Noise is carried by waves that spread out in all directions. Everyone is affected, although to different degrees. However, there are a certain number of constants.

For example, the threshold of auditory pain is 130 decibels, but a number of intermediary levels and their effects are also well known. The rustling of leaves is equivalent to 20 decibels, a normal conversation is 60 decibels. But a horn at five meters or a rock concert can reach – or even exceed – 100 decibels.