Loud music and noise causes hearing loss by damaging the delicate hair nerve cells in the cochlea, a part of the inner ear that helps transmit sound impulses to the brain. These hair cells often recover from temporary damage. However, permanent damage can occur with prolonged exposure to extremely loud or moderately loud noise. When these nerve hair cells are destroyed, irreversible hearing loss results.
Many people who listen to iPods in noisy environments pump up the volume to dangerous levels to drown out background noise. Busy city hubs and subway noise (around 90 decibels) are already sufficiently loud to cause permanent damage with considerable exposure. Although the damage from chronic exposure to these sound levels is generally slow, it is cumulative. Music lovers who tolerate noise levels above 85 decibels for long periods will end up with irreversible hearing loss.