How Loud is Too Loud for your iPod? - Video

(Original Link (with VIDEO)- http://www.sciencedaily.com/videos/2007/0610-mp3_players_how_loud_is_too_loud.htm)

Loud, sustained sound can damage tiny hairs in the cochlea, and yet 80 percent of people listen to personal music devices at dangerous levels above background noise, a study by acousticians shows. Certain models of earphones are safer for the ear, the study also concluded.

Can you hear me now? Not if you've pumped up the volume on your MP3 player. In noisy places, everyone is turning up the tunes, and they could be drowning out their own hearing. A new study tells how loud is too loud.

Audiologists Brian Fligor, Sc.D., and Terri Ives have identified safe volume levels for you to use in noisy places. Dr. Fligor, an audiologist and Director of Diagnostic Audiology at Children's Hospital Boston says, "Your typical listener is not at risk if they are listening in a quiet situation, but if they are in a noisier situation, such as commuting, they very easily are going to be at risk." Their study concludes that 80 percent of people listen at dangerous levels when background noise comes into play.
As sound travels through the ear canal, it ends up in the inner ear, or cochlea. When it's too loud, tiny hair cells, which send sound information to the brain, are damaged or destroyed. "They're not meant to be hit with noise for long periods of time," Dr. Fligor says. Over time, this can lead to permanent damage of the hair cells and your hearing.

The study concludes the average person listens to music at the same noise level as we hear a gas lawnmower. So what can you do? Dr. Fligor says, "Something that people can do is set their music to a comfortable level when they are in a quiet situation." Dr. Fligor recommends leaving it at that safe level, 75 decibels or below, and investing in earphones that block out background noise.

During the study, only twenty percent of patients who used "in-the-ear" earphones, designed to block out background noise, exceeded sound levels considered to be risky, compared to 80 percent who listen dangerously with other types of earphones. Proof that your choice of earphone combined with smart volume control settings can help save your hearing. Turning down the music will ensure you will be able to hear music in the future.

BACKGROUND: As portable digital music players -- iPods and other MP3 players -- become more and more popular, people are becoming concerned about whether they are dangerous to our hearing. Now hearing researchers have measured specific sound levels in a variety of players using several different types of earphones. They used this information to develop the first detailed guidelines with safe volume levels for listening to the iPod with earphones. They also evaluated the output levels of several other popular players to determine any risks to hearing from using these devices.

ABOUT HEARING LOSS: Loud sounds stress and could damage the delicate hair cells in the inner ear that convert mechanical vibrations in the air (sound) into the electrical signals that the brain interprets as sound. If exposed to loud noises for a long time, the hair cells can become permanently damaged and no longer work, producing hearing loss. Noise-induced hearing loss can be caused by two types of noise: sudden bursts, such as firearms or fireworks; or continuous exposure to loud noise, such as motorized recreational vehicles, loud sporting events, power tools, farming equipment, or amplified music. For a person to lose their hearing because of continuous exposure, it would depend on how loud the sound was and how often and for how long they heard it. It takes repeated exposures over many years to cause a noise-induced hearing loss in both children and adults.

WHAT THEY FOUND: The researchers conducted a study observing the listening habits of 100 graduate students listening to iPods through earphones. They found that all the players had very similar sound output levels. Also, in-ear earphones, which broadcast sound directly into the ears, are no more dangerous than headphones placed over the ears. However, if the user listens to music in noisy surroundings, they are much more likely to raise the volume to risky levels, suggesting that people should seek quieter listening areas when possible, and use earphones that block out background noise.

RECOMMENDED LEVELS: The more often and the louder you player your player, the more likely you'll experience some hearing loss. To come up with recommended listening times and sound levels, the researchers compared the players' volume levels to the minimum sound level for the risk of hearing damage: 85 dBA. Typically, a person can tolerate about two hours of 91 dBA per day before risking hearing loss. The researchers recommend listening to iPods for -- hours a day with earphones if the volume is at 80% of maximum levels. Listening at full volume is not recommended for more than 5 minutes per day using the earphones that come with the player.

Hooked on Headphones? Personal Listening Devices Can Harm Hearing, Study Finds

(Original Link - http://www.sciencedaily.com/releases/2010/08/100831221525.htm)

ScienceDaily (Sep. 1, 2010) — Personal listening devices like iPods have become increasingly popular among young -- and not-so-young -- people in recent years. But music played through headphones too loud or too long might pose a significant risk to hearing, according to a 24-year study of adolescent girls.

The study, which appears online in the Journal of Adolescent Health, involved 8,710 girls of lower socioeconomic status, whose average age was about 16. Their hearing was tested when they entered a residential facility in the U.S Northeast.

"I had the rare opportunity, as an audiologist, to see how this population changed over the years," said Abbey Berg, Ph.D., lead study author and a professor in the Department of Biology & Health Sciences at Pace University in New York.

In this period, high-frequency hearing loss -- a common casualty of excessive noise exposure -- nearly doubled, from 10.1 percent in 1985 to 19.2 percent, she found.

