Back in the early days of portable audio players, headphones were quite commonly used for private listening, however as time went on, ear-buds gradually replaced the bulkier headphones due to their very small compact size and how cheap they have become. As these ear-buds can easily output in excess of 110 decibels with some MP3 players, there have been a lot of warnings about prolonged listening causing permanent hearing-loss with listeners as young as children.
Recently, a North-western University audiologist has issued a warning about using iPods with their included ear-buds, since a study has found that due to how close the ear-buds are present to the eardrum, they effectively magnify the sound by between 6 and 9 decibels compared with traditional over-ear headphones. Also, as these players have the ability to play up to 20 hours of continuous music depending on the player, users also tend to listen to a lot more music than with cassette tapes and CDs.
One friend of an audiologist at the university has carried out random tests on students he encounters listening to music and found some listening to music as loud as 120 dB; loud enough to potentially cause hearing loss in just 1 hour 15 minutes of continuous exposure. While over-ear headphones are less likely to cause harm due to their lower intensity, he recommends choosing noise-cancelling headphones, since these also block out most external noise, thus making the user much less likely to turn up the volume as loud. Alternatively, as consumers prefer ear-buds, he recommends adopting a 60% : 60min rule, where the listener should keep the volume below 60% maximum volume and only listen up to an hour’s worth per day.
I can't say I'm surprised by this one. How can Apple make a device that's so loud? No common sense there. If I were a headphone maker, I would put this on each package!
From CD Freaks.
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