decibel
Introduction:
1. First of all, we should understand a basic concept: decibel, which is the unit of sound pressure level (symbol: db). Every time the sound pressure doubles, the sound pressure level increases by 6 decibels. 1 dB is the sound that the human ear can just hear. Generally speaking, sounds below 20 decibels are considered quiet. Of course, generally speaking, sounds below 15 dB can be considered "dead".
2, 20-40 decibels is about the whispers of lovers' ears. 40-60 decibels belong to our normal conversation voice. Above 60 decibels, it belongs to the noisy range. When it reaches 70 decibels, we can think it is very noisy and begin to damage the auditory nerve. Above 90 decibels will damage hearing, and stay in the space of 100- 120 decibels. Unless there is an accident, people will be temporarily deaf for a minute.
3. The noise of cars varies from 80- 100 decibels. For example, if a car emits 90 decibels, 8 1 decibel can still be heard from 100 meters away (the above standards will vary according to environmental differences).