Between 2001, when testers first asked about it, and 2008, personal music player use rose fourfold, from 18.3 percent to 76.4 percent. High-frequency hearing loss increased from 12.4 percent to 19.2 percent during these years, while the proportion of girls reporting tinnitus -- ringing, buzzing or hissing in the ears -- nearly tripled, from 4.6 percent to 12.5 percent.

Overall, girls using the devices were 80 percent more likely to have impaired hearing than those who did not; of the teens reporting tinnitus, all but one (99.7 percent) were users.

However, "just because there's an association, it doesn't mean cause and effect," Berg said. For the girls who took part in the study, other aspects of their lives -- poverty, poor air quality, substance abuse, risk-taking behavior -- might Sadd to the effects of noise exposure.

"This paper offers compelling evidence that the inappropriate use of headphones is indeed affecting some people's hearing, and the number of 'some people' is not small," said Brian Fligor, director of diagnostic audiology at Children's Hospital Boston.

The level of impairment detected in this study might have been relatively subtle "but the point is that it is completely avoidable," said Fligor, who has no affiliation with the study.

"The ear is going to be damaged throughout your lifetime; what we're seeing here resembles early onset age-related hearing loss -- you might think of it as prematurely aging the ear," he said.
"I don't demonize headphones," said Fligor, who encourages moderation, not prohibition. At a reasonable volume -- conversational or slightly louder -- there's little risk, he said: "It's when you start overworking the ear that you get problems."

Berg said her findings suggest the need for more effective educational efforts to reduce unsafe listening behavior, particularly among disadvantaged youth. "You have to target them at a much younger age, when they are liable be more receptive," she said.

New Norwegian Earplug Solution to a Deafening Problem

(Original Link - http://www.sciencedaily.com/releases/2010/08/100820072151.htm)

ScienceDaily  — Some 600 cases of noise-induced hearing impairment are reported by the Norwegian petroleum industry every year. A new, intelligent earplug is now set to alleviate the problem.

Norway's largest company, Statoil ASA, is taking the problems associated with noise exposure seriously. Over the course of four years the international energy company has led efforts to further develop an existing combined hearing protection and communication product for use on offshore platforms.

World's most advanced hearing protection device

A microphone on the outside of the new "offshore" version of the QUIETPRO earplug picks up ambient sounds. The sound is digitally processed, and unwanted loud noises are filtered out before the sound is sent to a speaker inside the earplug. Users can adjust the level of ambient sound, as desired.
A microphone on the inside of the earplug picks up speech signals through the skull. This means that users do not have to have a microphone in front of their mouth, as is the case with the ear protection devices currently used on most offshore platforms. Another advantage is that the microphone inside the ear does not pick up background noise in the way that a microphone in front of the mouth does.
The QUIETPRO hearing protection and communication device was originally developed for military use by the Trondheim-based company Nacre AS, which has its origins in Scandinavia's largest independent research organisation, SINTEF. The company's customers include the United States Army, which uses QUIETPRO devices in armoured vehicles, among other applications.

More energy and increased safety

"The new hearing protection device enables employees to preserve a lot of energy," explains Asle Melvær, noise specialist at Statoil, who initiated and is responsible for the R&D project Offshore Safety for Hearing and Verbal Communication (SoHot). The project receives funding under the Research Council of Norway's Large-scale Programme for Optimal Management of Petroleum Resources (PETROMAKS).

"Users of the new device do not have to strain to hear what is being said over the radio, and the noise reduction system in the earplug means that the level of sound is adapted to the surrounding environment. On board an oil platform understanding messages transmitted by radio can be a matter of life and death," states Mr Melvær.
The earplug also alerts the user if it is not inserted into the ear correctly, providing additional safety.

New generation soon to be tested

The hearing protection device was tested in 2009 on the helicopter landing pad at the Oseberg Field Centre outside Bergen. Starting in December 2010 the next generation of devices will be tested both there and at the Snorre oilfield a little further north.

"One important feature of the new version is a built-in noise dose meter that emits a warning signal before any damage to hearing has occurred -- which is quite unique," explains an enthusiastic Asle Melvær. "This function will make it possible for us to withdraw personnel from hazardous noise areas before they have been exposed to noise levels that can damage their hearing."
The new earplug is explosion-proof and can be used anywhere on the platform.

Important initiative

"It is wonderful to be able to play a role in the development of new technology that will undoubtedly reduce the number of cases of hearing damage among employees in the petroleum industry," says Mr Melvær. "Nevertheless, it is important to emphasise that the development of better hearing protection must not become an excuse for failing to implement measures to reduce noise levels. This should still be given first priority," he states.

Research Council supports HSE projects

The PETROMAKS programme is responsible for the Research Council's health, safety and environment-related (HSE) activities within the petroleum sector. "Efforts to develop a new version of the QUIETPRO earplug provide a good example of the type of creative projects that exist in this field that make use of technology and system solutions across sectors," explains Tor-Petter Johnsen, Adviser for the PETROMAKS programme.

"Close cooperation between advanced Norwegian technology groups and highly skilled customers in the petroleum industry has not only led to the development of a new product but has also provided better insight into the serious health risks to which employees in the industry are exposed," Mr Johnsen concludes.