>The idea is to minimize unsafe listening practices, which depend on two factors: how long you listen and how loud the sound is. The sound of a typical conversation is 60 decibels, which won’t cause any hearing problems. But an idling bulldozer is about 85 decibels, which can cause permanent damage after eight hours. Sounds like a clap of thunder or even a close vuvuzela clock in at 120 decibels, damaging hearing after just nine seconds.
I phrased my first comment a bit poorly. There is a lower limit to what is damaging, but my point is like the quote says, even volumes which aren't extreme can damage your ear if you expose your ear to that level of sound for an extended period of time.
Here is an article by Popular Science that talks about relationship between volume and period of time: http://www.popsci.com/limit-headphone-time-hour-day-says-who
FTA:
>The idea is to minimize unsafe listening practices, which depend on two factors: how long you listen and how loud the sound is. The sound of a typical conversation is 60 decibels, which won’t cause any hearing problems. But an idling bulldozer is about 85 decibels, which can cause permanent damage after eight hours. Sounds like a clap of thunder or even a close vuvuzela clock in at 120 decibels, damaging hearing after just nine seconds.
I phrased my first comment a bit poorly. There is a lower limit to what is damaging, but my point is like the quote says, even volumes which aren't extreme can damage your ear if you expose your ear to that level of sound for an extended period of time.