There is considerable interest in the amount of damage to one’s hearing that listening to an iPod (or similar portable audio player) can cause. I’ve posted before on Apple’s attempt to prevent harm to hearing from iPods and discussed possible improvements. In the absence of such a solution, it’s important that people understand safe listening levels for iPods and similar devices.
At the recent annual conference of the American Auditory Society, researchers from the University of Colorado and the Children’s Hospital Boston presented the latest data on how long one can safely listen to digital portable music players (Portnuff and Fligor, Output Levels of Portable Music Players).
Firstly, they showed that the danger among all of the players tested (iPod, iPod Mini, iPod Nano, Creative Zen Micro, Sandisk Sansa) are approximately the same. In other words, iPods are no worse for your hearing than any of their competitors.
Secondly, there was no difference in danger to your hearing between different music genres. Believe it or not, R&B music is as potentially damaging as Rock music or Country music. No word on the danger from Opera (although some might suggest that the true danger lies in falling asleep and being exposed to hours of Wagner—or perhaps the danger is in staying awake).
Thirdly, how long you can safely listen to your music player depends on what you are listening with. People choose different earphones to listen to their player: some use the buds provided with the player, some upgrade to expensive insert earphones such as the Etymotic ER6s or Shure E4cs. Some choose to use large headphones that sit over the ears. Depending on which you use, your safe duration of listening is different.
The table below shows the levels calculated by the Boston University researchers that reach the 50% noise dose per day according to NIOSH standards. Exceeding these levels is not a good idea.
For example, if you use Etymotic ER6s (categorized as “Isolators” in the table below) and you are listening with the music player’s volume control at 80%, then you should not listen for more than 50 minutes a day. The authors of this research report even suggest that “more conservative recommendations may be warranted.” Listener beware.