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.
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.
The Acoustical Society of America contributed to the information contained in the TV portion of this report.