
music on the streets of Melbourne and Sydney. The study showed that 39
percent of 18- to 24-year-olds listened to personal units for at least an
hour every day and 42 per cent admitted that they thought they had the
volume too high.
A study published in December by Boston Children's Hospital found that
listening to a portable music player with headphones at 60 percent of its
potential volume for one hour a day is relatively safe. But personal
listening device users can easily spend many hours daily hooked up to
their earphones.
"The iPod is so convenient, so small, so inconspicuous and has such
high-quality sound, it encourages people to walk around with it all the
time," Sweetow says.
Sweetow, who once served as audiologist to the Grateful Dead, believes
that a five-minute rest period for every hour of listening is a good idea.
"Five minutes away an hour may not seem like a long time, but it has
tremendous recovery benefits for your ears," he said.
Ears adjust to loud volume. Audiologists call this a "temporary
threshold." According to Stong, anybody who has ever gotten back into
their car and turned on the radio, only to have to turn down the volume
from where they were listening previously has experienced a temporary
threshold shift.
"It's when the temporary shift becomes permanent that you have hearing
loss," Sweetow says.
"Hearing doesn't have any pain receptors," Stong says. "By the time you
reach the pain threshold, the damage has already been done."
"Loudness is psychological," Sweetow says. "Intensity is physical. People
are going to set the volume to the point where they have the loudness they
want. But what is going to cause damage to the ears is the physical
intensity. If you like the music, you will set it to a higher intensity
level because you want it to be louder."
"Apple's responsibility is to make a good, high-quality device," Beck
says. "People have to take responsibility for using it properly. It has to
be used responsibly, just like anything you have in your house."
E-mail Joel Selvin at jselvin@sfchronicle.com. Safe listening zone
Decibels Sounds
like... OSHA max.
exposure time
194 Loudest sound that can occur
150 Jet take-off
140 Jet engine at 100 feet
125 Pneumatic riveter, Pain begins
120 Car stereo, band practice 7.5 minutes
110 Dance clubs, headphones 30 minutes
107 Power mower 1 hour
100 Factory noise 2 hour
95* Subway train at 200 feet 4 hours
90 Train whistle at 500 feet
85 City traffic inside car
80 Dial tone of telephone
70 Normal conversation 3-5 feet
60 Normal conversation 3-5 feet
*Regular sustained exposure may cause permanent damage.
Source:
www.hearnet.com
John Blanchard / The Chronicle
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