MP3 Players, Earbuds, and Protecting Your Hearing

One of the important elements of the inner ear is the cochlea. This structure is composed of many parts and includes thousands of tiny hairs that vibrate at different frequencies. Those vibrations are interpreted by nerve cells and unfortunately the cells can be destroyed by loud sounds. Listen to enough loud sounds for long enough, you will kill enough of those nerve cells and begin to experience hearing loss.

Audiologist Scott Bradley makes this great analogy about sounds and hearing loss. He says we can think of the hair cells as grass and loud sounds as people. One person walking on the grass is unlikely to hurt anything but if a lot of people walk over the grass, and keep doing this, it can cause permanent damage.

Loud sounds come in many forms but first let's try and get an idea of what loud really is. Sound meters use a scale that is labeled in decibels and we can use some simple sounds to give us an idea of the relatively "loudness" of different noises. Normal talking is around 60 decibels. A gas powered lawn mower that you are standing next to is 90 decibels. A chain saw is over 100 decibels and can begin to damage your ears after a half hour of exposure.

Most people do not experience problems with potentially loud noises because they are either far enough away from a noise or are not exposed the sound for a long enough period of time. A jet can be loud if it flies a ½ mile overhead but it is relatively far and it will pass over us fairly quickly. A loud concert in a music hall or closed arena is a problem because the sound is all around us, is not far away, and goes on for an extended period. A problem with MP3 players and earbuds is that we put the source of the sound right next to our eardrums, and the inner ear that lies just beyond that thin membrane. Many people also listen to music for hours at a time.

Scientists have become concerned, and more and more alarmed, that young people are listening to music too loud and long, and damaging their hearing. A famous 2001 study in the journal Pediatrics is one of the most cited sources of hearing loss evidence. Not everyone agrees with the study's findings but they are interesting. Researcher Amanda Sue Niskar and others at the Centers for Disease Control and Prevention studied over 5,000 6 to 19 year olds. They found that 12 % showed some signs of noise related hearing loss. If true, this would mean that 5 million young people have damaged hearing.

This same problem is also faced by adults too of course. Yet unlike children that may not be so easy to convince to lower the volume, most adults are perhaps a little less inclined to listen to music at high volumes. One way that adults potentially get into trouble unwittingly is when they are wearing earbuds and listening to music in an effort to eliminate outside sounds. There are plenty of folks that regularly commute on buses, trains or are frequent fliers that use an MP3 player to make their trip a little nicer. Some earbuds are good at blocking outside sounds or there are even noise canceling earbuds that can help with the problem of commuting noise. If you do not have such special earbuds a common reaction is to simply turn the music higher in order to drown out the outside sounds. As a regular bus commuter, I know there are many people that get on the bus I take and have the music so loud on their MP3 player that you can hear it from 5 rows away.

An audiologist at Wichita State University who regularly pulls out student's earbuds and asks if he can measure the sound decibels regularly finds turned up loud volume that registers at 110 and even 120 decibels. This is probably what some of my fellow bus riders are experiencing and this is the equivalent of being at a loud rock concert. Returning to Scott Bradley's people walking on the grass analogy, he says 120 decibels is like driving a tank on the grass. It is not hard to damage your nerve cells at this level.

It is important to not set the volume very high when listening to earbuds and, especially if you listen to things on the loud side, to not listen for many hours at a time. One sound researcher suggests a 60/60 rule for earbud users: only listen to your music at 60% volume and only listen for an hour a day maximum. If you are commuting and trying to block out sounds, do realize too that while it is tempting to turn your music louder when the background noise gets loud - you may not be doing yourself any favors!

If you have children that like to listen to music and may listen to it to loud, you might want to consider a set of volume limiting earbuds. These are made by Ultimate Ears and are pretty effective on cutting down the decibles. According to their sales copy "Loud Enough earphones are designed specifically for children featuring a built-in volume reducer and a small form factor that's comfortable for smaller ears. Relative to other noise-isolating earphones, these innovative ear buds reduce sound pressure levels by up to 20dB."