Doctors warn that a steady onslaught of loud noise, particularly through ear buds, is damaging the hearing of a generation wired for sound, although they may not realize it for years. More than 1 billion young people are at risk of hearing loss because of personal audio devices, such as smartphones, and damaging levels of sound at entertainment venues like electronic dance music festivals, where noise levels can top 120 decibels for hours, according to the World Health Organization.

"Probably the largest cause [of hearing damage] is millennials using iPods and [smartphones]," says Dr. Sreekant Cherukuri, an ear, nose, and throat specialist. Hearing loss among today's teens is about 30 percent higher than in the 1980s and 1990s, Cherukuri estimates.

"You (once) had a Walkman with two AA batteries and headphones that went over your ears," he told NBC News. "At high volume, the sound was so distorted and the battery life was poor. Nowadays, we have smart phones that are extremely complex computers with high-level fidelity."

The damage happens when sound travels from the earbud deep inside your ear to the cochlea, where some 20,000 hair cells transmit the sound to the brain. But if the sound is too loud, and listened to for too long, it can damage those hair cells, or worse, cause them to die off. Permanent damage can happen in minutes, experts say.

Possible Preaching Angles: Physical hearing loss is a serious situation, but spiritual hearing loss is devastating. Will anyone in the wired generation be able to hear the voice of God amidst the constant barrage of noise?