With so many portable audio devices available these days, an increasing number of us have begun using earphones on a daily basis. Earphones, or earbuds, offer many desirable benefits ranging from convenient portability, to greater external noise isolation. Everywhere, people can be seen walking around with those tell-tale cords dangling from their ears; this is a true testament to our love of music and audio.
However, an indirect effect of this habit is the possibility of damaging your ears, lessening your ability to hear. Damaging your hearing in this way is referred to as Noise-Induced Hearing Loss (NIHL). Since we need our ears to continue enjoying audio, it is crucial to follow safety precautions when using earphones.
Two of the main factors which contribute to hearing damage/loss are sound levels and duration.
Loud sounds can damage your ears! Typically, any sound louder than 85 decibels (dB) is considered dangerous to your hearing. Sounds levels above 120dB may cause pain. When using earbuds, the audio is transmitted directly to your ear canal. This close proximity reduces the amount of sound that escapes, thus increasing the loudness. Unfortunately, many people make the common mistake of increasing their earphone volume in an attempt to get better sound, or to block out external noise. If your ears are routinely subjected to loud noise for extended periods of time, they begin to adapt. This adaptation may lead people to further increase the audio of what they are listening to and risk damage to their hearing.
The amount of time spent listening with earbuds or earphones also increases the risk of hearing damage and/or loss. Brief exposure to a 90dB sound may not damage your hearing, but if your ears are exposed for extended durations, there is a definite risk. In fact, if you were to listen to the 90dB sound for three hours, you could cause the same damage as a 150dB, 30 second sound blast. 150dB is the average sound level of a shotgun! So if a person is already using their earbuds at a level greater than 85dB and they are doing so for extended periods of time, there is a very high risk of permanent noise-induced hearing loss. Remember, the louder the sound, the shorter the duration of safe listening.
To understand how loud sounds damage your ability to hear, we must first understand how our ears function. Please see the diagram below.
Sound reaching the outer ear is funneled through the canal to ear drum. The sound causes the eardrum to vibrate, which in turn causes the malleus (mallet), incus (anvil), and stapes (stirrup) to also vibrate. The vibration of these three bones has an amplifying effect on the sound. The amplified sound is then transmitted to the fluid-filled cochlea. As the fluid in the cochlea vibrates, traveling waves are formed. Small sensory “hair” cells located on a membrane of the cochlea move with the motion of the traveling waves. This causes them to be pushed against an adjacent membrane. When these sensory “hairs” are agitated in this way, they are able to accept an inrush of chemicals which cause an electric signal to be generated. The auditory nerve transmits the electric signal to the brain.
Noise-Induced Hearing Loss occurs when loud sounds cause molecules to form in the ear which damage the small sensory cells. When the destruction of the sensory cells reaches a certain point, the damage can be irreversible, and the hearing loss may be permanent! Loud sounds can also damage the auditory nerve. Young, developing children are at especially high risk, so special attention should be given to developing and encouraging precautionary behavior in kids.
How to Prevent Damage to your Ears
The best way to avoid Noise-Induced Hearing Loss is to keep your audio below 85dB and avoid prolonged use. Many people don’t exactly know how loud 85dB is. Vacuum cleaners, noisy restaurants, and New York City traffic have all been rated right around 85dB and are great examples. Your listening habits are yours to determine. Some people use the 60/60 rule: 60% volume for no more than 60 minutes per day. However, that may be a bit loud depending on the volume settings of your audio player. It is good to arrange safe habits around your listening schedule. For example, if you listen to audio while running for hours, keep your volume down around 30%. If you want to rock out to that really heavy song, feel free to turn it up to 50% volume, just make sure you’re not listening to the super-long, extended version! A good rule of thumb is, if you think your volume is perfect; turn it down just a bit.
A good set of high quality, well designed earphones can have a great impact on minimizing the risk of NIHL. Better quality drivers offering high-fidelity sound provide better audio, which requires less volume to get an improved listening experience. Some really nice earbuds are designed to fit into your ear instead of simply hanging on the outer ear. This puts the audio closer to your eardrum, decreasing the amount of necessary volume. Sound-isolation features are another component to look for in a good set of earphones. Poor quality earbuds often offer little or no sound isolation. This allows more external noise to interfere with the audio you’re trying to listen to, which causes many people to increase the volume beyond safe levels. There are also some really innovative people out there currently creating some incredible technology aimed at reducing and/or eliminating the harmful effects of earbud listening.
Earbuds are great options for portable audio enjoyment. By following a few precautionary guidelines, and using a high quality set of earbuds, you’ll be able to enjoy your favorite audio for years to come.