What is the difference between a deafening sound and a loud sound?
A deafening sound is a noise which is so high in amplitude and frequency which can make you deaf, whereas a loud sound can seem unpleasant but it does not usually cause long time effects.
Sound up to 80 decibels can be very loud.
#91#decibels, your ears can tolerate up to two hours of exposure.
#100#decibels, damage can occur with #15#minutes of exposure.
#112#decibels, damage can occur with only one minute of exposure.
#140#decibels, immediate nerve damage can occur.
The above was taken from here.
So these are the levels of a deafening sound.